All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
Radiodoc
**********
:I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
:
:Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
:
:Radiodoc
:**********
:
Job,
And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
Radiodoc
***********
:
::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
I will wait for further instructions to determine what is wrong with this radio.
Thanks
::Job,
::
::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
::
::Radiodoc
::**********
::
:Job,
:
:And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
:
:Radiodoc
:***********
:
::
:::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
Radiodoc
************
:Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
:I will wait for further instructions to determine what is wrong with this radio.
:Thanks
:
:::Job,
:::
:::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
:::
:::Radiodoc
:::**********
:::
::Job,
::
::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
::
::Radiodoc
::***********
::
:::
::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
Regards
:
:Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
:
:Radiodoc
:************
:
:
::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
::I will wait for further instructions to determine what is wrong with this radio.
::Thanks
::
::::Job,
::::
::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
::::
::::Radiodoc
::::**********
::::
:::Job,
:::
:::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
:::
:::Radiodoc
:::***********
:::
::::
:::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
Radiodoc
***********
::Job,
:
:Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
:Regards
:
:
::
::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
::
::Radiodoc
::************
::
::
:::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
:::I will wait for further instructions to determine what is wrong with this radio.
:::Thanks
:::
:::::Job,
:::::
:::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
:::::
:::::Radiodoc
:::::**********
:::::
::::Job,
::::
::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
::::
::::Radiodoc
::::***********
::::
:::::
::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
Thanks
:Job,
:
:Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
:
:Radiodoc
:***********
:
:
:::Job,
::
::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
::Regards
::
::
:::
:::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
:::
:::Radiodoc
:::************
:::
:::
::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
::::I will wait for further instructions to determine what is wrong with this radio.
::::Thanks
::::
::::::Job,
::::::
::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
::::::
::::::Radiodoc
::::::**********
::::::
:::::Job,
:::::
:::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
:::::
:::::Radiodoc
:::::***********
:::::
::::::
:::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
Radiodoc
************
:
:Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
:Thanks
:
:
:
::Job,
::
::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
::
::Radiodoc
::***********
::
::
::::Job,
:::
:::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
:::Regards
:::
:::
::::
::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
::::
::::Radiodoc
::::************
::::
::::
:::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
:::::I will wait for further instructions to determine what is wrong with this radio.
:::::Thanks
:::::
:::::::Job,
:::::::
:::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
:::::::
:::::::Radiodoc
:::::::**********
:::::::
::::::Job,
::::::
::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
::::::
::::::Radiodoc
::::::***********
::::::
:::::::
::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
Regards
:Job,
:
:With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
:
:Radiodoc
:************
:
:
::
::Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
::Thanks
::
::
::
:::Job,
:::
:::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
:::
:::Radiodoc
:::***********
:::
:::
:::::Job,
::::
::::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
::::Regards
::::
::::
:::::
:::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
:::::
:::::Radiodoc
:::::************
:::::
:::::
::::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
::::::I will wait for further instructions to determine what is wrong with this radio.
::::::Thanks
::::::
::::::::Job,
::::::::
::::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
::::::::
::::::::Radiodoc
::::::::**********
::::::::
:::::::Job,
:::::::
:::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
:::::::
:::::::Radiodoc
:::::::***********
:::::::
::::::::
:::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
If jumpering across the choke killed the voltage coming into the choke (killed anode voltage on the 6F6 & 6AD7) then there has to be a short on the out side of the choke. A suspect is the 30mfd cap between the choke out lead and chassis. If you replaced the power supply caps with individual caps, did you completely isolate the original cap from the circuit and observe polarity of the replacements? Generally the metal shell of a cap is the negative lead, the other lead positive. May try disconnecting the 30 mfd cap from the circuit leaving all other wires connected to each other and try powering up again. Check your wiring also with the schematic.
Radiodoc
************
:Doc-----I followed your instructions and measured voltage going into choke...270v.....no voltage measured coming out of choke. Connected jumper leads across choke but did not receive any voltage on pin 4 of 6F6 tube. Actually I lost voltage on the anodes of 6F6 and 6SK7 while being connected across the choke.....don’t know what this all means. Will wait for further instructions.
:Regards
:
:
::Job,
::
::With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
::
::Radiodoc
::************
::
::
:::
:::Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
:::Thanks
:::
:::
:::
::::Job,
::::
::::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
::::
::::Radiodoc
::::***********
::::
::::
::::::Job,
:::::
:::::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
:::::Regards
:::::
:::::
::::::
::::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
::::::
::::::Radiodoc
::::::************
::::::
::::::
:::::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
:::::::I will wait for further instructions to determine what is wrong with this radio.
:::::::Thanks
:::::::
:::::::::Job,
:::::::::
:::::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
:::::::::
:::::::::Radiodoc
:::::::::**********
:::::::::
::::::::Job,
::::::::
::::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
::::::::
::::::::Radiodoc
::::::::***********
::::::::
:::::::::
::::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
I disconnected the 30 mfd capacitor but again did not have any voltage on the screen grids, and lost all voltage when I connected a jumper across the speaker choke. I should make note that although I wasn’t receiving any voltage there was a hum coming through the speaker, both before and after disconnecting the 30 mfd cap....i.e. when jumper is across choke.
I am going to give you a run down of the electrolytic cap connections just in case I do have connections wrong.
Negatives of 30 mfd, 20 mfd, and 5 mfd joined together.....lead from them going to pin1(sh), to pin 3(g3), to pin 5(k) of 6SK7. Then through a .06uf capacitor to a connection located on bottom right corner of the third I.F Transformer which goes to ground through a series of resistors.
Positive of 30 mfd elec. Cap connected to pin 4(g2) of 6F6 to pin 4(g2) of 6AD7.....plus others.
Positive of 20 mfd elect cap going to a connector on the splitter resistor plus pin 6(g2) 6SK7 and pin 4(g2) 6SA7...plus others.
Positive of 5 mfd elect. Cap to anodes of 6AD7 and 6R7, etc.
Negative of 100 mfd and 40 mfd joined......connected to end of splitter resistor and then to power transformer....also connected to pin 5(g) 6F6...plus others.
Positive of 100 mfd connected to end of tone control and I’m assuming it’s the negative end....also connected to pin 3(g3) 6SK7... and others.
Positive of 40 mfd connected to end of splitter choke.....from splitter choke to pin 2(f+) 5U4.
If you’re not discouraged Doc, I’m won’t be either.
Regards
:Job,
:
:If jumpering across the choke killed the voltage coming into the choke (killed anode voltage on the 6F6 & 6AD7) then there has to be a short on the out side of the choke. A suspect is the 30mfd cap between the choke out lead and chassis. If you replaced the power supply caps with individual caps, did you completely isolate the original cap from the circuit and observe polarity of the replacements? Generally the metal shell of a cap is the negative lead, the other lead positive. May try disconnecting the 30 mfd cap from the circuit leaving all other wires connected to each other and try powering up again. Check your wiring also with the schematic.
:
:Radiodoc
:************
:
:
::Doc-----I followed your instructions and measured voltage going into choke...270v.....no voltage measured coming out of choke. Connected jumper leads across choke but did not receive any voltage on pin 4 of 6F6 tube. Actually I lost voltage on the anodes of 6F6 and 6SK7 while being connected across the choke.....don’t know what this all means. Will wait for further instructions.
::Regards
::
::
:::Job,
:::
:::With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
:::
:::Radiodoc
:::************
:::
:::
::::
::::Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
::::Thanks
::::
::::
::::
:::::Job,
:::::
:::::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
:::::
:::::Radiodoc
:::::***********
:::::
:::::
:::::::Job,
::::::
::::::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
::::::Regards
::::::
::::::
:::::::
:::::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
:::::::
:::::::Radiodoc
:::::::************
:::::::
:::::::
::::::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
::::::::I will wait for further instructions to determine what is wrong with this radio.
::::::::Thanks
::::::::
::::::::::Job,
::::::::::
::::::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
::::::::::
::::::::::Radiodoc
::::::::::**********
::::::::::
:::::::::Job,
:::::::::
:::::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
:::::::::
:::::::::Radiodoc
:::::::::***********
:::::::::
::::::::::
:::::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:::::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
Lift (unsolder) the out lead of the speaker choke. Try measuring for voltage then. If still no voltage then the problem may be the choke is shorted to the speaker frame and chassis/ground somehow.
Radiodoc
************
:Hi Doc-----First, the old electrolytic cap containers are isolated from the circuit. All new caps were installed and to the best of my knowledge polarity have been followed and I have checked all connections once more.
:I disconnected the 30 mfd capacitor but again did not have any voltage on the screen grids, and lost all voltage when I connected a jumper across the speaker choke. I should make note that although I wasn’t receiving any voltage there was a hum coming through the speaker, both before and after disconnecting the 30 mfd cap....i.e. when jumper is across choke.
:I am going to give you a run down of the electrolytic cap connections just in case I do have connections wrong.
:
:Negatives of 30 mfd, 20 mfd, and 5 mfd joined together.....lead from them going to pin1(sh), to pin 3(g3), to pin 5(k) of 6SK7. Then through a .06uf capacitor to a connection located on bottom right corner of the third I.F Transformer which goes to ground through a series of resistors.
:
:Positive of 30 mfd elec. Cap connected to pin 4(g2) of 6F6 to pin 4(g2) of 6AD7.....plus others.
:
:Positive of 20 mfd elect cap going to a connector on the splitter resistor plus pin 6(g2) 6SK7 and pin 4(g2) 6SA7...plus others.
:
:Positive of 5 mfd elect. Cap to anodes of 6AD7 and 6R7, etc.
:
:Negative of 100 mfd and 40 mfd joined......connected to end of splitter resistor and then to power transformer....also connected to pin 5(g) 6F6...plus others.
:
:Positive of 100 mfd connected to end of tone control and I’m assuming it’s the negative end....also connected to pin 3(g3) 6SK7... and others.
:
:Positive of 40 mfd connected to end of splitter choke.....from splitter choke to pin 2(f+) 5U4.
:
:If you’re not discouraged Doc, I’m won’t be either.
:
:Regards
:
:
::Job,
::
::If jumpering across the choke killed the voltage coming into the choke (killed anode voltage on the 6F6 & 6AD7) then there has to be a short on the out side of the choke. A suspect is the 30mfd cap between the choke out lead and chassis. If you replaced the power supply caps with individual caps, did you completely isolate the original cap from the circuit and observe polarity of the replacements? Generally the metal shell of a cap is the negative lead, the other lead positive. May try disconnecting the 30 mfd cap from the circuit leaving all other wires connected to each other and try powering up again. Check your wiring also with the schematic.
::
::Radiodoc
::************
::
::
:::Doc-----I followed your instructions and measured voltage going into choke...270v.....no voltage measured coming out of choke. Connected jumper leads across choke but did not receive any voltage on pin 4 of 6F6 tube. Actually I lost voltage on the anodes of 6F6 and 6SK7 while being connected across the choke.....don’t know what this all means. Will wait for further instructions.
:::Regards
:::
:::
::::Job,
::::
::::With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
::::
::::Radiodoc
::::************
::::
::::
:::::
:::::Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
:::::Thanks
:::::
:::::
:::::
::::::Job,
::::::
::::::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
::::::
::::::Radiodoc
::::::***********
::::::
::::::
::::::::Job,
:::::::
:::::::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
:::::::Regards
:::::::
:::::::
::::::::
::::::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
::::::::
::::::::Radiodoc
::::::::************
::::::::
::::::::
:::::::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
:::::::::I will wait for further instructions to determine what is wrong with this radio.
:::::::::Thanks
:::::::::
:::::::::::Job,
:::::::::::
:::::::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
:::::::::::
:::::::::::Radiodoc
:::::::::::**********
:::::::::::
::::::::::Job,
::::::::::
::::::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
::::::::::
::::::::::Radiodoc
::::::::::***********
::::::::::
:::::::::::
::::::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::::::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
:
:Lift (unsolder) the out lead of the speaker choke. Try measuring for voltage then. If still no voltage then the problem may be the choke is shorted to the speaker frame and chassis/ground somehow.
:
:Radiodoc
:************
Job,
I should have said measure for voltage from the choke out lead.
Radiodoc
*************
:
:
::Hi Doc-----First, the old electrolytic cap containers are isolated from the circuit. All new caps were installed and to the best of my knowledge polarity have been followed and I have checked all connections once more.
::I disconnected the 30 mfd capacitor but again did not have any voltage on the screen grids, and lost all voltage when I connected a jumper across the speaker choke. I should make note that although I wasn’t receiving any voltage there was a hum coming through the speaker, both before and after disconnecting the 30 mfd cap....i.e. when jumper is across choke.
::I am going to give you a run down of the electrolytic cap connections just in case I do have connections wrong.
::
::Negatives of 30 mfd, 20 mfd, and 5 mfd joined together.....lead from them going to pin1(sh), to pin 3(g3), to pin 5(k) of 6SK7. Then through a .06uf capacitor to a connection located on bottom right corner of the third I.F Transformer which goes to ground through a series of resistors.
::
::Positive of 30 mfd elec. Cap connected to pin 4(g2) of 6F6 to pin 4(g2) of 6AD7.....plus others.
::
::Positive of 20 mfd elect cap going to a connector on the splitter resistor plus pin 6(g2) 6SK7 and pin 4(g2) 6SA7...plus others.
::
::Positive of 5 mfd elect. Cap to anodes of 6AD7 and 6R7, etc.
::
::Negative of 100 mfd and 40 mfd joined......connected to end of splitter resistor and then to power transformer....also connected to pin 5(g) 6F6...plus others.
::
::Positive of 100 mfd connected to end of tone control and I’m assuming it’s the negative end....also connected to pin 3(g3) 6SK7... and others.
::
::Positive of 40 mfd connected to end of splitter choke.....from splitter choke to pin 2(f+) 5U4.
::
::If you’re not discouraged Doc, I’m won’t be either.
::
::Regards
::
::
:::Job,
:::
:::If jumpering across the choke killed the voltage coming into the choke (killed anode voltage on the 6F6 & 6AD7) then there has to be a short on the out side of the choke. A suspect is the 30mfd cap between the choke out lead and chassis. If you replaced the power supply caps with individual caps, did you completely isolate the original cap from the circuit and observe polarity of the replacements? Generally the metal shell of a cap is the negative lead, the other lead positive. May try disconnecting the 30 mfd cap from the circuit leaving all other wires connected to each other and try powering up again. Check your wiring also with the schematic.
:::
:::Radiodoc
:::************
:::
:::
::::Doc-----I followed your instructions and measured voltage going into choke...270v.....no voltage measured coming out of choke. Connected jumper leads across choke but did not receive any voltage on pin 4 of 6F6 tube. Actually I lost voltage on the anodes of 6F6 and 6SK7 while being connected across the choke.....don’t know what this all means. Will wait for further instructions.
::::Regards
::::
::::
:::::Job,
:::::
:::::With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
:::::
:::::Radiodoc
:::::************
:::::
:::::
::::::
::::::Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
::::::Thanks
::::::
::::::
::::::
:::::::Job,
:::::::
:::::::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
:::::::
:::::::Radiodoc
:::::::***********
:::::::
:::::::
:::::::::Job,
::::::::
::::::::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
::::::::Regards
::::::::
::::::::
:::::::::
:::::::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
:::::::::
:::::::::Radiodoc
:::::::::************
:::::::::
:::::::::
::::::::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
::::::::::I will wait for further instructions to determine what is wrong with this radio.
::::::::::Thanks
::::::::::
::::::::::::Job,
::::::::::::
::::::::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
::::::::::::
::::::::::::Radiodoc
::::::::::::**********
::::::::::::
:::::::::::Job,
:::::::::::
:::::::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
:::::::::::
:::::::::::Radiodoc
:::::::::::***********
:::::::::::
::::::::::::
:::::::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:::::::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
I’ll await for your analysis of this information.
Regards
::Job,
::
::Lift (unsolder) the out lead of the speaker choke. Try measuring for voltage then. If still no voltage then the problem may be the choke is shorted to the speaker frame and chassis/ground somehow.
::
::Radiodoc
::************
:
:Job,
:
:I should have said measure for voltage from the choke out lead.
:
:Radiodoc
:*************
:
::
::
:::Hi Doc-----First, the old electrolytic cap containers are isolated from the circuit. All new caps were installed and to the best of my knowledge polarity have been followed and I have checked all connections once more.
:::I disconnected the 30 mfd capacitor but again did not have any voltage on the screen grids, and lost all voltage when I connected a jumper across the speaker choke. I should make note that although I wasn’t receiving any voltage there was a hum coming through the speaker, both before and after disconnecting the 30 mfd cap....i.e. when jumper is across choke.
:::I am going to give you a run down of the electrolytic cap connections just in case I do have connections wrong.
:::
:::Negatives of 30 mfd, 20 mfd, and 5 mfd joined together.....lead from them going to pin1(sh), to pin 3(g3), to pin 5(k) of 6SK7. Then through a .06uf capacitor to a connection located on bottom right corner of the third I.F Transformer which goes to ground through a series of resistors.
:::
:::Positive of 30 mfd elec. Cap connected to pin 4(g2) of 6F6 to pin 4(g2) of 6AD7.....plus others.
:::
:::Positive of 20 mfd elect cap going to a connector on the splitter resistor plus pin 6(g2) 6SK7 and pin 4(g2) 6SA7...plus others.
:::
:::Positive of 5 mfd elect. Cap to anodes of 6AD7 and 6R7, etc.
:::
:::Negative of 100 mfd and 40 mfd joined......connected to end of splitter resistor and then to power transformer....also connected to pin 5(g) 6F6...plus others.
:::
:::Positive of 100 mfd connected to end of tone control and I’m assuming it’s the negative end....also connected to pin 3(g3) 6SK7... and others.
:::
:::Positive of 40 mfd connected to end of splitter choke.....from splitter choke to pin 2(f+) 5U4.
:::
:::If you’re not discouraged Doc, I’m won’t be either.
:::
:::Regards
:::
:::
::::Job,
::::
::::If jumpering across the choke killed the voltage coming into the choke (killed anode voltage on the 6F6 & 6AD7) then there has to be a short on the out side of the choke. A suspect is the 30mfd cap between the choke out lead and chassis. If you replaced the power supply caps with individual caps, did you completely isolate the original cap from the circuit and observe polarity of the replacements? Generally the metal shell of a cap is the negative lead, the other lead positive. May try disconnecting the 30 mfd cap from the circuit leaving all other wires connected to each other and try powering up again. Check your wiring also with the schematic.
::::
::::Radiodoc
::::************
::::
::::
:::::Doc-----I followed your instructions and measured voltage going into choke...270v.....no voltage measured coming out of choke. Connected jumper leads across choke but did not receive any voltage on pin 4 of 6F6 tube. Actually I lost voltage on the anodes of 6F6 and 6SK7 while being connected across the choke.....don’t know what this all means. Will wait for further instructions.
:::::Regards
:::::
:::::
::::::Job,
::::::
::::::With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
::::::
::::::Radiodoc
::::::************
::::::
::::::
:::::::
:::::::Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
:::::::Thanks
:::::::
:::::::
:::::::
::::::::Job,
::::::::
::::::::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
::::::::
::::::::Radiodoc
::::::::***********
::::::::
::::::::
::::::::::Job,
:::::::::
:::::::::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
:::::::::Regards
:::::::::
:::::::::
::::::::::
::::::::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
::::::::::
::::::::::Radiodoc
::::::::::************
::::::::::
::::::::::
:::::::::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
:::::::::::I will wait for further instructions to determine what is wrong with this radio.
:::::::::::Thanks
:::::::::::
:::::::::::::Job,
:::::::::::::
:::::::::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
:::::::::::::
:::::::::::::Radiodoc
:::::::::::::**********
:::::::::::::
::::::::::::Job,
::::::::::::
::::::::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
::::::::::::
::::::::::::Radiodoc
::::::::::::***********
::::::::::::
:::::::::::::
::::::::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::::::::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
Your test has shown we do not have a shorted speaker choke to speaker frame to ground. There is some sort of a short on the out side of the choke killing the B+ voltage. Leave the out lead of the choke disconnected. Measure the resistance from the point where the choke out lead was connected to ground/chassis. The resistance reading should be fairly high. A low resistance reading will indicate a short or almost so to ground which would kill the B+ on that side of the choke. If you get a low reading, start from the out of the choke and check the wiring closely going away from the choke, especially where new caps were installed for shorts to ground such as excess component leads touching ground or where solder has bridged between a terminal strip and chassis or against other solder terminals, etc. One other thing, I don't know what type wire is used in the radio, possibly the old rubber covered wire that flakes off with age. Check the B+ (red?) and anode (blue?)wires out of the 3rd IF transformer where they pass thru the chassis to make sure they are not shorting to the chassis/ground.
Radiodoc
************
:Doc------I carried out your instructions re testing the speaker choke and did receive voltage from the “out lead” of the speaker choke. With the variac set at 90 volts all the voltages were basically the same for the input and output of the speaker choke...360vdc. The anodes also had readings of 360vdc with variac set at 90v...voltages seemed to be high so I did not increase variac to 120 volts.....still no voltage on screen grids of 6F6 and 6AD7.
:I’ll await for your analysis of this information.
:Regards
:
:
:::Job,
:::
:::Lift (unsolder) the out lead of the speaker choke. Try measuring for voltage then. If still no voltage then the problem may be the choke is shorted to the speaker frame and chassis/ground somehow.
:::
:::Radiodoc
:::************
::
::Job,
::
::I should have said measure for voltage from the choke out lead.
::
::Radiodoc
::*************
::
:::
:::
::::Hi Doc-----First, the old electrolytic cap containers are isolated from the circuit. All new caps were installed and to the best of my knowledge polarity have been followed and I have checked all connections once more.
::::I disconnected the 30 mfd capacitor but again did not have any voltage on the screen grids, and lost all voltage when I connected a jumper across the speaker choke. I should make note that although I wasn’t receiving any voltage there was a hum coming through the speaker, both before and after disconnecting the 30 mfd cap....i.e. when jumper is across choke.
::::I am going to give you a run down of the electrolytic cap connections just in case I do have connections wrong.
::::
::::Negatives of 30 mfd, 20 mfd, and 5 mfd joined together.....lead from them going to pin1(sh), to pin 3(g3), to pin 5(k) of 6SK7. Then through a .06uf capacitor to a connection located on bottom right corner of the third I.F Transformer which goes to ground through a series of resistors.
::::
::::Positive of 30 mfd elec. Cap connected to pin 4(g2) of 6F6 to pin 4(g2) of 6AD7.....plus others.
::::
::::Positive of 20 mfd elect cap going to a connector on the splitter resistor plus pin 6(g2) 6SK7 and pin 4(g2) 6SA7...plus others.
::::
::::Positive of 5 mfd elect. Cap to anodes of 6AD7 and 6R7, etc.
::::
::::Negative of 100 mfd and 40 mfd joined......connected to end of splitter resistor and then to power transformer....also connected to pin 5(g) 6F6...plus others.
::::
::::Positive of 100 mfd connected to end of tone control and I’m assuming it’s the negative end....also connected to pin 3(g3) 6SK7... and others.
::::
::::Positive of 40 mfd connected to end of splitter choke.....from splitter choke to pin 2(f+) 5U4.
::::
::::If you’re not discouraged Doc, I’m won’t be either.
::::
::::Regards
::::
::::
:::::Job,
:::::
:::::If jumpering across the choke killed the voltage coming into the choke (killed anode voltage on the 6F6 & 6AD7) then there has to be a short on the out side of the choke. A suspect is the 30mfd cap between the choke out lead and chassis. If you replaced the power supply caps with individual caps, did you completely isolate the original cap from the circuit and observe polarity of the replacements? Generally the metal shell of a cap is the negative lead, the other lead positive. May try disconnecting the 30 mfd cap from the circuit leaving all other wires connected to each other and try powering up again. Check your wiring also with the schematic.
:::::
:::::Radiodoc
:::::************
:::::
:::::
::::::Doc-----I followed your instructions and measured voltage going into choke...270v.....no voltage measured coming out of choke. Connected jumper leads across choke but did not receive any voltage on pin 4 of 6F6 tube. Actually I lost voltage on the anodes of 6F6 and 6SK7 while being connected across the choke.....don’t know what this all means. Will wait for further instructions.
::::::Regards
::::::
::::::
:::::::Job,
:::::::
:::::::With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
:::::::
:::::::Radiodoc
:::::::************
:::::::
:::::::
::::::::
::::::::Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
::::::::Thanks
::::::::
::::::::
::::::::
:::::::::Job,
:::::::::
:::::::::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
:::::::::
:::::::::Radiodoc
:::::::::***********
:::::::::
:::::::::
:::::::::::Job,
::::::::::
::::::::::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
::::::::::Regards
::::::::::
::::::::::
:::::::::::
:::::::::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
:::::::::::
:::::::::::Radiodoc
:::::::::::************
:::::::::::
:::::::::::
::::::::::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
::::::::::::I will wait for further instructions to determine what is wrong with this radio.
::::::::::::Thanks
::::::::::::
::::::::::::::Job,
::::::::::::::
::::::::::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
::::::::::::::
::::::::::::::Radiodoc
::::::::::::::**********
::::::::::::::
:::::::::::::Job,
:::::::::::::
:::::::::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
:::::::::::::
:::::::::::::Radiodoc
:::::::::::::***********
:::::::::::::
::::::::::::::
:::::::::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:::::::::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
5U4..pin 2(f+)=204v, pin 8(f-)=204v
6F6..pin 1(sh)=42v, pin 2(h)=42v, pin 3(a)=200v, pin 4(g2)=42v, pin 7(h)=42v, pin 8(k)=42v
6AD7..pin 2(h)=42v, pin 3(a)=206v, pin 4(g2)=42v, pin 6(a”)=33v, pin 7(h)=42v, pin 8(k)=42v
6SK7..pin 1(sh)=42v, pin 2(h)=42v, pin 3(g3)=40v, etc, etc, etc.
All of the other tubes are giving similar readings
I will again leave this for your analysis...I do appreciate your assistance.
Regards
:Job,
:
:Your test has shown we do not have a shorted speaker choke to speaker frame to ground. There is some sort of a short on the out side of the choke killing the B+ voltage. Leave the out lead of the choke disconnected. Measure the resistance from the point where the choke out lead was connected to ground/chassis. The resistance reading should be fairly high. A low resistance reading will indicate a short or almost so to ground which would kill the B+ on that side of the choke. If you get a low reading, start from the out of the choke and check the wiring closely going away from the choke, especially where new caps were installed for shorts to ground such as excess component leads touching ground or where solder has bridged between a terminal strip and chassis or against other solder terminals, etc. One other thing, I don't know what type wire is used in the radio, possibly the old rubber covered wire that flakes off with age. Check the B+ (red?) and anode (blue?)wires out of the 3rd IF transformer where they pass thru the chassis to make sure they are not shorting to the chassis/ground.
:
:Radiodoc
:************
:
:
::Doc------I carried out your instructions re testing the speaker choke and did receive voltage from the “out lead” of the speaker choke. With the variac set at 90 volts all the voltages were basically the same for the input and output of the speaker choke...360vdc. The anodes also had readings of 360vdc with variac set at 90v...voltages seemed to be high so I did not increase variac to 120 volts.....still no voltage on screen grids of 6F6 and 6AD7.
::I’ll await for your analysis of this information.
::Regards
::
::
::::Job,
::::
::::Lift (unsolder) the out lead of the speaker choke. Try measuring for voltage then. If still no voltage then the problem may be the choke is shorted to the speaker frame and chassis/ground somehow.
::::
::::Radiodoc
::::************
:::
:::Job,
:::
:::I should have said measure for voltage from the choke out lead.
:::
:::Radiodoc
:::*************
:::
::::
::::
:::::Hi Doc-----First, the old electrolytic cap containers are isolated from the circuit. All new caps were installed and to the best of my knowledge polarity have been followed and I have checked all connections once more.
:::::I disconnected the 30 mfd capacitor but again did not have any voltage on the screen grids, and lost all voltage when I connected a jumper across the speaker choke. I should make note that although I wasn’t receiving any voltage there was a hum coming through the speaker, both before and after disconnecting the 30 mfd cap....i.e. when jumper is across choke.
:::::I am going to give you a run down of the electrolytic cap connections just in case I do have connections wrong.
:::::
:::::Negatives of 30 mfd, 20 mfd, and 5 mfd joined together.....lead from them going to pin1(sh), to pin 3(g3), to pin 5(k) of 6SK7. Then through a .06uf capacitor to a connection located on bottom right corner of the third I.F Transformer which goes to ground through a series of resistors.
:::::
:::::Positive of 30 mfd elec. Cap connected to pin 4(g2) of 6F6 to pin 4(g2) of 6AD7.....plus others.
:::::
:::::Positive of 20 mfd elect cap going to a connector on the splitter resistor plus pin 6(g2) 6SK7 and pin 4(g2) 6SA7...plus others.
:::::
:::::Positive of 5 mfd elect. Cap to anodes of 6AD7 and 6R7, etc.
:::::
:::::Negative of 100 mfd and 40 mfd joined......connected to end of splitter resistor and then to power transformer....also connected to pin 5(g) 6F6...plus others.
:::::
:::::Positive of 100 mfd connected to end of tone control and I’m assuming it’s the negative end....also connected to pin 3(g3) 6SK7... and others.
:::::
:::::Positive of 40 mfd connected to end of splitter choke.....from splitter choke to pin 2(f+) 5U4.
:::::
:::::If you’re not discouraged Doc, I’m won’t be either.
:::::
:::::Regards
:::::
:::::
::::::Job,
::::::
::::::If jumpering across the choke killed the voltage coming into the choke (killed anode voltage on the 6F6 & 6AD7) then there has to be a short on the out side of the choke. A suspect is the 30mfd cap between the choke out lead and chassis. If you replaced the power supply caps with individual caps, did you completely isolate the original cap from the circuit and observe polarity of the replacements? Generally the metal shell of a cap is the negative lead, the other lead positive. May try disconnecting the 30 mfd cap from the circuit leaving all other wires connected to each other and try powering up again. Check your wiring also with the schematic.
::::::
::::::Radiodoc
::::::************
::::::
::::::
:::::::Doc-----I followed your instructions and measured voltage going into choke...270v.....no voltage measured coming out of choke. Connected jumper leads across choke but did not receive any voltage on pin 4 of 6F6 tube. Actually I lost voltage on the anodes of 6F6 and 6SK7 while being connected across the choke.....don’t know what this all means. Will wait for further instructions.
:::::::Regards
:::::::
:::::::
::::::::Job,
::::::::
::::::::With your meter set to measure DC voltage, (with the radio turned on) measure for voltage on the input lead of the speaker choke coil and then measure for voltage on the output lead of the speaker choke coil. The meter minus lead goes to ground/chassis. If there is voltage on the input lead of the choke but none on the output lead of the choke, the speaker choke may be opening up when current is being drawn thru it (tubes start drawing current). If there is voltage in but none out, may try using a clip junper lead and jump across the speaker choke and measure for voltage on the pin 4 of the 6F6.
::::::::
::::::::Radiodoc
::::::::************
::::::::
::::::::
:::::::::
:::::::::Hi Doc------I followed your instructions and connected two 1N4007 diodes to the pins of tube 5U4 as per instructions. I did not receive any voltage different than when using the 5U4 tube. I rechecked the continuity of field coil, etc., and again all was o.k. Do you have any other suggestions?
:::::::::Thanks
:::::::::
:::::::::
:::::::::
::::::::::Job,
::::::::::
::::::::::Just curious...Have you substituted another good 5U4? In lieu of having another tube and possibly having some solid state rectifiers lying around, substitute a couple for the sections of the tube. A 1N4007 (1 amp 1000 volt) or equivalent from each plate lead to pin 2 or 8 (where the wire to the link and filter caps is connected) of the rectifier socket. The bar or band marking on the SS rectifier is the plus and is the lead(s) that go to pin 2 or 8. You can use clip leads to do this or just solder to the socket tabs. Try powering up with the 5U4 removed.
::::::::::
::::::::::Radiodoc
::::::::::***********
::::::::::
::::::::::
::::::::::::Job,
:::::::::::
:::::::::::Doc-----I have checked items as per your instructions and all checks seem to be O.K...I have checked resistors and did replace one but others were all within range. I have looked for shorts but can’t find any so I’m at a lost as to what is going on. I will wait for further advise.
:::::::::::Regards
:::::::::::
:::::::::::
::::::::::::
::::::::::::Firstly, the transformer high voltage centertap DOES NOT go directly to ground. The first electrolytic cap's (denoted by half moon on schematic)positive lead goes to the filament (2 or 8) of the 5U4 thru the link and also connects to the input lead of the speaker choke. Its negative lead goes to the centertap lead (NOT directly to chassis or ground). The negative lead of the 100mfd cap goes to the centertap (because there is -22 volts there) and the plus lead goes to chassis/ground. The electrolytic on the other side of the speaker choke has its plus connected to the choke and its minus to the chassis/ground. If you had continuity from the 5U4 to the G2 pin of the 6F6, check the resistors from the transformer centertap to chassis/ground to make sure none are open or have changed greatly in value. Also a check (with power off) of the resistance from pin 4 of the 6F6 to ground/chassis will let us know if there is a short on that B+ line to ground.
::::::::::::
::::::::::::Radiodoc
::::::::::::************
::::::::::::
::::::::::::
:::::::::::::Doc-------I have checked continuity as per your instructions and all checked out O.K..I should point out that this is one of the first radios I started to work on when I began this hobby and to be truthful it scared me to death so I quit and worked on less complicated ones. However, I had disconnected the electrolytic capacitors without noting where they should be connected, so when I went back to this radio I had problems trying to figure out just where everything was to be connected but I do believe I have it right but again maybe something could be connected wrong. Is the positive connection of the 100uf capacitor actually going to ground???
:::::::::::::I will wait for further instructions to determine what is wrong with this radio.
:::::::::::::Thanks
:::::::::::::
:::::::::::::::Job,
:::::::::::::::
:::::::::::::::Check for continuity from pin 2 or 8 of the 5U4 to and thru the "link" and on thru the speaker field coil. You may have a bad speaker field coil or a bad wiring connection.
:::::::::::::::
:::::::::::::::Radiodoc
:::::::::::::::**********
:::::::::::::::
::::::::::::::Job,
::::::::::::::
::::::::::::::And continue on from the out of the speaker field on to the G2 pins of the 6F6 and 6Ad7
::::::::::::::
::::::::::::::Radiodoc
::::::::::::::***********
::::::::::::::
:::::::::::::::
::::::::::::::::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::::::::::::::::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
The 42 volts is everywhere. I noted that the 6F6 screen measured 42 volts also. At the moment I don't understand why we are measuring 42 volts on points that are (supposed to be) grounded. I'll study your measurements tonight and try to figure out something. Recheck resistors R31 & 32 (believe those are the numbers as my print is not too good) and make SURE one end of the 22 ohm resistor is grounded. I have had trouble in the past using a DVM measuring resistors with them reading good only when using an old analog VOM found them open or very high in resistance. If unsure may try clipping a 500 ohm resistor from a good chassis ground point to the centertap of the high voltage winding and see what happens.
Radiodoc
************
:I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
I am trying to figure out what I did to create the extra voltage and I think it was when I disconnected the ground of the 40mfd and 100mfd elect. capacitors from the former elect. Cap container. At this time the negative ends are a “solder glob” going nowhere. I attached this negative glob to the chassis but lost the screen grid again.....sooo, right now the negative of 40uf and 100uf is exactly as it is shown on the schematic....but not attached to the chassis. I’m trusting that one of the connections to the “negative glob” is connected to ground......see I have already created new terminology.
I wish I had more information to give you so that it would help you to figure out what is going on here....I do believe that the “final” analysis will show that I..or the previous owner.. have connected something wrong.
Regards
:Job,
:
:The 42 volts is everywhere. I noted that the 6F6 screen measured 42 volts also. At the moment I don't understand why we are measuring 42 volts on points that are (supposed to be) grounded. I'll study your measurements tonight and try to figure out something. Recheck resistors R31 & 32 (believe those are the numbers as my print is not too good) and make SURE one end of the 22 ohm resistor is grounded. I have had trouble in the past using a DVM measuring resistors with them reading good only when using an old analog VOM found them open or very high in resistance. If unsure may try clipping a 500 ohm resistor from a good chassis ground point to the centertap of the high voltage winding and see what happens.
:
:Radiodoc
:************
:
:
::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
The negatives of the the 40mf and 100mf cap should connect with the centertap of the high voltage winding and also connect to R21 in the metal covered resistor mounted on the chassis. From the junction of the two caps you should measure around 200 or so ohms resistance to a good ground connection on the chassis. If the power supply were operating properly, you should measure around minus 20 or so volts at the junction of the 40 & 100 mfd caps to chassis.
Radiodoc
***********
:Doc, Is R21 and R22 part of the divider resistors, or whatever?....it’s a metal strip...attached to the bottom of the chassis... with six connectors but one connection is not in use...I believe I was calling them splitter resistors but I have also invented other names for some of those items.....I had difficulty trying to identify the particular resistors you mentioned but the readings I got were within the range on the schematic. I did connect the 500 ohm resistor but no change in the voltage.
:I am trying to figure out what I did to create the extra voltage and I think it was when I disconnected the ground of the 40mfd and 100mfd elect. capacitors from the former elect. Cap container. At this time the negative ends are a “solder glob” going nowhere. I attached this negative glob to the chassis but lost the screen grid again.....sooo, right now the negative of 40uf and 100uf is exactly as it is shown on the schematic....but not attached to the chassis. I’m trusting that one of the connections to the “negative glob” is connected to ground......see I have already created new terminology.
:I wish I had more information to give you so that it would help you to figure out what is going on here....I do believe that the “final” analysis will show that I..or the previous owner.. have connected something wrong.
:Regards
:
:
:
:
::Job,
::
::The 42 volts is everywhere. I noted that the 6F6 screen measured 42 volts also. At the moment I don't understand why we are measuring 42 volts on points that are (supposed to be) grounded. I'll study your measurements tonight and try to figure out something. Recheck resistors R31 & 32 (believe those are the numbers as my print is not too good) and make SURE one end of the 22 ohm resistor is grounded. I have had trouble in the past using a DVM measuring resistors with them reading good only when using an old analog VOM found them open or very high in resistance. If unsure may try clipping a 500 ohm resistor from a good chassis ground point to the centertap of the high voltage winding and see what happens.
::
::Radiodoc
::************
::
::
:::I need help with this complicated chassis,,,complicated for me, that is. All of the tube filaments are reading 5.1 Vac, except for the rectifier tube 5U4 which reads 3.8Vac. I am only getting readings on the rectifier tube and the two output tubes...readings are as follows:...tube 5U4, across filament..3.8Vac, pin 2(F+)..228Vdc, pin 8(F-)..263Vdc. Tube 6F6,across filaments..5.1Vac, pin 3(a)..280Vdc, pin 4(g2)..0Vdc. Tube 6AD7, across filaments..5.1Vac, pin 3(a)..284Vdc, pin 4(g2) 0Vdc. As noted there isn't any screen voltage.....The output transformer seems to be o.k since I'm picking up sound from the grid of 6AD7.
:::All of the electrolytic caps are replaced.....This schematic is a little clearer than the one in Nostolgia...http://www.radiomuseum.org/r/rca_rc531_q44.html.....I would appreciate your assistance.
No time for textual fill in tonight, but reference the marked up schema in the interim, and plunge a negative DC metering probe into the ground at the center of the 4 power resistors used for negative voltage derivation and a voltage divider to the right create the 100VDC B+ level .
Power up the set and give us the 2 negative voltage readings to the left and then confirm the ~ 100 VDC reading to the right and the sub B+ level over to the far right.
Schema …J-pegged …so mag it on up in size….
73's de Edd
Measuring from the negative connection of those two caps to ground I got a reading of 300 ohms. The voltage reading from the negative connection to chassis gave a reading of minus 49 volts.
Edd, I did not receive any voltage readings to the left of the ground connection on that metal strip. On the right I read minus 7 volts and the far right read minus 48 volts. Those readings were with the negative probe of the meter at the negative center of the metal strip.
Making the same measurements with the meter negative probe at the connection of the 40mfd and 100mfd I read 42 volts to the right and o (zero) volts to the far right.
There are 6 connections on that metal strip and I took voltage readings using the negative connections of the 40 and 100 mfd caps for my meter negative probe. For your information the readings are as follows, from left to right:
48v, 48v, 48v, 48v, 42v, 0 volts.
I am emailing a photo to you both showing this resistor metal strip....also a question.....can the immediate connection of the 40mfd and the 100mfd be used as common ground?
Thanks to you both and my regards.
Job
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:No time for textual fill in tonight, but reference the marked up schema in the interim, and plunge a negative DC metering probe into the ground at the center of the 4 power resistors used for negative voltage derivation and a voltage divider to the right create the 100VDC B+ level .
:
:Power up the set and give us the 2 negative voltage readings to the left and then confirm the ~ 100 VDC reading to the right and the sub B+ level over to the far right.
:
:Schema …J-pegged …so mag it on up in size….
:
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:73's de Edd
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What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
Thassist
73's de Edd
::Schema …J-pegged …so you may have to mag it on up in size….
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I have enabled my email address.
Radiodoc
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:What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
:
:The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
:So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
:
:
:Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
:The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
:
:
:
:Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
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:Thassist
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:73's de Edd
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:::Schema …J-pegged …so you may have to mag it on up in size….
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1 and 2 = 240 ohms....1 and 3 = 282 ohms... 1 and 4 = 5170 ohms... 1 and 5 = 1272 ohms...1 and 6 ... = 1275 ohms
2 and 3 = 42 ohms... 2 and 4 = 4930 ohms... 2 and 5 = 1052 ohms... 2 and 6 = 44 ohms
3 and 4 = 4890 ohms... 3 and 5 = 991 0hms... 3 and 6 = 0.8 ohms
4 and 5 = 4600 ohms... 4 and 6 = 4890 ohms
5 and 6 = 990 ohms
The reading from the positive of C68 to the right of R42 is 0.1 ohms......the other side of this resistor and the positive of C68 gave a reading of 990 ohms.
I know that the above is probably confusing so feel free to ask me to retest. Now for another question. I’m assuming that those resistors are in series and therefore would only need 5 connecting points for 4 resistors, which is showing in the schematics. However, in reality there is a sixth connector on this metal strip and this confuses me. Are the resistors connected to this grounding terminal?
Regards
:Job,
:
:I have enabled my email address.
:
:Radiodoc
:************
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::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
::
::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
::
::
::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
::
::
::
::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
::
::
::Thassist
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::73's de Edd
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::::Schema …J-pegged …so you may have to mag it on up in size….
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::
What is your resistance measurement from the positive of C68 to good chassis ground?
Radiodoc
***********
:Gentlemen, I have resistor readings for you and because I’m not sure where the beginning and endings are for the resistors in the middle of this metal strip, I am numbering the connector points from one to six...looking at the schematic from left to right.
:
:1 and 2 = 240 ohms....1 and 3 = 282 ohms... 1 and 4 = 5170 ohms... 1 and 5 = 1272 ohms...1 and 6 ... = 1275 ohms
:2 and 3 = 42 ohms... 2 and 4 = 4930 ohms... 2 and 5 = 1052 ohms... 2 and 6 = 44 ohms
:3 and 4 = 4890 ohms... 3 and 5 = 991 0hms... 3 and 6 = 0.8 ohms
:4 and 5 = 4600 ohms... 4 and 6 = 4890 ohms
:5 and 6 = 990 ohms
:
:The reading from the positive of C68 to the right of R42 is 0.1 ohms......the other side of this resistor and the positive of C68 gave a reading of 990 ohms.
:
:I know that the above is probably confusing so feel free to ask me to retest. Now for another question. I’m assuming that those resistors are in series and therefore would only need 5 connecting points for 4 resistors, which is showing in the schematics. However, in reality there is a sixth connector on this metal strip and this confuses me. Are the resistors connected to this grounding terminal?
:Regards
:
:
:
:
::Job,
::
::I have enabled my email address.
::
::Radiodoc
::************
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:::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
:::
:::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
:::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
:::
:::
:::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
:::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
:::
:::
:::
:::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
:::
:::
:::Thassist
:::
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:::
:::
:::73's de Edd
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:::::Schema …J-pegged …so you may have to mag it on up in size….
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From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
Radiodoc
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:What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
:
:The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
:So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
:
:
:Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
:The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
:
:
:
:Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
:
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:Thassist
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:73's de Edd
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:::Schema …J-pegged …so you may have to mag it on up in size….
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:From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
de Edd
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:Radiodoc
:************
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::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
::
::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
::
::
::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
::
::
::
::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
::
::
::Thassist
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::73's de Edd
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::
::::Schema …J-pegged …so you may have to mag it on up in size….
::::
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::::
::::
::::
::
::
::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
:
:Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
:de Edd
73's de Edd
::
::Radiodoc
::************
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:::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
:::
:::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
:::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
:::
:::
:::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
:::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
:::
:::
:::
:::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
:::
:::
:::Thassist
:::
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:::
:::
:::
:::
:::73's de Edd
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:::::Schema …J-pegged …so you may have to mag it on up in size….
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I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
Radiodoc
************
:::Edd,
:::
:::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
::
::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
::de Edd
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:73's de Edd
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:::Radiodoc
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::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
::::
::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
::::
::::
::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
::::
::::
::::
::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
::::
::::
::::Thassist
::::
::::
::::
::::
::::
::::
::::73's de Edd
::::
::::
::::
::::
::::
::::
::::
::::::Schema …J-pegged …so you may have to mag it on up in size….
::::::
::::::
::::::
::::::
::::::
::::
Since my last message I almost started the Third World War. I had disconnected some leads to connectors on the voltage divider to recheck resistance and I was foolish enough to put power on the radio.....the 100 mfd capacitor blew like a bomb. After the fallout had settled I replaced another new one. I am confused as to what is connected to the positive of this 100mfd electrolytic capacitor since it goes to ground but I noticed that the outlead of the speaker choke is connected to the positive lead. Do this seem right to you guys????
Oh yes, I almost forgot to tell you, I have lost the 42 voltage readings and we are now back to voltage being on the anodes of 6F6 and 6AD7 only......not sure if this is to our advantage or not.
Regards
:Edd,
:
:I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
:
:Radiodoc
:************
:
:
::::Edd,
::::
::::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
:::
:::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
:::de Edd
::
::
::
::
::
::
::
::
::
::
::
::
::
::
::73's de Edd
::
::
::
::
::
::
::
::
::
::
::
::::
::::Radiodoc
::::************
::::
::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
:::::
:::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
:::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
:::::
:::::
:::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
:::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
:::::
:::::
:::::
:::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
:::::
:::::
:::::Thassist
:::::
:::::
:::::
:::::
:::::
:::::
:::::73's de Edd
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::::Schema …J-pegged …so you may have to mag it on up in size….
:::::::
:::::::
:::::::
:::::::
:::::::
:::::
If you measure zero ohms from the positive lead of capacitor 68 and the choke out lead, then you have a short there on the lower B+. The minus lead of that cap goes to the chassis. You will need to check out the circuit from the out lead of the choke and its branches to other tubes to try to find the short. Look for obvious things such as globs of solder between terminal strip terminals and chassis, ends of wire leads shorting to chassis, insulation off wires, etc.
Radiodoc
************
:Sorry about the resistance check Doc. Anyhow I took a couple of readings of the outlead of the speaker choke to chassis but I’m still not sure where I should be going for chassis. Anyhow, from speaker outlead to negative junction of 40mfd and 100mfd caps...288 ohms.......speaker outlead to negative of Cap 68 (30mfd)......zero ohms.......speaker outlead to terminal point on metal chassis...zero ohms.
:Since my last message I almost started the Third World War. I had disconnected some leads to connectors on the voltage divider to recheck resistance and I was foolish enough to put power on the radio.....the 100 mfd capacitor blew like a bomb. After the fallout had settled I replaced another new one. I am confused as to what is connected to the positive of this 100mfd electrolytic capacitor since it goes to ground but I noticed that the outlead of the speaker choke is connected to the positive lead. Do this seem right to you guys????
:Oh yes, I almost forgot to tell you, I have lost the 42 voltage readings and we are now back to voltage being on the anodes of 6F6 and 6AD7 only......not sure if this is to our advantage or not.
:Regards
:
:
:
:
::Edd,
::
::I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
::
::Radiodoc
::************
::
::
:::::Edd,
:::::
:::::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
::::
::::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
::::de Edd
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::73's de Edd
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::::
:::::Radiodoc
:::::************
:::::
:::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
::::::
::::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
::::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
::::::
::::::
::::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
::::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
::::::
::::::
::::::
::::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
::::::
::::::
::::::Thassist
::::::
::::::
::::::
::::::
::::::
::::::
::::::73's de Edd
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::::Schema …J-pegged …so you may have to mag it on up in size….
::::::::
::::::::
::::::::
::::::::
::::::::
::::::
Regards
:Job,
:
:If you measure zero ohms from the positive lead of capacitor 68 and the choke out lead, then you have a short there on the lower B+. The minus lead of that cap goes to the chassis. You will need to check out the circuit from the out lead of the choke and its branches to other tubes to try to find the short. Look for obvious things such as globs of solder between terminal strip terminals and chassis, ends of wire leads shorting to chassis, insulation off wires, etc.
:
:Radiodoc
:************
:
:
::Sorry about the resistance check Doc. Anyhow I took a couple of readings of the outlead of the speaker choke to chassis but I’m still not sure where I should be going for chassis. Anyhow, from speaker outlead to negative junction of 40mfd and 100mfd caps...288 ohms.......speaker outlead to negative of Cap 68 (30mfd)......zero ohms.......speaker outlead to terminal point on metal chassis...zero ohms.
::Since my last message I almost started the Third World War. I had disconnected some leads to connectors on the voltage divider to recheck resistance and I was foolish enough to put power on the radio.....the 100 mfd capacitor blew like a bomb. After the fallout had settled I replaced another new one. I am confused as to what is connected to the positive of this 100mfd electrolytic capacitor since it goes to ground but I noticed that the outlead of the speaker choke is connected to the positive lead. Do this seem right to you guys????
::Oh yes, I almost forgot to tell you, I have lost the 42 voltage readings and we are now back to voltage being on the anodes of 6F6 and 6AD7 only......not sure if this is to our advantage or not.
::Regards
::
::
::
::
:::Edd,
:::
:::I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
:::
:::Radiodoc
:::************
:::
:::
::::::Edd,
::::::
::::::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
:::::
:::::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
:::::de Edd
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::73's de Edd
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::::
::::::Radiodoc
::::::************
::::::
::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
:::::::
:::::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
:::::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
:::::::
:::::::
:::::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
:::::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
:::::::
:::::::
:::::::
:::::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
:::::::
:::::::
:::::::Thassist
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::73's de Edd
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::::Schema …J-pegged …so you may have to mag it on up in size….
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::
:Since my last message I almost started the Third World War. I had disconnected some leads to connectors on the voltage divider to recheck resistance and I was foolish enough to put power on the radio.....the 100 mfd capacitor blew like a bomb. After the fallout had settled I replaced another new one. I am confused as to what is connected to the positive of this 100mfd electrolytic capacitor since it goes to ground but I noticed that the outlead of the speaker choke is connected to the positive lead. Do this seem right to you guys????
:Oh yes, I almost forgot to tell you, I have lost the 42 voltage readings and we are now back to voltage being on the anodes of 6F6 and 6AD7 only......not sure if this is to our advantage or not.
:Regards
*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>
What is that thing that looks like "link" off of the 5U4 filament? Wouldn't that thing being open lose you the screen Voltage to the output tubes???
Lewis
:
:
:
:
::Edd,
::
::I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
::
::Radiodoc
::************
::
::
:::::Edd,
:::::
:::::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
::::
::::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
::::de Edd
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::73's de Edd
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::
:::::
:::::Radiodoc
:::::************
:::::
:::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
::::::
::::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
::::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
::::::
::::::
::::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
::::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
::::::
::::::
::::::
::::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
::::::
::::::
::::::Thassist
::::::
::::::
::::::
::::::
::::::
::::::
::::::73's de Edd
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::::Schema …J-pegged …so you may have to mag it on up in size….
::::::::
::::::::
::::::::
::::::::
::::::::
::::::
That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
Radiodoc
************
::Sorry about the resistance check Doc. Anyhow I took a couple of readings of the outlead of the speaker choke to chassis but I’m still not sure where I should be going for chassis. Anyhow, from speaker outlead to negative junction of 40mfd and 100mfd caps...288 ohms.......speaker outlead to negative of Cap 68 (30mfd)......zero ohms.......speaker outlead to terminal point on metal chassis...zero ohms.
::Since my last message I almost started the Third World War. I had disconnected some leads to connectors on the voltage divider to recheck resistance and I was foolish enough to put power on the radio.....the 100 mfd capacitor blew like a bomb. After the fallout had settled I replaced another new one. I am confused as to what is connected to the positive of this 100mfd electrolytic capacitor since it goes to ground but I noticed that the outlead of the speaker choke is connected to the positive lead. Do this seem right to you guys????
::Oh yes, I almost forgot to tell you, I have lost the 42 voltage readings and we are now back to voltage being on the anodes of 6F6 and 6AD7 only......not sure if this is to our advantage or not.
::Regards
:
:
:*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>
:
:What is that thing that looks like "link" off of the 5U4 filament? Wouldn't that thing being open lose you the screen Voltage to the output tubes???
:
:Lewis
::
::
::
::
:::Edd,
:::
:::I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
:::
:::Radiodoc
:::************
:::
:::
::::::Edd,
::::::
::::::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
:::::
:::::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
:::::de Edd
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::73's de Edd
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::::
::::::Radiodoc
::::::************
::::::
::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
:::::::
:::::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
:::::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
:::::::
:::::::
:::::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
:::::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
:::::::
:::::::
:::::::
:::::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
:::::::
:::::::
:::::::Thassist
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::73's de Edd
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::::Schema …J-pegged …so you may have to mag it on up in size….
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::
:
:That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
:
:Radiodoc
:************
:
My manic=depressive computer has been commited for a few days, having fallen in to a depressive mood and crashing every few minutes, so I have been out of the loop for a few days. While trying to sort out Job's problem, I started typing when I should have been reading.
Lewis
Doc, I’m probably missing something here but I thought that the out lead from the speaker choke to the positive of 30mfd capacitor would show zero ohms since it is fed directly to the capacitor through the terminals of screen grids 6F6 and 6AD7, without any resistors or capacitors to create resistance.
Regards
::Lewis,
::
::That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
::
::Radiodoc
::************
::
:
:
:My manic=depressive computer has been commited for a few days, having fallen in to a depressive mood and crashing every few minutes, so I have been out of the loop for a few days. While trying to sort out Job's problem, I started typing when I should have been reading.
:Lewis
:
If you will notice on the schematic measuring across the cap 68 (30mf) you are measuring across the lower B+ line. If you get zero or near so Ohms resistance, there is a short which will kill the voltage going to the 6F6 screens (G2) and other points. You will need to trace out the wiring from the out of the choke and any branches from it where voltage goes to try to find the short.
Radiodoc
************
:I’ll reposition this posting.
:
:Doc, I’m probably missing something here but I thought that the out lead from the speaker choke to the positive of 30mfd capacitor would show zero ohms since it is fed directly to the capacitor through the terminals of screen grids 6F6 and 6AD7, without any resistors or capacitors to create resistance.
:Regards
:
:
:
:::Lewis,
:::
:::That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
:::
:::Radiodoc
:::************
:::
::
::
::My manic=depressive computer has been commited for a few days, having fallen in to a depressive mood and crashing every few minutes, so I have been out of the loop for a few days. While trying to sort out Job's problem, I started typing when I should have been reading.
::Lewis
::
When you supplied the resistance readings of the 5 terminal Muter resistor, a quick perusal revealed that there is a short between your 275 VDC supply at the right end of R42 resistor section and ground.
Sooooo to track it down to see where that short is, start by ALWAYS using the specified ground reference of the negative lead of C68 electrolytic so that we will have a uniform ohms ground reference point on later tests.
Your last statement was:
Doc, I’m probably missing something here but I thought that the out lead from the speaker choke to the positive of 30mfd capacitor would show zero ohms since it is fed directly to the capacitor through the terminals of screen grids 6F6 and 6AD7, without any resistors or capacitors to create resistance.
HOT Reference to full schema…which might need a click / on/ magging up ..as its J-pegged for max color rendition.
http://img174.imageshack.us/img174/7964/rcaq44markedupschmaov1.jpg
I think that it is already confirmed that the initial raw B+ has been present at the supply point marked up as reference [A] and made it all of the way up to the plate supplies of the audio out tubes via the output transformer via the broken red line route. Put that path aside, its O.K. and covered.
Now back at initial point [A] it also went to the right and passed thru the link…OK…then it successfully connected into the C82 electrolytic for some filtering and then the B+ then needs to pass thru the speaker field coil and be reduced to the sub B+ level of ~ +275VDC , which then sneaks down and gets a bit further filtering via C68 electrolytic. The sub B+ is then ready to flow up and only make but a few connection nodes to have fed all of the points needing that level of B+, the first one above would be the traveling up the solid red line starting at [AII] and its first stop is the top right end of your R42 section of the Muter resistor where in conjunction with R33 they make a voltage divider pair to derive 100 VDC for a sub- sub B+ level for some specific areas.
Take a further upward path from the resistor and you will see that the next supply point would be the two screens of the output tubes, where I would expect no trouble there, the last route is the one to the left where I abruptly stop at a red dot. That reasoning is because my CD of Riders #12 has cut that schematic into 2 parts and they did not get the entire schematics center portion in the coverage…thus my shaded area of uncertainty. The only other areas that would be tied into that supply would be circuitry to the left of my final red dot. Most all of that probably will be isolated from that bus by 1000’s of ohms of resistive isolation in feeding lesser voltages to the R F and IF frontal circuitry, which would not pull down that voltage significantly if a short was via a resistor…it might smoke low values , however.
I am wanting an initial check of voltage now after all of your different changes , since the last info that I have below on a separate thumbnail shows the reading that you gave that were on the Muter resistor shows a shorting out of the 275 VDC
supply, therefore you should have no +275 VDC now, you have had it, and haven’t had it, at different times of switching around , up to that WW I I I esscccaaapade.
If you still have a short on that line then we would then need to systematically first lift the wiring from the end of the R42 and see if that cleared up the problem, or then find that red supply line where I lost its distribution at the final red dot, and then open that buss line to see if that cleared the short.
Thumbnail of Muters resistances you supplied / vs / schematic supplied values:
73's de Edd
::
::That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
::
::Radiodoc
::************
::
:
:
:My manic=depressive computer has been commited for a few days, having fallen in to a depressive mood and crashing every few minutes, so I have been out of the loop for a few days. While trying to sort out Job's problem, I started typing when I should have been reading.
:Lewis
All:
On that subject, after the electro-shock treatment, I have lost a very useful site, one in Deja Vu, with an old Indian Head TV test pattern. It is more useful for car radios and other radios of a later vintage than this one. Can I get the URL from someone??
TNX, Lewis
:
:All:
:On that subject, after the electro-shock treatment, I have lost a very useful site, one in Deja Vu, with an old Indian Head TV test pattern. It is more useful for car radios and other radios of a later vintage than this one. Can I get the URL from someone??
:TNX, Lewis
:
:
:
::
:::
:::That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
:::
:::Radiodoc
:::************
:::
::
::
::My manic=depressive computer has been commited for a few days, having fallen in to a depressive mood and crashing every few minutes, so I have been out of the loop for a few days. While trying to sort out Job's problem, I started typing when I should have been reading.
::Lewis
:
:
:All:
:On that subject, after the electro-shock treatment, I have lost a very useful site, one in Deja Vu, with an old Indian Head TV test pattern. It is more useful for car radios and other radios of a later vintage than this one. Can I get the URL from someone??
:TNX, Lewis
Lewis: try http://techpreservation.dyndns.org/schematics/
Andy
:
:
:
::
::On that subject, after the electro-shock treatment, I have lost a very useful site, one in Deja Vu, with an old Indian Head TV test pattern. It is more useful for car radios and other radios of a later vintage than this one. Can I get the URL from someone??
::TNX, Lewis
:
:
:Lewis: try http://techpreservation.dyndns.org/schematics/
:Andy
::
Yea, dazzit!!! My computer and I are both getting old and have faulty memories. Thanz to Andy and Tony.
Lewis
::
::
:::
All filaments have voltages and the anodes of 6F6 and 6FD7 are reading 206 volts each.
All voltages are being taken with negative probe of meter on the negative lead of capacitor 68 ( 30mfd )......readings are:
The grids of 6F6 and 6FD7 to ground are zero ohms.
Ground to in lead of speaker choke...190 volts
Ground to out lead of speaker choke is...zero volts
I unsoldered out lead connection to speaker choke......we now have 136 volts on the out lead.
With lead to speaker choke unsoldered....anode of 6F6 is 64 volts and anode of 6AD7 is 165 volts..no voltage on screen grids.
The readings for the resistors on that voltage divider did not change....same resistance.......Looks as if we’re back to square one.
Let me know if you need more readings...however, I’ll continue to look for shorts.
Regards
:Lewis,
:
:That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
:
:Radiodoc
:************
:
:
:::Sorry about the resistance check Doc. Anyhow I took a couple of readings of the outlead of the speaker choke to chassis but I’m still not sure where I should be going for chassis. Anyhow, from speaker outlead to negative junction of 40mfd and 100mfd caps...288 ohms.......speaker outlead to negative of Cap 68 (30mfd)......zero ohms.......speaker outlead to terminal point on metal chassis...zero ohms.
:::Since my last message I almost started the Third World War. I had disconnected some leads to connectors on the voltage divider to recheck resistance and I was foolish enough to put power on the radio.....the 100 mfd capacitor blew like a bomb. After the fallout had settled I replaced another new one. I am confused as to what is connected to the positive of this 100mfd electrolytic capacitor since it goes to ground but I noticed that the outlead of the speaker choke is connected to the positive lead. Do this seem right to you guys????
:::Oh yes, I almost forgot to tell you, I have lost the 42 voltage readings and we are now back to voltage being on the anodes of 6F6 and 6AD7 only......not sure if this is to our advantage or not.
:::Regards
::
::
::*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>
::
::What is that thing that looks like "link" off of the 5U4 filament? Wouldn't that thing being open lose you the screen Voltage to the output tubes???
::
::Lewis
:::
:::
:::
:::
::::Edd,
::::
::::I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
::::
::::Radiodoc
::::************
::::
::::
:::::::Edd,
:::::::
:::::::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
::::::
::::::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
::::::de Edd
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::73's de Edd
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::::
:::::::Radiodoc
:::::::************
:::::::
:::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
::::::::
::::::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
::::::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
::::::::
::::::::
::::::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
::::::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
::::::::
::::::::
::::::::
::::::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
::::::::
::::::::
::::::::Thassist
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::73's de Edd
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::
::::::::::Schema …J-pegged …so you may have to mag it on up in size….
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::
Your measurement of zero Ohms from the screen grids (G2) of the 6F6 and 6AD7 to ground is the problem. The screen grids of the two tubes are connected to the out lead of the choke and cap 68 thru wiring. That junction is where you measured zero ohms before. You will need to trace out that circuit starting at the choke out lead. That circuit branches out a few times. As Edd mentioned you may have to unsolder and isolate the different branches until you no longer measure zero ohms. When you find and remove the short you will have voltage on the screens again.
Radiodoc
************
:I have redone the previous measurements and it appears that we are back where we began.
:All filaments have voltages and the anodes of 6F6 and 6FD7 are reading 206 volts each.
:All voltages are being taken with negative probe of meter on the negative lead of capacitor 68 ( 30mfd )......readings are:
:
:The grids of 6F6 and 6FD7 to ground are zero ohms.
:
:Ground to in lead of speaker choke...190 volts
:Ground to out lead of speaker choke is...zero volts
:I unsoldered out lead connection to speaker choke......we now have 136 volts on the out lead.
:
:With lead to speaker choke unsoldered....anode of 6F6 is 64 volts and anode of 6AD7 is 165 volts..no voltage on screen grids.
:
:The readings for the resistors on that voltage divider did not change....same resistance.......Looks as if we’re back to square one.
:Let me know if you need more readings...however, I’ll continue to look for shorts.
:Regards
:
:
:
:
::Lewis,
::
::That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
::
::Radiodoc
::************
::
::
::::Sorry about the resistance check Doc. Anyhow I took a couple of readings of the outlead of the speaker choke to chassis but I’m still not sure where I should be going for chassis. Anyhow, from speaker outlead to negative junction of 40mfd and 100mfd caps...288 ohms.......speaker outlead to negative of Cap 68 (30mfd)......zero ohms.......speaker outlead to terminal point on metal chassis...zero ohms.
::::Since my last message I almost started the Third World War. I had disconnected some leads to connectors on the voltage divider to recheck resistance and I was foolish enough to put power on the radio.....the 100 mfd capacitor blew like a bomb. After the fallout had settled I replaced another new one. I am confused as to what is connected to the positive of this 100mfd electrolytic capacitor since it goes to ground but I noticed that the outlead of the speaker choke is connected to the positive lead. Do this seem right to you guys????
::::Oh yes, I almost forgot to tell you, I have lost the 42 voltage readings and we are now back to voltage being on the anodes of 6F6 and 6AD7 only......not sure if this is to our advantage or not.
::::Regards
:::
:::
:::*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>
:::
:::What is that thing that looks like "link" off of the 5U4 filament? Wouldn't that thing being open lose you the screen Voltage to the output tubes???
:::
:::Lewis
::::
::::
::::
::::
:::::Edd,
:::::
:::::I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
:::::
:::::Radiodoc
:::::************
:::::
:::::
::::::::Edd,
::::::::
::::::::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
:::::::
:::::::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
:::::::de Edd
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::73's de Edd
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::
::::::::
::::::::Radiodoc
::::::::************
::::::::
::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
:::::::::
:::::::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
:::::::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
:::::::::
:::::::::
:::::::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
:::::::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
:::::::::
:::::::::
:::::::::
:::::::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
:::::::::
:::::::::
:::::::::Thassist
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::73's de Edd
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::
:::::::::::Schema …J-pegged …so you may have to mag it on up in size….
:::::::::::
:::::::::::
:::::::::::
:::::::::::
:::::::::::
:::::::::
Gentlemen, I don’t know where to go from here......I have checked for shorts, removed wires replaced them and cannot do anything to improve the performance of this radio.
I still don’t understand how there can be resistance between the grids of 6F6 and 6AD7 to the negative of c68 (30mfd), since there is a direct wire connecting those two points.....my understanding of those circuits is limited and I just can’t understand how this can be.
Should I order resistors for the voltage divider? Can a complete unit be purchased incased in a metal strip as in the chassis at this time?? Can you recommend a supplier? Sorry for the questions.....I appreciate what you have been doing for me.
Regards
:Job,
:
:Your measurement of zero Ohms from the screen grids (G2) of the 6F6 and 6AD7 to ground is the problem. The screen grids of the two tubes are connected to the out lead of the choke and cap 68 thru wiring. That junction is where you measured zero ohms before. You will need to trace out that circuit starting at the choke out lead. That circuit branches out a few times. As Edd mentioned you may have to unsolder and isolate the different branches until you no longer measure zero ohms. When you find and remove the short you will have voltage on the screens again.
:
:Radiodoc
:************
:
:
::I have redone the previous measurements and it appears that we are back where we began.
::All filaments have voltages and the anodes of 6F6 and 6FD7 are reading 206 volts each.
::All voltages are being taken with negative probe of meter on the negative lead of capacitor 68 ( 30mfd )......readings are:
::
::The grids of 6F6 and 6FD7 to ground are zero ohms.
::
::Ground to in lead of speaker choke...190 volts
::Ground to out lead of speaker choke is...zero volts
::I unsoldered out lead connection to speaker choke......we now have 136 volts on the out lead.
::
::With lead to speaker choke unsoldered....anode of 6F6 is 64 volts and anode of 6AD7 is 165 volts..no voltage on screen grids.
::
::The readings for the resistors on that voltage divider did not change....same resistance.......Looks as if we’re back to square one.
::Let me know if you need more readings...however, I’ll continue to look for shorts.
::Regards
::
::
::
::
:::Lewis,
:::
:::That would but he measured voltage on the input lead of the choke. He has measured zero ohms on the out side of the choke. He will need to find where the short is in the lesser B+ circuit from the out lead of the choke.
:::
:::Radiodoc
:::************
:::
:::
:::::Sorry about the resistance check Doc. Anyhow I took a couple of readings of the outlead of the speaker choke to chassis but I’m still not sure where I should be going for chassis. Anyhow, from speaker outlead to negative junction of 40mfd and 100mfd caps...288 ohms.......speaker outlead to negative of Cap 68 (30mfd)......zero ohms.......speaker outlead to terminal point on metal chassis...zero ohms.
:::::Since my last message I almost started the Third World War. I had disconnected some leads to connectors on the voltage divider to recheck resistance and I was foolish enough to put power on the radio.....the 100 mfd capacitor blew like a bomb. After the fallout had settled I replaced another new one. I am confused as to what is connected to the positive of this 100mfd electrolytic capacitor since it goes to ground but I noticed that the outlead of the speaker choke is connected to the positive lead. Do this seem right to you guys????
:::::Oh yes, I almost forgot to tell you, I have lost the 42 voltage readings and we are now back to voltage being on the anodes of 6F6 and 6AD7 only......not sure if this is to our advantage or not.
:::::Regards
::::
::::
::::*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*<>*><*><*<>*><*<>*><*<>*><*<>
::::
::::What is that thing that looks like "link" off of the 5U4 filament? Wouldn't that thing being open lose you the screen Voltage to the output tubes???
::::
::::Lewis
:::::
:::::
:::::
:::::
::::::Edd,
::::::
::::::I am waiting for a resistance reading from the out lead of the choke and chassis. I am pretty sure there is a short there somewhere and the low B+ is being dropped across the choke. Job tried a jumper across the choke and this killed the B+ on the input of the choke. I still think there is a short or almost a short on the lower B+. Some of the wiring in the set is pretty bad. In the pic there is a blue wire in the upper portion that has most of its insulation gone. There are probably others too. I am betting on a wire shorting to chassis on the lower B+ circuit somewhere.
::::::
::::::Radiodoc
::::::************
::::::
::::::
:::::::::Edd,
:::::::::
:::::::::From the looks of Job's picture the canned resistor has been replaced sometime or the other as it is held down with screw(s) instead of rivits and it seems to contain 5 resistors instead of 4 noted on the schematic.
::::::::
::::::::Agreed...and it looks like the unit is not even well mounted...slightly spaced off.... as to have intimate connection with the chassis for optimal heat sinking, as well as the floater power resistor tacked in between two terminals. Wonder if a person in the past just thought that it looked the same mechanically, so lets see if it will work....even with the extra terminal..no less !
::::::::de Edd
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::73's de Edd
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::
:::::::::
:::::::::Radiodoc
:::::::::************
:::::::::
:::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::What you are showing us is a Muter corps power strap resistor with all of those resistor sections of the voltage divider, contained internally as separate nichrome windings on a core, I pointed it out earlier on the center area of the provided schematic, but assume the cluster to be separate individual resistor units. The center of that resistor seems to have its ground connection right at the point just above the chassis edge where you seem to have a red wire resting under it.
::::::::::
::::::::::The other two sections of the resistor seem to be to the left of that ground point WITH one section being bad in the past….ergo the reason for that add on reddish colored power resistor that has been soldered between two terminals. It has been HOT for sometime, as you can see by its center discoloration area.
::::::::::So what you need to do is pull out ye olde trusty ohmmeter and enact a resistance check across each section of that resistor, you have one section that is way off in value, of the 22 and 135 ohm units in the series, thus the reason for that 42 volt reading that you are getting .
::::::::::
::::::::::
::::::::::Now in referring to the separate B+ divider aspect that gets connected to the far right end resistor section, that line to the output of the section with R33 and R42 sections. Let’s take our metering now and go to either the + of C 68 cap / or the output terminal of the speaker field coil ( the same) and read the resistance with the other ohmmeter at the right terminal of R42 and expect VEWY close to Zero ohms. Your readings suggest that wiring circuit connection is open, between those points.
::::::::::The negative lead of C68 is a good place to keep your metering ground lead for future voltage readings, if you confirm it also being 0 ohms to ground.
::::::::::
::::::::::
::::::::::
::::::::::Now go check out those resistor values and the missing sub B+ at the R42 right terminal.
::::::::::
::::::::::
::::::::::Thassist
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::73's de Edd
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::
::::::::::::Schema …J-pegged …so you may have to mag it on up in size….
::::::::::::
::::::::::::
::::::::::::
::::::::::::
::::::::::::
::::::::::
You sure have been having fun with this set! What part of the country are you in? Perhaps someone in your vicinity would be willing to take a look at your set...sometimes a look-see from an experienced repair person will find the problem a lot faster than via a forum or emails. I'm in south Texas and I'm willing to look at your set if you live in the area.
:You sure have been having fun with this set! What part of the country are you in? Perhaps someone in your vicinity would be willing to take a look at your set...sometimes a look-see from an experienced repair person will find the problem a lot faster than via a forum or emails. I'm in south Texas and I'm willing to look at your set if you live in the area.
Drop by D-FW enroute….and BTW…you will find your boarding pass to be en route to Newfoundland / Nova Scotia
73's de Edd
However, the advice and encouragement from the contributors to this forum is priceless and I have been helped tremendously. It’s too bad that some sort of official recognition could not be given to the half a dozen or so who guide the rest of us in our labour of love. Naturally the person hosting this site deserves a bouquet as well.
Now as for an update….nothing to report really. Edd and Doc have been plugging along with me as you can all see and hopefully soon I’ll have that darn short found.
Time for bed….Good night everyone.
::Job,
::You sure have been having fun with this set! What part of the country are you in? Perhaps someone in your vicinity would be willing to take a look at your set...sometimes a look-see from an experienced repair person will find the problem a lot faster than via a forum or emails. I'm in south Texas and I'm willing to look at your set if you live in the area.
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:Drop by D-FW enroute….and BTW…you will find your boarding pass to be en route to Newfoundland / Nova Scotia
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:73's de Edd
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I just inserted this down at the currently bottom most portion of the thread...
OH TAY...let's just see if we can end all of this....'rat now.
I am starting with an amending in of the additional circuitry that I did not have incorporated within the central area of the original, incomplete schematic. Only points of interest, along the sub B+ line have been placed in, no isolated lines that end up running off into high value resistance have been included, and the new schema has been placed at the bottom of the page.
In a compiling all of the info that you have fed forth...particularly of the last resistive values of the Muter power strip resistor, this is what we come up with.
We see the initial derivation of the RAW B+ at the filament of the rectifier tube and its distribution to the input filter thru the link and then going down to C82 for its initial DC filtering and then being fed on up to the AF output transformer to feed each of the plates of the AF output tubes. This is all shown by the broken red lines and all of that supply line seems to be in order and seems to be of no further concern.
Now, here is the loop where the trouble needs to tracked out.
The raw B+ then flows thru your field winding of the speaker to get a bit more inductive filtering and then its feed down into C68 for its additional filtering action, normally that produced sub level of B+ would then be sent upward from the point I have assigned the blue[A] designation.
The idea now is to track the sub B + load line on up the alphabet trail, to its very end.....possibly at [G]….however, with use of your feed back....I don't think that we will even make it past test point[B] .
The idea now is to clip connect your ohmmeter leads across electrolytic C68 so that you will be constantly monitoring the "short" present across the sub B+ distribution line. That would be tied into node [A] and the (3) would be indicative of 3 connections at that point,
1... being the output of the field coil which you have had disconnected and found no fault with .
2... the second leg going down to the C68 capacitor which you have found fault free.
3... the last route is upward via a wire to the point where there is connection [B] to the outer terminal of the MUTER's R42 resistor section.
That will be node [B] with its 3 connections...which are: Awaiting your test results....
1...the outer terminal of R42 resistor
2... the wire that you were just tracking down to this point
3... a third wire that travels upward to feed both screen grids of the AF output tubes and then there is a branch off to feed B+ to the 2nd IF tube plate transformer and a like transformer down in the amplified AVC circiutry.
In blowing up your photo of the greater under chassis and examining the the MUTER's third terminal from the left, it certainly appears that the very base of that terminal is fused to the ground(ed) strap housing that that is peripherally crimped around (radially) the internally insulated resistive elements core. Which would be correct.
Some how or fashion, that extreme right R42 section terminal is also being grounded.
Confirm the above by your ohmmeters response when you lift both of those wires off from that terminal, yet there will still be the maintaining of a connection between the two wires themselves.
If the short is still there, then we move on up to [C]...but some how.... I think that we stop here.
73's de Edd
Edd does a great job with his highlighted schematics. Sounds like Edd is zooming in on the problem but in the meantime I need to go back and digest all the info presented so far. Nuthin' like cracking a tough nut like this one.
With the output line of the speaker choke disconnected from the end of R42, and the line from the screen grids of 6F6 and 6AD7 disconnected and both connected together....22m ohms and rising on my meter.
With the grid line disconnected and the out choke line reconnected .....21k ohms
With screen grid line connected and output choke line disconnected....0 ohms
I disconnected the screen grid line going to 6FA7.....0 ohms....all other lines were connected
I disconnected the screen grid line to 6F6....2m ohms and rising...all other lines had been connected
Now I’m really curious.
Regards
PS: Rene, thanks for your comments and it is my intent to order resistors
:After reading and digesting all these threads, I think Edd et al nailed it earlier...completely replace that PITA multisection candohm resistor and start off with known good components. Nowadays when I come across them, I automatically replace them with appropriate individual resistors. Get yourself a terminal strip and mount it where the existing candohm is, then mount your 4 appropriate resistors in series, then connect the wiring at the appropriate points. If the parts list doesn't spell out the wattage (and candohm section wattages aren't often specified) then the wattage will have to be calculated (not a big deal). Using ohms law, the current through the grid bias resistors should be I=E/R or 22 volts/(135+22) or .14 amps. Wattages will then be .14 amps squared * 135 (2.6 watts but go with 5) and .14 amps squared * 22 (.43 watts but go with 1). The B+ voltage divider wattages are easy to calculate because the voltages are specified (275-->400-->gnd). My schematic copy is not the greatest so I may have some incorrect values.
Ahhhh Soooo !....lookee likee you be gettee velly close now ! :
I disconnected the screen grid line to 6F6....2m ohms and rising...all other lines had been connected
Check out that 6F6 screen supply wire at both of its ends for finding the end going into a short and stay with the end that has the short on it. But, supposedly now, the end that is connected at the 6F6 proper and then stay monitoring the low ohmmage and (unplug the 6F6)…(fat chance)…. And then check to confirm that the wire is indeed going to pin # 4 , the valid screen grid connection of the 6F6. Next you would check for exposed insulation along that wire length or a pinch condition to ground. Also a solder splash about the tube , or a miswire that might been connected to the 6F6 in the past by another person.
ZUJ’ing….
73's de Edd
s.
Gees, Is it ever possible that this could be??
Regards
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:Ahhhh Soooo !....lookee likee you be gettee velly close now ! :
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: I disconnected the screen grid line to 6F6....2m ohms and rising...all other lines had been connected
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: Check out that 6F6 screen supply wire at both of its ends for finding the end going into a short and stay with the end that has the short on it. But, supposedly now, the end that is connected at the 6F6 proper and then stay monitoring the low ohmmage and (unplug the 6F6)…(fat chance)…. And then check to confirm that the wire is indeed going to pin # 4 , the valid screen grid connection of the 6F6. Next you would check for exposed insulation along that wire length or a pinch condition to ground. Also a solder splash about the tube , or a miswire that might been connected to the 6F6 in the past by another person.
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:ZUJ’ing….
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:73's de Edd
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:s.
Amazing…indeed a rare..rare case....typically wouldn’t have expected it, but pull out ye olde 6F6 toobie and do an ohms test between its pin #4 (G2)
and its pin #8 (cathode) and that should confirm…. if the same short value shows up
between them.
73's de Edd
Sorry for being late getting back.....I checked the resistance from pin 4 to pin 8 of the 6F6 tube and not surprisingly got continuity. How did that little wire from the screen grid end up in contact with the cathode?? Interesting......However, for me this has been an educational exercise and to think I considered quitting a couple of times....I’m not assuming my problems are over with this one yet but one step at a time, and now I’ll look for a sub for 6F6....I’m sure I have a 6K6 around somewhere.....I’ll be getting back to you all.
Thanks gentlemen for walking me through this troubleshooting exercise......I won’t even pretend I could have done it by myself.
Regards
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:Amazing…indeed a rare..rare case....typically wouldn’t have expected it, but pull out ye olde 6F6 toobie and do an ohms test between its pin #4 (G2)
:and its pin #8 (cathode) and that should confirm…. if the same short value shows up
:between them.
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:73's de Edd
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Get another tube in there and let's see if the set works! It might even work without the 6F6, being a push-pull output and all.
:I doubt the short is between the screen grid and the cathode, but rather the screen grid and the suppressor grid. However the suppressor grid is tied to the cathode internally. That is why Edd had you check the resistance between pins 4 and 8.
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:Get another tube in there and let's see if the set works! It might even work without the 6F6, being a push-pull output and all.
*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Well, check out R25, that otter getcha music playing. This one was fun...just shows to go that "When I teach, I learn"
Lewis
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::I doubt the short is between the screen grid and the cathode, but rather the screen grid and the suppressor grid. However the suppressor grid is tied to the cathode internally. That is why Edd had you check the resistance between pins 4 and 8.
::
::Get another tube in there and let's see if the set works! It might even work without the 6F6, being a push-pull output and all.
If you don't have sub B+ reduced and fed all of the way down to the plate of the 6R7, remember that you were shedding loads in the troubleshooting , so be sure that the line to the right from the point where I have the RED X is not at fault , with some wiring left loose.
If all of that checks out, then the sub B+ supply loop up to that point is OK and then look over to the left of the RED X .
Additionally you were probably involved with the replacement of the C61 electrolytic , so be sure that all is well at that area, as it is near that same supply node for the feed down to the 6 Ruhh 7.
To finally confirm the circuitry,check out voltage points from [A] thru [D].
>
73's de Edd
A...zero
B...225v
C...27v
D...5 v
I also disconnected resistor R25 from the anode of 6R7 and measured voltage at end of resistor...167v
Regards
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:If you don't have sub B+ reduced and fed all of the way down to the plate of the 6R7, remember that you were shedding loads in the troubleshooting , so be sure that the line to the right from the point where I have the RED X is not at fault , with some wiring left loose.
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: If all of that checks out, then the sub B+ supply loop up to that point is OK and then look over to the left of the RED X .
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:Additionally you were probably involved with the replacement of the C61 electrolytic , so be sure that all is well at that area, as it is near that same supply node for the feed down to the 6 Ruhh 7.
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:To finally confirm the circuitry,check out voltage points from [A] thru [D].
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:73's de Edd
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:A...zero
:B...225v
:C...27v
:D...5 v
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:I also disconnected resistor R25 from the anode of 6R7 and measured voltage at end of resistor...167v
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:Regards
Zero volts at "A" doesn't make any sense at all considering you have 225 volts at "B" unless the B+ wiring is hacked up and B+ voltage is getting there via another path (if this were my radio I'd grab a highlighter and compare actual wiring with the schematic). The voltages at "C" and "D" appear to be way too low and may be dragged down by leaky C61, C62, and possibly C64. Have you replaced any of the paper caps yet?
::A...zero
::B...225v
::C...27v
::D...5 v
::
::I also disconnected resistor R25 from the anode of 6R7 and measured voltage at end of resistor...167v
::
::Regards
:
:Zero volts at "A" doesn't make any sense at all considering you have 225 volts at "B" unless the B+ wiring is hacked up and B+ voltage is getting there via another path (if this were my radio I'd grab a highlighter and compare actual wiring with the schematic). The voltages at "C" and "D" appear to be way too low and may be dragged down by leaky C61, C62, and possibly C64. Have you replaced any of the paper caps yet?
Rene is definately agreed with on that!!! R25 and friends are my favorite suspects.
Lewis
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:A...zero
:B...225v
:C...27v
:D...5 v
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:I also disconnected resistor R25 from the anode of 6R7 and measured voltage at end of resistor...167v
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The real kicker was your lifting the plate connection of the 6R7 and the voltage shifting all of the way up to 167, which would be a very,very minimal sloughing off of the voltage at that node by the mentioned capacitors being only ever so slightly leaky, and the way that they are somewhat high resistor value isolated.
Instead, suspect the 1st grid biasing on that 6R7 tube to be at odds from the norm.
For confirmation, place the removed connection back to its plate and then ground the 1st grid if the 6R7 tube to ground and expect the voltage monitored at its plate to shoot up again, somewhat like it was when the resistor was disconnected.
If confirmed so, the most likely suspect would be the C60 coupling capacitor that is from the plate of the 6SK7 1st audio amp to the 1st grid of the mentioned 6R7.
(On the Ref schematic…. it is the second part to the left of the point where I have yellow marked up the C61 electrolytic capacitor.)
For a quickie testing, merely do the grounding of the left referenced lead of that cap to ground and then confirm that the 6R7 plate voltage does not then come on up towards the norm.
If so …..one .01 ufd cap….. please at an ~ 400-600 VDC rating.
A final consideration …very minor…is the fact that the -2.5 supply also gradually routes into the 6R7 1st grid circuitry, but at one time looong ago, I believe that you said that those voltages were being developed, but possibly in the wrong ratios due to the ~ 2X resistive scaling error in their resistive dividers values.
Schema ref:
73's de Edd
I disconnected end of C60 and got a reading of 61 volts on plate of tube 6R7. Checked capacitance of C60 and reading was .04 mfd. I replaced it with a .015 mfd and now I have 60 volts on plate of 6R7 and I believe that’s what it is supposed to be.
Wheww....it sure has been interesting and educational but this sweetie is still not talking to me. I am receiving a gentle hum and I’m sure she is anxious to talk....I will get at her later but if you have any suggestions, pass them along.
Thanks everyone for your tremendous assistance.
Job
::O.K, let’s see what we have.....I checked in detail once more for shorts, loose wire ends, etc....all appeared to be fine. Edd the readings you asked for are as follows:
::A...zero
::B...225v
::C...27v
::D...5 v
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::I also disconnected resistor R25 from the anode of 6R7 and measured voltage at end of resistor...167v
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:The real kicker was your lifting the plate connection of the 6R7 and the voltage shifting all of the way up to 167, which would be a very,very minimal sloughing off of the voltage at that node by the mentioned capacitors being only ever so slightly leaky, and the way that they are somewhat high resistor value isolated.
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:Instead, suspect the 1st grid biasing on that 6R7 tube to be at odds from the norm.
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:For confirmation, place the removed connection back to its plate and then ground the 1st grid if the 6R7 tube to ground and expect the voltage monitored at its plate to shoot up again, somewhat like it was when the resistor was disconnected.
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:If confirmed so, the most likely suspect would be the C60 coupling capacitor that is from the plate of the 6SK7 1st audio amp to the 1st grid of the mentioned 6R7.
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:(On the Ref schematic…. it is the second part to the left of the point where I have yellow marked up the C61 electrolytic capacitor.)
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:For a quickie testing, merely do the grounding of the left referenced lead of that cap to ground and then confirm that the 6R7 plate voltage does not then come on up towards the norm.
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:If so …..one .01 ufd cap….. please at an ~ 400-600 VDC rating.
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:A final consideration …very minor…is the fact that the -2.5 supply also gradually routes into the 6R7 1st grid circuitry, but at one time looong ago, I believe that you said that those voltages were being developed, but possibly in the wrong ratios due to the ~ 2X resistive scaling error in their resistive dividers values.
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:Schema ref:
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:73's de Edd
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If you don't have a signal generator, a soldering iron touched at the points above should induce a 60 Hz sound at the speaker. Some recommend using a finger but I never do that...you never know what problems lurk inside these radios! If you get sound at the speaker with the two tests above, then we'll have to move further "upstream".
J
:Do you have a signal generator by any chance? If so, put it in AF (audio frequency) mode and inject a signal at the control grid (G) of the 1st AF amp. Depending on the injected signal strength, you should get a nice 400 Hz signal at the speaker. If you get this signal, then move to the 6R7 detector/AF amp and inject the signal at the grid cap.
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:If you don't have a signal generator, a soldering iron touched at the points above should induce a 60 Hz sound at the speaker. Some recommend using a finger but I never do that...you never know what problems lurk inside these radios! If you get sound at the speaker with the two tests above, then we'll have to move further "upstream".
:Yes, a signal at both of those grids using a soldering iron.
:J
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::Do you have a signal generator by any chance? If so, put it in AF (audio frequency) mode and inject a signal at the control grid (G) of the 1st AF amp. Depending on the injected signal strength, you should get a nice 400 Hz signal at the speaker. If you get this signal, then move to the 6R7 detector/AF amp and inject the signal at the grid cap.
::
::If you don't have a signal generator, a soldering iron touched at the points above should induce a 60 Hz sound at the speaker. Some recommend using a finger but I never do that...you never know what problems lurk inside these radios! If you get sound at the speaker with the two tests above, then we'll have to move further "upstream".
5U4 (Rect)..pin 1(f+) = 316v; pin 8(f-) = 316v; 6F6 (Output)..pin 3(a) = 309v; pin 4(g2) =291v; 6AD7 (Output )..pin 3(a) =308v; pin 4(g2)=291v; 6SK7 (1st AF ).. Pin 6(g2)= 53v; pin 8 (a) = 160v; 6R7 (2nd Det ).. Pin 3 (a) = 59v; 6SK7 (2nd I.F ).. Pin 6 (g2) =94v; pin 8 (a) =286v; 6SK7 (1st I.F ).. Pin 6 (g2)=95v; pin 8 (a)=291v; 6B8 ( AVC amp )..pin 3 (a)=291v; pin 6 (g2)= 114v; 6SA7 (1st Det ).. Pin 3 (a ) =95v; pin 4 ( g2+g4 ) = 96v; 6SA7 ( Osc. )..pin 3 ( a ) = 266v; pin 4 ( g2+g4) =96v; 6SK7 ( RF amp ).. Pin 6 (g2) =96v; pin 8 (a) =261v
:It appears the audio section is working then. A signal generator set at IF frequency would come in real handy right now. Lacking that, check the voltages on the IF amplifier and converter tubes.
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::Yes, a signal at both of those grids using a soldering iron.
::J
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:::Do you have a signal generator by any chance? If so, put it in AF (audio frequency) mode and inject a signal at the control grid (G) of the 1st AF amp. Depending on the injected signal strength, you should get a nice 400 Hz signal at the speaker. If you get this signal, then move to the 6R7 detector/AF amp and inject the signal at the grid cap.
:::
:::If you don't have a signal generator, a soldering iron touched at the points above should induce a 60 Hz sound at the speaker. Some recommend using a finger but I never do that...you never know what problems lurk inside these radios! If you get sound at the speaker with the two tests above, then we'll have to move further "upstream".
I'm not seeing any problems with those voltages. A signal generator right now would be nice...what are the odds of you getting your hands on one? With a signal gen, you would inject a modulated 455 kc signal into the grid of the 2nd IF to see if the 400 hz audio signal can be heard. If so, then you would move to the 1st IF and repeat. If not, the trouble would like either in the 2nd IF stage or the detector stage (open coils, etc).
In the absence of a signal gen, are you getting anything at all at the speaker? With the volume at max? Try rotating the band selector repeatedly...if nothing, hit the contacts with deoxit or WD-40. Touch the grid cap of the 1st detector...anything?
:Good Day......I have some voltage readings which you requested Rene.....I think they’re o.k..
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:5U4 (Rect)..pin 1(f+) = 316v; pin 8(f-) = 316v; 6F6 (Output)..pin 3(a) = 309v; pin 4(g2) =291v; 6AD7 (Output )..pin 3(a) =308v; pin 4(g2)=291v; 6SK7 (1st AF ).. Pin 6(g2)= 53v; pin 8 (a) = 160v; 6R7 (2nd Det ).. Pin 3 (a) = 59v; 6SK7 (2nd I.F ).. Pin 6 (g2) =94v; pin 8 (a) =286v; 6SK7 (1st I.F ).. Pin 6 (g2)=95v; pin 8 (a)=291v; 6B8 ( AVC amp )..pin 3 (a)=291v; pin 6 (g2)= 114v; 6SA7 (1st Det ).. Pin 3 (a ) =95v; pin 4 ( g2+g4 ) = 96v; 6SA7 ( Osc. )..pin 3 ( a ) = 266v; pin 4 ( g2+g4) =96v; 6SK7 ( RF amp ).. Pin 6 (g2) =96v; pin 8 (a) =261v
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::It appears the audio section is working then. A signal generator set at IF frequency would come in real handy right now. Lacking that, check the voltages on the IF amplifier and converter tubes.
::
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:::Yes, a signal at both of those grids using a soldering iron.
:::J
:::
::::Do you have a signal generator by any chance? If so, put it in AF (audio frequency) mode and inject a signal at the control grid (G) of the 1st AF amp. Depending on the injected signal strength, you should get a nice 400 Hz signal at the speaker. If you get this signal, then move to the 6R7 detector/AF amp and inject the signal at the grid cap.
::::
::::If you don't have a signal generator, a soldering iron touched at the points above should induce a 60 Hz sound at the speaker. Some recommend using a finger but I never do that...you never know what problems lurk inside these radios! If you get sound at the speaker with the two tests above, then we'll have to move further "upstream".
O.K. sounds like you need to need to an RF analysis, with most of your voltages now being in the ball park with no grossly
variant values, such as was initially present at the plate supply level of the 6Ruh6
I heard no comeback on the RF generator aspect yet, so considering the probability of you having a pulled chassis available
that is working on the AM band, it could then be utilized for a troubleshooting being worked out with use of that donor sets signal.
Hopefully it’s an AC powered set also, so that there would be no inter chassis voltage differentials being present in a chassis
to chassis connect up.
Or, that could be dodged with a use of an AC isolation transformer feeding the new donor chassis, or lastly the initial metering of
chassis to chassis AC voltages, and swapping the AC power plug polarity on one and then the use of the lower voltage combination.
Then the keeping of the metering between chassis' and then the 3 second additional connecting of a 1k resistor between chassis to
confirm if the voltage plummets to almost zero...or a low value...thus signifying the existent voltage merely being a static rather
than a dynamic voltage level.
That confirmed, and then you should be able to safely connect both chassis pans together with a clip lead.
The next portion of the procedure would be to enact a test that should produce a talking set on a portion that RF signal is fed thru.
You would then be taking the new test receiver and tuning it into your strongest received AM signal and then the consulting of its schematic
to locate the plate pin connection of the IF amplifier tube. That will then be the sourcing of the very highest level of 455khz I.F. signal being produced within your test receiver.
Now you place those receivers close enough together so that you can get a test lead(s) and its end clips between the pin #4...1st grid of your Q44's I.F. amplifier tube.... and the other point of interest was the afore mentioned plate pin of the IF tube of the donor receiver.
What you will be doing is enacting a minor degree of coupling of the strong 455 IF signal present at the donor receiver into the IF amp stage of your Q44 receiver.
You initially clip one test lead onto the plastic / cotton wire of the donor receivers IF plate and the other end of the test leads test clip goes to the plastic / cotton wire of the 1st grid of the Q44 receiver. Note that I am saying to the INSULATED portion of the wire not a metallic contact action being made. We merely want the finitely small degree of stray capacitive coupling that will be produced in that manner.
Have the Q44 set to AM and your ears perked up for potentially your first peep out of that unit for the last 23 years,23 weeks,23 days,23 hours and 23 minutes.
Hopefully the degree of inter coupling was enough, to have punched a 455khz signal thru a mere freq differential of going into a 460khz strip.
If no luck then, enhance the capacitive coupling with a 1 inch squares of alumun-i-ninny-yum foil round wrapped about each wire and then clip onto the center of the wraps to connect. That should up the derived capacitive coupling.
Still no go ?... then take the test clip at the donor receivers plate and connect it directly to that tubes plate pin connection, letting the Q44 end still be receiving its coupling thru the "psuedo"capacitor .
Should that donor sets station have passed thru the Q44 and lets its programming be heard, then move the connect between the plate of the donor receiver and the grid (#8) of the 6SA7 tube, you my still have to step through the different degrees of signal coupling to reach the level that a signal has then made it all of the way thru the mixer, thru the IF and finally the audio circuitry.
Wheee.
That only leaves the mixer proper section to troubleshoot, with a possibly its local oscillator is not working..
Standing by for feedback.....
73's de Edd
Hopefully I’ll have that signal generator tomorrow and we’ll see how I do with it.
Regards
PS: This thread is getting really strung out...should I begin a new one or continue with this one?
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:O.K. sounds like you need to need to an RF analysis, with most of your voltages now being in the ball park with no grossly
:variant values, such as was initially present at the plate supply level of the 6Ruh6
:
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:
:I heard no comeback on the RF generator aspect yet, so considering the probability of you having a pulled chassis available
:that is working on the AM band, it could then be utilized for a troubleshooting being worked out with use of that donor sets signal.
:
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:
:Hopefully it’s an AC powered set also, so that there would be no inter chassis voltage differentials being present in a chassis
: to chassis connect up.
:
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:Or, that could be dodged with a use of an AC isolation transformer feeding the new donor chassis, or lastly the initial metering of
:chassis to chassis AC voltages, and swapping the AC power plug polarity on one and then the use of the lower voltage combination.
:Then the keeping of the metering between chassis' and then the 3 second additional connecting of a 1k resistor between chassis to
:confirm if the voltage plummets to almost zero...or a low value...thus signifying the existent voltage merely being a static rather
:than a dynamic voltage level.
:That confirmed, and then you should be able to safely connect both chassis pans together with a clip lead.
:
:
:
:The next portion of the procedure would be to enact a test that should produce a talking set on a portion that RF signal is fed thru.
:
:
:
:You would then be taking the new test receiver and tuning it into your strongest received AM signal and then the consulting of its schematic
: to locate the plate pin connection of the IF amplifier tube. That will then be the sourcing of the very highest level of 455khz I.F. signal being produced within your test receiver.
:
:
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:Now you place those receivers close enough together so that you can get a test lead(s) and its end clips between the pin #4...1st grid of your Q44's I.F. amplifier tube.... and the other point of interest was the afore mentioned plate pin of the IF tube of the donor receiver.
:
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:What you will be doing is enacting a minor degree of coupling of the strong 455 IF signal present at the donor receiver into the IF amp stage of your Q44 receiver.
:
:
:You initially clip one test lead onto the plastic / cotton wire of the donor receivers IF plate and the other end of the test leads test clip goes to the plastic / cotton wire of the 1st grid of the Q44 receiver. Note that I am saying to the INSULATED portion of the wire not a metallic contact action being made. We merely want the finitely small degree of stray capacitive coupling that will be produced in that manner.
:
:Have the Q44 set to AM and your ears perked up for potentially your first peep out of that unit for the last 23 years,23 weeks,23 days,23 hours and 23 minutes.
:
:Hopefully the degree of inter coupling was enough, to have punched a 455khz signal thru a mere freq differential of going into a 460khz strip.
:
:If no luck then, enhance the capacitive coupling with a 1 inch squares of alumun-i-ninny-yum foil round wrapped about each wire and then clip onto the center of the wraps to connect. That should up the derived capacitive coupling.
:
:
:Still no go ?... then take the test clip at the donor receivers plate and connect it directly to that tubes plate pin connection, letting the Q44 end still be receiving its coupling thru the "psuedo"capacitor .
:
:Should that donor sets station have passed thru the Q44 and lets its programming be heard, then move the connect between the plate of the donor receiver and the grid (#8) of the 6SA7 tube, you my still have to step through the different degrees of signal coupling to reach the level that a signal has then made it all of the way thru the mixer, thru the IF and finally the audio circuitry.
:
:Wheee.
:
:That only leaves the mixer proper section to troubleshoot, with a possibly its local oscillator is not working..
:
:
:Standing by for feedback.....
:
:
:
:73's de Edd
:
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:
-----With cable plugged into the “AF” out-jack of the generator and touching grid of output tube 6AD7.....buzz
-----touching grid of output tube 6F6…no sound
----- touching grid of 1st AF tube 6SK7 ….buzz
----- touching grid of 2nd AF tube 6R7….buzz
-----With cable plugged into the “RF” out-jack of the generator and touching 2nd IF tube 6SK7….no sound..
Also no sound from other tubes
I’m curious as to why no audio from the 6F6 tube….C62 has been replaced so that’s not the problem.
Job
:Rene, I think I can get my hands on a signal generator...should know tomorrow......Edd, I connected another AC radio (chassis ) up to the Q44 as per instructions and did not have much success except to confirm that a signal is coming through the audio tubes.....no signal coming through the I.F or any other tubes. However, I was receiving feedback through the “second” radio when touching the grids of the various grids of the Q44 radio.
:Hopefully I’ll have that signal generator tomorrow and we’ll see how I do with it.
:Regards
:PS: This thread is getting really strung out...should I begin a new one or continue with this one?
:
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::O.K. sounds like you need to need to an RF analysis, with most of your voltages now being in the ball park with no grossly
::variant values, such as was initially present at the plate supply level of the 6Ruh6
::
::
::
::I heard no comeback on the RF generator aspect yet, so considering the probability of you having a pulled chassis available
::that is working on the AM band, it could then be utilized for a troubleshooting being worked out with use of that donor sets signal.
::
::
::
::Hopefully it’s an AC powered set also, so that there would be no inter chassis voltage differentials being present in a chassis
:: to chassis connect up.
::
::
::
::Or, that could be dodged with a use of an AC isolation transformer feeding the new donor chassis, or lastly the initial metering of
::chassis to chassis AC voltages, and swapping the AC power plug polarity on one and then the use of the lower voltage combination.
::Then the keeping of the metering between chassis' and then the 3 second additional connecting of a 1k resistor between chassis to
::confirm if the voltage plummets to almost zero...or a low value...thus signifying the existent voltage merely being a static rather
::than a dynamic voltage level.
::That confirmed, and then you should be able to safely connect both chassis pans together with a clip lead.
::
::
::
::The next portion of the procedure would be to enact a test that should produce a talking set on a portion that RF signal is fed thru.
::
::
::
::You would then be taking the new test receiver and tuning it into your strongest received AM signal and then the consulting of its schematic
:: to locate the plate pin connection of the IF amplifier tube. That will then be the sourcing of the very highest level of 455khz I.F. signal being produced within your test receiver.
::
::
::
::Now you place those receivers close enough together so that you can get a test lead(s) and its end clips between the pin #4...1st grid of your Q44's I.F. amplifier tube.... and the other point of interest was the afore mentioned plate pin of the IF tube of the donor receiver.
::
::
::What you will be doing is enacting a minor degree of coupling of the strong 455 IF signal present at the donor receiver into the IF amp stage of your Q44 receiver.
::
::
::You initially clip one test lead onto the plastic / cotton wire of the donor receivers IF plate and the other end of the test leads test clip goes to the plastic / cotton wire of the 1st grid of the Q44 receiver. Note that I am saying to the INSULATED portion of the wire not a metallic contact action being made. We merely want the finitely small degree of stray capacitive coupling that will be produced in that manner.
::
::Have the Q44 set to AM and your ears perked up for potentially your first peep out of that unit for the last 23 years,23 weeks,23 days,23 hours and 23 minutes.
::
::Hopefully the degree of inter coupling was enough, to have punched a 455khz signal thru a mere freq differential of going into a 460khz strip.
::
::If no luck then, enhance the capacitive coupling with a 1 inch squares of alumun-i-ninny-yum foil round wrapped about each wire and then clip onto the center of the wraps to connect. That should up the derived capacitive coupling.
::
::
::Still no go ?... then take the test clip at the donor receivers plate and connect it directly to that tubes plate pin connection, letting the Q44 end still be receiving its coupling thru the "psuedo"capacitor .
::
::Should that donor sets station have passed thru the Q44 and lets its programming be heard, then move the connect between the plate of the donor receiver and the grid (#8) of the 6SA7 tube, you my still have to step through the different degrees of signal coupling to reach the level that a signal has then made it all of the way thru the mixer, thru the IF and finally the audio circuitry.
::
::Wheee.
::
::That only leaves the mixer proper section to troubleshoot, with a possibly its local oscillator is not working..
::
::
::Standing by for feedback.....
::
::
::
::73's de Edd
::
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::
Setting the sig gen on AF...good. Hopefully you: 1. set the AF output level something above zero and 2. attached the ground wire of the cable to the chassis. One way to tell if the sig gen is working is to vary the AF output at the sig gen...the volume should go up and down.
I have to figure out what you're hearing when you say buzz...is it a ~400 hz tone or the same sound you got when you touched the grids with a soldering iron?
Let's assume you heard the sig gen's 400 Hz audio tone. There's still something wrong with the 6F6. You're hearing something at the speaker because the other half of the push-pull output is apparently working. We'll have to go back to the 6F6 a little later.
On to the RF setting of the sig gen. You were injecting a signal into the IF section so hopefully you: 1. had the sig gen controls set to internal modulation and 2. had the frequency set to the IF frequency of the set (I think it's 455 khz) and 3. had enough output from the sig gen. Crank it to max if you have to (signal gen and set volume). If you're not getting anything at the speaker, the last IF transformer may be seriously out of alignmen or there is a problem between the 2nd IF and the second detector.
Digest that info and get back.
:Okkkkkkkk......I have a signal generator now...Heathkit SG-8...and downloaded a manual from the internet to show its operation. I’m not sure just how accurate my testing is but this is the results:
:
:-----With cable plugged into the “AF” out-jack of the generator and touching grid of output tube 6AD7.....buzz
:-----touching grid of output tube 6F6…no sound
:----- touching grid of 1st AF tube 6SK7 ….buzz
:----- touching grid of 2nd AF tube 6R7….buzz
:
:-----With cable plugged into the “RF” out-jack of the generator and touching 2nd IF tube 6SK7….no sound..
:Also no sound from other tubes
:
:I’m curious as to why no audio from the 6F6 tube….C62 has been replaced so that’s not the problem.
:Job
:
:
:
Sort of sounds like you might still be fixated on AF injection, that seems to be OK as confirmed earlier.
Consult the markup of the face of yo’ gennie-rator faceplate for the settings on it .
Later, if you get stuck up, then consult your units’ manual printout on pages 17 forward….
INITIALLY
use that working “donor” receiver to fully familiarize your self with the “cause and effects” connotations,
of the manner of hook ups and adjustments made between the RF generator and the receiver being worked on.
You can probably even use the lightly coupled effect produced by clipping onto the insulated wire insulation of grid circuitry that I mentioned, on that working receiver, but use brute force coupling when you get to the Q44 , since it apparently / definitely has an RF passage problem if my aforementioned inter-coupling procedure between two receivers did not work for you.
Then you can , shift generator output freq to 460 khz IF freq output and graduate on and upwards to the Q44 set, initially starting at its IF grid stage, and then moving forward to the mixer section to confirm progressive RF passage from the very front end of the receiver.
73's de Edd
:Gees, Is it ever possible that this could be??
:Regards
:
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::
::Ahhhh Soooo !....lookee likee you be gettee velly close now ! :
::
::
:: I disconnected the screen grid line to 6F6....2m ohms and rising...all other lines had been connected
::
::
:: Check out that 6F6 screen supply wire at both of its ends for finding the end going into a short and stay with the end that has the short on it. But, supposedly now, the end that is connected at the 6F6 proper and then stay monitoring the low ohmmage and (unplug the 6F6)…(fat chance)…. And then check to confirm that the wire is indeed going to pin # 4 , the valid screen grid connection of the 6F6. Next you would check for exposed insulation along that wire length or a pinch condition to ground. Also a solder splash about the tube , or a miswire that might been connected to the 6F6 in the past by another person.
::
::
::ZUJ’ing….
::
::
::
::
::73's de Edd
::
::
::
::
::
::
::
::
::s.
Edd/Rene.......Read both of your instructions and adjusted any changes if necessary. I also used the test radio to practice injecting signals and then compared with the Q44. The only change is that there is sound from both the grid and plate of the 6F6 output tube that I said there wasn’t any sound on. I also confirmed that the audio stage is o.k by injecting a signal to the volume control...a nice loud sound. However, I am still not getting any sound from the RF injected signals at all.
Awaiting further instructions.
Job
::Job,
::You sure have been having fun with this set! What part of the country are you in? Perhaps someone in your vicinity would be willing to take a look at your set...sometimes a look-see from an experienced repair person will find the problem a lot faster than via a forum or emails. I'm in south Texas and I'm willing to look at your set if you live in the area.
:
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:Drop by D-FW enroute….and BTW…you will find your boarding pass to be en route to Newfoundland / Nova Scotia
:
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:73's de Edd
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It's usually not a good idea to inject a signal at the plate of the tube because of the voltages involved. If your sig gen doesn't have a blocking capacitor, you could mess up the sig gen.
Please confirm you are trying to inject an internally modulated, 455 kHz RF signal (or whatever the Q44 IF is) at the grid of the 2nd IF amp. If the answer is yes and you aren't getting any sound, then you'll have to start examining everything between the grid of the 2nd IF amp and the center terminal of the volume control. Make sure the 6SK7 2nd IF amp is OK. Try adjusting the 2nd IF transformer trim caps a turn one way and then the other to see if the trans is out of alignment. You've already indicated the primary of the 2nd IF trans is OK because you are getting good voltage at the plate. Check for continuity of the secondary winding.
Thanks
:Job:
:It's usually not a good idea to inject a signal at the plate of the tube because of the voltages involved. If your sig gen doesn't have a blocking capacitor, you could mess up the sig gen.
:
:Please confirm you are trying to inject an internally modulated, 455 kHz RF signal (or whatever the Q44 IF is) at the grid of the 2nd IF amp. If the answer is yes and you aren't getting any sound, then you'll have to start examining everything between the grid of the 2nd IF amp and the center terminal of the volume control. Make sure the 6SK7 2nd IF amp is OK. Try adjusting the 2nd IF transformer trim caps a turn one way and then the other to see if the trans is out of alignment. You've already indicated the primary of the 2nd IF trans is OK because you are getting good voltage at the plate. Check for continuity of the secondary winding.
This is a multi-band radio so how will I know when I am on the AM band, especially when there are no letters/symbols, etc. to tell me which band I’m on?
:Rene-------Thanks for the reminder re sending signal through the plates. Yes, I have the Signal Generator set at 455 kHz and injected a signal through the grid of the 2nd IF amp tube but no sound. I will do the checks you suggested and get back to you tomorrow.
:Thanks
:
:
:
::Job:
::It's usually not a good idea to inject a signal at the plate of the tube because of the voltages involved. If your sig gen doesn't have a blocking capacitor, you could mess up the sig gen.
::
::Please confirm you are trying to inject an internally modulated, 455 kHz RF signal (or whatever the Q44 IF is) at the grid of the 2nd IF amp. If the answer is yes and you aren't getting any sound, then you'll have to start examining everything between the grid of the 2nd IF amp and the center terminal of the volume control. Make sure the 6SK7 2nd IF amp is OK. Try adjusting the 2nd IF transformer trim caps a turn one way and then the other to see if the trans is out of alignment. You've already indicated the primary of the 2nd IF trans is OK because you are getting good voltage at the plate. Check for continuity of the secondary winding.
Have a good day and God bless.
Job
:Job:
:It's usually not a good idea to inject a signal at the plate of the tube because of the voltages involved. If your sig gen doesn't have a blocking capacitor, you could mess up the sig gen.
:
:Please confirm you are trying to inject an internally modulated, 455 kHz RF signal (or whatever the Q44 IF is) at the grid of the 2nd IF amp. If the answer is yes and you aren't getting any sound, then you'll have to start examining everything between the grid of the 2nd IF amp and the center terminal of the volume control. Make sure the 6SK7 2nd IF amp is OK. Try adjusting the 2nd IF transformer trim caps a turn one way and then the other to see if the trans is out of alignment. You've already indicated the primary of the 2nd IF trans is OK because you are getting good voltage at the plate. Check for continuity of the secondary winding.
Hows about going back to the left side of the MUTER power strip resistor and see what the negative derived bias values are now, and also if the 100 V to the right portion of the resistor at its voltage divider source is close to that value now. That resistor had one too many terminals on its right end and all of the divider resistor values were about twice the values as specified for the original unit.
I think that I got the answer on your alignment difficulties from your wife, when I couldn’t get you, she mentioned sending your neighbor….Casper Pee Clod…(lawnmower- fixxerr- upperrr- extraordinaire) out to your radio room, but forgot that you mentioned having to go to town at some time.
After some snooping about, she did remember him coming back out and walking away, cross wiping his hands and muttering something to himself in the order of “ Man…. that thing had one heck of a lot of loose screws in it.”
73's de Edd
That Edd...what a jokester! The electronic comedian! Edd's right...after you finish celebrating, you still have some homework. There's the issue of the funky candohm, aligning at least the IF section of the radio (should give you good eye tube action), replacing any paper caps, especially ones connected to B+ in any way and ground, etc.
The “Saga” continues......Have my celebration behind me and a lawnmower engineer to contend with...LOL...OK where are we....the voltages on that voltage divider are as follows from left to right as per the schematic...negative 25v...negative 3v...zero volts...91v...254v...and 278v.....Keep in mind that on the divider strip in this radio there are six posts, whereas on the schematic there are five.....I’m assuming the zero voltage is the negative terminal.
A couple of other problems.....there are only two AM radio stations in the town I live in and the lower one on the dial scale is 540 and I’m not picking it up....The other AM station is 620 on the dial. I can’t seem to find the right trimmers which will move the stations to the right or left on the dial.
Regards
:That's good news Job! No matter how many sets I work on, it's always good to hear a radio come back to life! I don't know how many sets you have tackled in the past but the Q44 is not your run-of-the-mill radio by any stretch of the imagination.
:
:That Edd...what a jokester! The electronic comedian! Edd's right...after you finish celebrating, you still have some homework. There's the issue of the funky candohm, aligning at least the IF section of the radio (should give you good eye tube action), replacing any paper caps, especially ones connected to B+ in any way and ground, etc.
Now that the set is working, I'd replace the remaining paper caps. Then peform a full blown alignment per the manufacturer's instructions. That may solve your reception problem. Hopefully you are using at least a 10' length of wire for an antenna. I'm not sure of the electronic explanation but many of my sets are "more lively" at the upper end of the BC band.
:
:The “Saga” continues......Have my celebration behind me and a lawnmower engineer to contend with...LOL...OK where are we....the voltages on that voltage divider are as follows from left to right as per the schematic...negative 25v...negative 3v...zero volts...91v...254v...and 278v.....Keep in mind that on the divider strip in this radio there are six posts, whereas on the schematic there are five.....I’m assuming the zero voltage is the negative terminal.
:A couple of other problems.....there are only two AM radio stations in the town I live in and the lower one on the dial scale is 540 and I’m not picking it up....The other AM station is 620 on the dial. I can’t seem to find the right trimmers which will move the stations to the right or left on the dial.
:Regards
:
:
::That's good news Job! No matter how many sets I work on, it's always good to hear a radio come back to life! I don't know how many sets you have tackled in the past but the Q44 is not your run-of-the-mill radio by any stretch of the imagination.
::
::That Edd...what a jokester! The electronic comedian! Edd's right...after you finish celebrating, you still have some homework. There's the issue of the funky candohm, aligning at least the IF section of the radio (should give you good eye tube action), replacing any paper caps, especially ones connected to B+ in any way and ground, etc.
Two coverage’s on this posting then, initially I see that the negative bias values are right in the ball park from the derivation on the left side of that Muter power strip resistor, as for the right side it’s a wee bit low, but try this to trim it on in closer to that spec..
Consult the thumbnail below of the MUTER resistive sections, and then the plot of the resistive values that you gave for the series resistor values of the resistor strip that is currently in the set. I see that I left out the derivation of the 100VDC source buss , which should be showing an orange line buss going down from the junction of the 4890 and 4600 ohm resistors .
Agreed that the right half of the resistor is having one more resistor in the series string, so lets just lift the wire from the right end of the resistor…marked as A vi and move it inwards one position to have it on what I am assuming is to be a terminal void of any wire on it. That then will be bypassing 990 ohms of series resistance and be hitting that voltage divider with a higher B+ level and the 100 VDC buss might then be closer to “0ne hunna volts-sker-ewskies…!!”
Parte deux…..as per your …my 540 is not 540 !!
The tracking on the low band of this set is accomplished by a trimming in of the inductive component of the oscillator coil…this being a “pwemium bwewed” set….. it actually HAS the provisions for doing that…usually sets have an air core with no provision for permitting that fine of a degree of tracking alignment.
Refer to the markup of the green busses that are highlighted in and that should permit you to locate rear wafer of band switch S13 and then zero in on lug # 11 which should let you trace down its sole wire over to the L28 BCB oscillator coil. As that internal slug is adjusted, you should find the station slightly moving up and down the dial scale, or appearing on the dial scale if it was grossly misadjusted such that it was not even letting that 540 station come in. (That’s at the VEWY bottom of the dial scale… BTW… so it may be tuned so low, such that it is not even being picked up) Once you find ye olde station, take tuning knob in hand and tune both sides of the station, using a rocking onto and rocking off of the station action , while simultaneously aurally evaluating its reception strength. You are slowly incrementally adjusting L28 core in one direction while you are doing this , at one point the reception should be progressively weaker as adjusting L28 core. Stop and reverse direction and to end up back where initially starting from and then you would be evaluating in new core position territory. The same effect should show in that direction, so you move back and find the point of strongest reception, and hopefully that will be the point where the dial scale logging will now be closer to the norm……within the parameters of the design variance of the set.
If you find the high end of the dial scale to be in error that manner of BCB local osc correction is provided by the C17 that I have marked up.
Hopefully at night time , you can have some more distant stations rolling in for evaluation.
Standing by…
Voltage divider reference:
Alignment referencing:
73's de Edd
:6 taps but only 5 are used? The zero voltage would be the ground terminal. I can't read the numbers well on my copy but I'd guess the 254 vdc terminal is unused/unnecessary. The other voltages look ok.
:
:Now that the set is working, I'd replace the remaining paper caps. Then peform a full blown alignment per the manufacturer's instructions. That may solve your reception problem. Hopefully you are using at least a 10' length of wire for an antenna. I'm not sure of the electronic explanation but many of my sets are "more lively" at the upper end of the BC band.
::
::The “Saga” continues......Have my celebration behind me and a lawnmower engineer to contend with...LOL...OK where are we....the voltages on that voltage divider are as follows from left to right as per the schematic...negative 25v...negative 3v...zero volts...91v...254v...and 278v.....Keep in mind that on the divider strip in this radio there are six posts, whereas on the schematic there are five.....I’m assuming the zero voltage is the negative terminal.
::A couple of other problems.....there are only two AM radio stations in the town I live in and the lower one on the dial scale is 540 and I’m not picking it up....The other AM station is 620 on the dial. I can’t seem to find the right trimmers which will move the stations to the right or left on the dial.
::Regards
::
::
:::That's good news Job! No matter how many sets I work on, it's always good to hear a radio come back to life! I don't know how many sets you have tackled in the past but the Q44 is not your run-of-the-mill radio by any stretch of the imagination.
:::
:::That Edd...what a jokester! The electronic comedian! Edd's right...after you finish celebrating, you still have some homework. There's the issue of the funky candohm, aligning at least the IF section of the radio (should give you good eye tube action), replacing any paper caps, especially ones connected to B+ in any way and ground, etc.
Also, I haven’t had any success with tuning in the radio station located on the lower end of the scale. I can hear it faintly so I know it’s positioned correctly on the dial scale setting but the trimmers I adjusted wouldn’t bring the sound in any louder. I tried all the trimmers since I wasn’t sure which was the correct trimmer. Eight coils are showing on the schematic but in the chassis itself it is difficult to locate L28 since it seems to be on the same coil as L27 according to the coil and trimmer locator re schematic….block, right side of schematic page.
I’m not sure what it means but when the antenna wire is close to the 6SK6 R.F. tube the speaker goes crazy…..that lower station is loud and clear.
Rene, 90 percent of the caps are replaced and some of the resistors……
I’m attempting to copy and paste a URL so I can show the coils and undercarriage.
Regards.
[URL=http://i292.photobucket.com/albums/mm32/sealionnf/DSC03220.jpg][IMG]http://i292.photobucket.com/albums/mm32/sealionnf/th_DSC03220.jpg[/IMG][/URL]
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:
:Two coverage’s on this posting then, initially I see that the negative bias values are right in the ball park from the derivation on the left side of that Muter power strip resistor, as for the right side it’s a wee bit low, but try this to trim it on in closer to that spec..
:
:
:Consult the thumbnail below of the MUTER resistive sections, and then the plot of the resistive values that you gave for the series resistor values of the resistor strip that is currently in the set. I see that I left out the derivation of the 100VDC source buss , which should be showing an orange line buss going down from the junction of the 4890 and 4600 ohm resistors .
:Agreed that the right half of the resistor is having one more resistor in the series string, so lets just lift the wire from the right end of the resistor…marked as A vi and move it inwards one position to have it on what I am assuming is to be a terminal void of any wire on it. That then will be bypassing 990 ohms of series resistance and be hitting that voltage divider with a higher B+ level and the 100 VDC buss might then be closer to “0ne hunna volts-sker-ewskies…!!”
:
:
:Parte deux…..as per your …my 540 is not 540 !!
:
:
:The tracking on the low band of this set is accomplished by a trimming in of the inductive component of the oscillator coil…this being a “pwemium bwewed” set….. it actually HAS the provisions for doing that…usually sets have an air core with no provision for permitting that fine of a degree of tracking alignment.
:
:Refer to the markup of the green busses that are highlighted in and that should permit you to locate rear wafer of band switch S13 and then zero in on lug # 11 which should let you trace down its sole wire over to the L28 BCB oscillator coil. As that internal slug is adjusted, you should find the station slightly moving up and down the dial scale, or appearing on the dial scale if it was grossly misadjusted such that it was not even letting that 540 station come in. (That’s at the VEWY bottom of the dial scale… BTW… so it may be tuned so low, such that it is not even being picked up) Once you find ye olde station, take tuning knob in hand and tune both sides of the station, using a rocking onto and rocking off of the station action , while simultaneously aurally evaluating its reception strength. You are slowly incrementally adjusting L28 core in one direction while you are doing this , at one point the reception should be progressively weaker as adjusting L28 core. Stop and reverse direction and to end up back where initially starting from and then you would be evaluating in new core position territory. The same effect should show in that direction, so you move back and find the point of strongest reception, and hopefully that will be the point where the dial scale logging will now be closer to the norm……within the parameters of the design variance of the set.
:
:If you find the high end of the dial scale to be in error that manner of BCB local osc correction is provided by the C17 that I have marked up.
:
:Hopefully at night time , you can have some more distant stations rolling in for evaluation.
:
:
:Standing by…
:
:
:
:Voltage divider reference:
:
:
:
:Alignment referencing:
:
:
:
:73's de Edd
:
:
:
:
:
:
:
:
::6 taps but only 5 are used? The zero voltage would be the ground terminal. I can't read the numbers well on my copy but I'd guess the 254 vdc terminal is unused/unnecessary. The other voltages look ok.
::
::Now that the set is working, I'd replace the remaining paper caps. Then peform a full blown alignment per the manufacturer's instructions. That may solve your reception problem. Hopefully you are using at least a 10' length of wire for an antenna. I'm not sure of the electronic explanation but many of my sets are "more lively" at the upper end of the BC band.
:::
:::The “Saga” continues......Have my celebration behind me and a lawnmower engineer to contend with...LOL...OK where are we....the voltages on that voltage divider are as follows from left to right as per the schematic...negative 25v...negative 3v...zero volts...91v...254v...and 278v.....Keep in mind that on the divider strip in this radio there are six posts, whereas on the schematic there are five.....I’m assuming the zero voltage is the negative terminal.
:::A couple of other problems.....there are only two AM radio stations in the town I live in and the lower one on the dial scale is 540 and I’m not picking it up....The other AM station is 620 on the dial. I can’t seem to find the right trimmers which will move the stations to the right or left on the dial.
:::Regards
:::
:::
::::That's good news Job! No matter how many sets I work on, it's always good to hear a radio come back to life! I don't know how many sets you have tackled in the past but the Q44 is not your run-of-the-mill radio by any stretch of the imagination.
::::
::::That Edd...what a jokester! The electronic comedian! Edd's right...after you finish celebrating, you still have some homework. There's the issue of the funky candohm, aligning at least the IF section of the radio (should give you good eye tube action), replacing any paper caps, especially ones connected to B+ in any way and ground, etc.
J
http://i292.photobucket.com/albums/mm32/sealionnf/DSC03220.jpg
:Edd, can’t get at those resistors since they are enclosed in a metal strip I removed this voltage divider metal strip sometime back and the resistors can’t be seen and the metal is crimped together real firm.
:Also, I haven’t had any success with tuning in the radio station located on the lower end of the scale. I can hear it faintly so I know it’s positioned correctly on the dial scale setting but the trimmers I adjusted wouldn’t bring the sound in any louder. I tried all the trimmers since I wasn’t sure which was the correct trimmer. Eight coils are showing on the schematic but in the chassis itself it is difficult to locate L28 since it seems to be on the same coil as L27 according to the coil and trimmer locator re schematic….block, right side of schematic page.
:I’m not sure what it means but when the antenna wire is close to the 6SK6 R.F. tube the speaker goes crazy…..that lower station is loud and clear.
:Rene, 90 percent of the caps are replaced and some of the resistors……
:I’m attempting to copy and paste a URL so I can show the coils and undercarriage.
:Regards.
:[URL=http://i292.photobucket.com/albums/mm32/sealionnf/DSC03220.jpg][IMG]http://i292.photobucket.com/albums/mm32/sealionnf/th_DSC03220.jpg[/IMG][/URL]
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::Two coverage’s on this posting then, initially I see that the negative bias values are right in the ball park from the derivation on the left side of that Muter power strip resistor, as for the right side it’s a wee bit low, but try this to trim it on in closer to that spec..
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::Consult the thumbnail below of the MUTER resistive sections, and then the plot of the resistive values that you gave for the series resistor values of the resistor strip that is currently in the set. I see that I left out the derivation of the 100VDC source buss , which should be showing an orange line buss going down from the junction of the 4890 and 4600 ohm resistors .
::Agreed that the right half of the resistor is having one more resistor in the series string, so lets just lift the wire from the right end of the resistor…marked as A vi and move it inwards one position to have it on what I am assuming is to be a terminal void of any wire on it. That then will be bypassing 990 ohms of series resistance and be hitting that voltage divider with a higher B+ level and the 100 VDC buss might then be closer to “0ne hunna volts-sker-ewskies…!!”
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::Parte deux…..as per your …my 540 is not 540 !!
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::The tracking on the low band of this set is accomplished by a trimming in of the inductive component of the oscillator coil…this being a “pwemium bwewed” set….. it actually HAS the provisions for doing that…usually sets have an air core with no provision for permitting that fine of a degree of tracking alignment.
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::Refer to the markup of the green busses that are highlighted in and that should permit you to locate rear wafer of band switch S13 and then zero in on lug # 11 which should let you trace down its sole wire over to the L28 BCB oscillator coil. As that internal slug is adjusted, you should find the station slightly moving up and down the dial scale, or appearing on the dial scale if it was grossly misadjusted such that it was not even letting that 540 station come in. (That’s at the VEWY bottom of the dial scale… BTW… so it may be tuned so low, such that it is not even being picked up) Once you find ye olde station, take tuning knob in hand and tune both sides of the station, using a rocking onto and rocking off of the station action , while simultaneously aurally evaluating its reception strength. You are slowly incrementally adjusting L28 core in one direction while you are doing this , at one point the reception should be progressively weaker as adjusting L28 core. Stop and reverse direction and to end up back where initially starting from and then you would be evaluating in new core position territory. The same effect should show in that direction, so you move back and find the point of strongest reception, and hopefully that will be the point where the dial scale logging will now be closer to the norm……within the parameters of the design variance of the set.
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::If you find the high end of the dial scale to be in error that manner of BCB local osc correction is provided by the C17 that I have marked up.
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::Hopefully at night time , you can have some more distant stations rolling in for evaluation.
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::Standing by…
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::Voltage divider reference:
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::Alignment referencing:
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::73's de Edd
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:::6 taps but only 5 are used? The zero voltage would be the ground terminal. I can't read the numbers well on my copy but I'd guess the 254 vdc terminal is unused/unnecessary. The other voltages look ok.
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:::Now that the set is working, I'd replace the remaining paper caps. Then peform a full blown alignment per the manufacturer's instructions. That may solve your reception problem. Hopefully you are using at least a 10' length of wire for an antenna. I'm not sure of the electronic explanation but many of my sets are "more lively" at the upper end of the BC band.
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::::The “Saga” continues......Have my celebration behind me and a lawnmower engineer to contend with...LOL...OK where are we....the voltages on that voltage divider are as follows from left to right as per the schematic...negative 25v...negative 3v...zero volts...91v...254v...and 278v.....Keep in mind that on the divider strip in this radio there are six posts, whereas on the schematic there are five.....I’m assuming the zero voltage is the negative terminal.
::::A couple of other problems.....there are only two AM radio stations in the town I live in and the lower one on the dial scale is 540 and I’m not picking it up....The other AM station is 620 on the dial. I can’t seem to find the right trimmers which will move the stations to the right or left on the dial.
::::Regards
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:::::That's good news Job! No matter how many sets I work on, it's always good to hear a radio come back to life! I don't know how many sets you have tackled in the past but the Q44 is not your run-of-the-mill radio by any stretch of the imagination.
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:::::That Edd...what a jokester! The electronic comedian! Edd's right...after you finish celebrating, you still have some homework. There's the issue of the funky candohm, aligning at least the IF section of the radio (should give you good eye tube action), replacing any paper caps, especially ones connected to B+ in any way and ground, etc.
:I’m not sure what it means but when the antenna wire is close to the 6SK6 R.F. tube the speaker goes crazy…..that lower station is loud and clear.
73's de Edd
I won’t pretend to have a handle as to your instructions re mixer sections, etc. but when I placed my finger on the terminal of the middle section of the tuner the station on the low end of the dial came in loud and clear. Also, I connected a lead from the antenna post to that centre terminal of this centre section and all stations are just great. Now for the question....I realize I am bypassing a whole lot of things by doing this but why can’t I string a wire between those two points and operate this radio???? I am attached a site where you can see what I have done so just copy and paste.
Regards
http://i292.photobucket.com/albums/mm32/sealionnf/DSC03230.jpg
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:73's de Edd
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I'm not sure what the middle section is of your tuning cap but I suspect it is the input of your mixer/converter. That means the RF section is inoperative due to an open coil or bandswitch. Do this little test...oonnect your antenna wire normally and switch over to a shortwave band and tune in to a decent signal. Then touch the middle section. If volume doesn't improve, then the RF section IS working and the fault lies in the coils or bandswitch contacts used in the BCB circuit.
Your candohm section readings are still somewhat confusing and you have 6 readings when you should only have 5. The negative voltages sound OK. If I'm not mistaken, there should be a wire on the terminal where ~100 volts is present. That wire should be supplying various screen grid voltages.
:Edd, I moved that wire over one position as per your instructions and the voltages are as follows from left to right as per schematic...minus 24v/ minus 3v/ zero volts/ 95v/ 264v/ 264v.
:I won’t pretend to have a handle as to your instructions re mixer sections, etc. but when I placed my finger on the terminal of the middle section of the tuner the station on the low end of the dial came in loud and clear. Also, I connected a lead from the antenna post to that centre terminal of this centre section and all stations are just great. Now for the question....I realize I am bypassing a whole lot of things by doing this but why can’t I string a wire between those two points and operate this radio???? I am attached a site where you can see what I have done so just copy and paste.
:Regards
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:http://i292.photobucket.com/albums/mm32/sealionnf/DSC03230.jpg
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::73's de Edd
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After a VEWY careful perusal of your last photo…..Found your problem…..you have a broken dial cord……
Goooood Lawwwd ….I was happy with the bottom chassis, but the top chassis is atrocious, hope its just a built up layer of micro dust, as is on top of the IF transformers, and not rust also.
Roll out the “409”, a stiff hog bristle brush and HOT water and do a scrub down and a “sling drying” and a final dry in a 200-250 degree oven in its cool down cycle.
Since I now have the top and bottom photos for reference I can see that the front edge of the tuning condenser is the RF section, the mid section is the mixer section, and the innermost chassis position is the tuning condensers oscillator section.
Consulting my markup below, the orange highlighted area is currently functioning for you, now try taking 3 or so of those test leads and daisy chaining them for additional length and then initially clip one onto the Plate (#8) of the 6SK7 RF tube and string the leads vertical to be an antenna…..but not connecting to anything with the other free end clip… and see if we get reception. That would signify that the signal is punching thru the L19-20 RF plate transformer.
Then move the clip lead over to the 1st grid (#4) of the 6SK7RF amp. … and see if we get any reception from that point.
If no, on the prior tests, check the DC voltage on the RF 6SK7’s screen at pin #6 and its plate at #8.
Typically expecting in the range of ~99VDC and ~230VDC…
Then you swap out the 6SK7 RF and IF tubes and confirm that the prior 6SK7 RF tube is functioning OK in the IF slot.
Lastly, on your walking the wire over one terminal, i don't have your "before" reading of the ~100 VDC supply tapoff, but would now expect it to be a tad higher, at least as high as it is going to be with the present terminal strip resistor series, which seems to be good enough for you.
73's de Edd
Also, my question was answered re the hookup from the antenna post to the middle of the tuner when I couldn’t receive shortwave stations....oh well, it was a try.
The reason I gave six voltage readings for that voltage resistor strip is because in actuality there are six terminals on that strip but only five showing on the schematic......Edd I just read your posting and will go and follow your instructions but first the original voltages and the new readings after moving the wire over one terminal.....old readings in brackets:
minus 24v (minus 25v), minus 3v (minus 3v), zero volts (zero volts), 94v (91v), 262v (254), 262v (278)
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:After a VEWY careful perusal of your last photo…..Found your problem…..you have a broken dial cord……
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:Goooood Lawwwd ….I was happy with the bottom chassis, but the top chassis is atrocious, hope its just a built up layer of micro dust, as is on top of the IF transformers, and not rust also.
:
:Roll out the “409”, a stiff hog bristle brush and HOT water and do a scrub down and a “sling drying” and a final dry in a 200-250 degree oven in its cool down cycle.
:
:Since I now have the top and bottom photos for reference I can see that the front edge of the tuning condenser is the RF section, the mid section is the mixer section, and the innermost chassis position is the tuning condensers oscillator section.
:
:
:Consulting my markup below, the orange highlighted area is currently functioning for you, now try taking 3 or so of those test leads and daisy chaining them for additional length and then initially clip one onto the Plate (#8) of the 6SK7 RF tube and string the leads vertical to be an antenna…..but not connecting to anything with the other free end clip… and see if we get reception. That would signify that the signal is punching thru the L19-20 RF plate transformer.
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:Then move the clip lead over to the 1st grid (#4) of the 6SK7RF amp. … and see if we get any reception from that point.
: If no, on the prior tests, check the DC voltage on the RF 6SK7’s screen at pin #6 and its plate at #8.
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:Typically expecting in the range of ~99VDC and ~230VDC…
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:Then you swap out the 6SK7 RF and IF tubes and confirm that the prior 6SK7 RF tube is functioning OK in the IF slot.
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:Lastly, on your walking the wire over one terminal, i don't have your "before" reading of the ~100 VDC supply tapoff, but would now expect it to be a tad higher, at least as high as it is going to be with the present terminal strip resistor series, which seems to be good enough for you.
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:73's de Edd
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Then the RF section works but your BCB problem lies along the circuitry that Edd has highlighted for you...all the way from the antenna to the signal grid of the converter. Get out that ohmeter and start doing more continuity tests. You likely have an open coil somewhere or dirty bandswitch connections.
According to the schematic, you should be using the taps where the following voltages exist (or close to them) on your non-original candohm: -22, -2.5, 0, +100, +275. Your terminal with readings of 262 and 254 volts looks like it should have no connection. You are hopefully still planning on replacing this entire resistor string with discrete resistors.
:Rene------With the antenna connected normally and a station tuned in on a shortwave band I touched the terminal on the middle section of the tuner.....the volume did not increase, actually it decreased a little.
:Also, my question was answered re the hookup from the antenna post to the middle of the tuner when I couldn’t receive shortwave stations....oh well, it was a try.
:The reason I gave six voltage readings for that voltage resistor strip is because in actuality there are six terminals on that strip but only five showing on the schematic......Edd I just read your posting and will go and follow your instructions but first the original voltages and the new readings after moving the wire over one terminal.....old readings in brackets:
:minus 24v (minus 25v), minus 3v (minus 3v), zero volts (zero volts), 94v (91v), 262v (254), 262v (278)
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::After a VEWY careful perusal of your last photo…..Found your problem…..you have a broken dial cord……
::
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::Goooood Lawwwd ….I was happy with the bottom chassis, but the top chassis is atrocious, hope its just a built up layer of micro dust, as is on top of the IF transformers, and not rust also.
::
::Roll out the “409”, a stiff hog bristle brush and HOT water and do a scrub down and a “sling drying” and a final dry in a 200-250 degree oven in its cool down cycle.
::
::Since I now have the top and bottom photos for reference I can see that the front edge of the tuning condenser is the RF section, the mid section is the mixer section, and the innermost chassis position is the tuning condensers oscillator section.
::
::
::Consulting my markup below, the orange highlighted area is currently functioning for you, now try taking 3 or so of those test leads and daisy chaining them for additional length and then initially clip one onto the Plate (#8) of the 6SK7 RF tube and string the leads vertical to be an antenna…..but not connecting to anything with the other free end clip… and see if we get reception. That would signify that the signal is punching thru the L19-20 RF plate transformer.
::
::Then move the clip lead over to the 1st grid (#4) of the 6SK7RF amp. … and see if we get any reception from that point.
:: If no, on the prior tests, check the DC voltage on the RF 6SK7’s screen at pin #6 and its plate at #8.
::
::Typically expecting in the range of ~99VDC and ~230VDC…
::
::Then you swap out the 6SK7 RF and IF tubes and confirm that the prior 6SK7 RF tube is functioning OK in the IF slot.
::
::
::Lastly, on your walking the wire over one terminal, i don't have your "before" reading of the ~100 VDC supply tapoff, but would now expect it to be a tad higher, at least as high as it is going to be with the present terminal strip resistor series, which seems to be good enough for you.
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::73's de Edd
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Swapped tubes and “BINGO” all stations came in loud and clear……I can’t figure out what is going on but fellows I do have my stations……Rene, I am ordering resistors but having trouble finding the exact wattage….is their a tolerance? I know you can’t go lower but how much higher in watts would be permissible??
Edd, I’ll work on the top of that chassis too….Also there is very useful information in this tread which I have to print for future reference…Again thanks for all your patience and assistance…whewww, now I can really celebrate.
Regards
:Job,
:Then the RF section works but your BCB problem lies along the circuitry that Edd has highlighted for you...all the way from the antenna to the signal grid of the converter. Get out that ohmeter and start doing more continuity tests. You likely have an open coil somewhere or dirty bandswitch connections.
:
:According to the schematic, you should be using the taps where the following voltages exist (or close to them) on your non-original candohm: -22, -2.5, 0, +100, +275. Your terminal with readings of 262 and 254 volts looks like it should have no connection. You are hopefully still planning on replacing this entire resistor string with discrete resistors.
:
::Rene------With the antenna connected normally and a station tuned in on a shortwave band I touched the terminal on the middle section of the tuner.....the volume did not increase, actually it decreased a little.
::Also, my question was answered re the hookup from the antenna post to the middle of the tuner when I couldn’t receive shortwave stations....oh well, it was a try.
::The reason I gave six voltage readings for that voltage resistor strip is because in actuality there are six terminals on that strip but only five showing on the schematic......Edd I just read your posting and will go and follow your instructions but first the original voltages and the new readings after moving the wire over one terminal.....old readings in brackets:
::minus 24v (minus 25v), minus 3v (minus 3v), zero volts (zero volts), 94v (91v), 262v (254), 262v (278)
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:::After a VEWY careful perusal of your last photo…..Found your problem…..you have a broken dial cord……
:::
:::
:::Goooood Lawwwd ….I was happy with the bottom chassis, but the top chassis is atrocious, hope its just a built up layer of micro dust, as is on top of the IF transformers, and not rust also.
:::
:::Roll out the “409”, a stiff hog bristle brush and HOT water and do a scrub down and a “sling drying” and a final dry in a 200-250 degree oven in its cool down cycle.
:::
:::Since I now have the top and bottom photos for reference I can see that the front edge of the tuning condenser is the RF section, the mid section is the mixer section, and the innermost chassis position is the tuning condensers oscillator section.
:::
:::
:::Consulting my markup below, the orange highlighted area is currently functioning for you, now try taking 3 or so of those test leads and daisy chaining them for additional length and then initially clip one onto the Plate (#8) of the 6SK7 RF tube and string the leads vertical to be an antenna…..but not connecting to anything with the other free end clip… and see if we get reception. That would signify that the signal is punching thru the L19-20 RF plate transformer.
:::
:::Then move the clip lead over to the 1st grid (#4) of the 6SK7RF amp. … and see if we get any reception from that point.
::: If no, on the prior tests, check the DC voltage on the RF 6SK7’s screen at pin #6 and its plate at #8.
:::
:::Typically expecting in the range of ~99VDC and ~230VDC…
:::
:::Then you swap out the 6SK7 RF and IF tubes and confirm that the prior 6SK7 RF tube is functioning OK in the IF slot.
:::
:::
:::Lastly, on your walking the wire over one terminal, i don't have your "before" reading of the ~100 VDC supply tapoff, but would now expect it to be a tad higher, at least as high as it is going to be with the present terminal strip resistor series, which seems to be good enough for you.
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:::73's de Edd
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:Edd------Followed your instructions and clipped onto plate No. 8, 6SK7 RF and received good reception...clipped onto the 1st grid, 6SK7RF amp....no reception......checked voltages of screen and plate and got respectively...103v and 235v.
:Swapped tubes and “BINGO” all stations came in loud and clear……I can’t figure out what is going on but fellows I do have my stations……Rene, I am ordering resistors but having trouble finding the exact wattage….is their a tolerance? I know you can’t go lower but how much higher in watts would be permissible??
:Edd, I’ll work on the top of that chassis too….Also there is very useful information in this tread which I have to print for future reference…Again thanks for all your patience and assistance…whewww, now I can really celebrate.
:Regards
:
:
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::Job,
::Then the RF section works but your BCB problem lies along the circuitry that Edd has highlighted for you...all the way from the antenna to the signal grid of the converter. Get out that ohmeter and start doing more continuity tests. You likely have an open coil somewhere or dirty bandswitch connections.
::
::According to the schematic, you should be using the taps where the following voltages exist (or close to them) on your non-original candohm: -22, -2.5, 0, +100, +275. Your terminal with readings of 262 and 254 volts looks like it should have no connection. You are hopefully still planning on replacing this entire resistor string with discrete resistors.
::
:::Rene------With the antenna connected normally and a station tuned in on a shortwave band I touched the terminal on the middle section of the tuner.....the volume did not increase, actually it decreased a little.
:::Also, my question was answered re the hookup from the antenna post to the middle of the tuner when I couldn’t receive shortwave stations....oh well, it was a try.
:::The reason I gave six voltage readings for that voltage resistor strip is because in actuality there are six terminals on that strip but only five showing on the schematic......Edd I just read your posting and will go and follow your instructions but first the original voltages and the new readings after moving the wire over one terminal.....old readings in brackets:
:::minus 24v (minus 25v), minus 3v (minus 3v), zero volts (zero volts), 94v (91v), 262v (254), 262v (278)
:::
:::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::
::::After a VEWY careful perusal of your last photo…..Found your problem…..you have a broken dial cord……
::::
::::
::::Goooood Lawwwd ….I was happy with the bottom chassis, but the top chassis is atrocious, hope its just a built up layer of micro dust, as is on top of the IF transformers, and not rust also.
::::
::::Roll out the “409”, a stiff hog bristle brush and HOT water and do a scrub down and a “sling drying” and a final dry in a 200-250 degree oven in its cool down cycle.
::::
::::Since I now have the top and bottom photos for reference I can see that the front edge of the tuning condenser is the RF section, the mid section is the mixer section, and the innermost chassis position is the tuning condensers oscillator section.
::::
::::
::::Consulting my markup below, the orange highlighted area is currently functioning for you, now try taking 3 or so of those test leads and daisy chaining them for additional length and then initially clip one onto the Plate (#8) of the 6SK7 RF tube and string the leads vertical to be an antenna…..but not connecting to anything with the other free end clip… and see if we get reception. That would signify that the signal is punching thru the L19-20 RF plate transformer.
::::
::::Then move the clip lead over to the 1st grid (#4) of the 6SK7RF amp. … and see if we get any reception from that point.
:::: If no, on the prior tests, check the DC voltage on the RF 6SK7’s screen at pin #6 and its plate at #8.
::::
::::Typically expecting in the range of ~99VDC and ~230VDC…
::::
::::Then you swap out the 6SK7 RF and IF tubes and confirm that the prior 6SK7 RF tube is functioning OK in the IF slot.
::::
::::
::::Lastly, on your walking the wire over one terminal, i don't have your "before" reading of the ~100 VDC supply tapoff, but would now expect it to be a tad higher, at least as high as it is going to be with the present terminal strip resistor series, which seems to be good enough for you.
::::
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::::73's de Edd
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Job
:That's great Job! Sounds like there might have been a bad pin connection and swapping tubes fixed it. Regarding the wattage for the candohm sections, I did some calcs in an earlier thread based on known voltages and resistances. If you can't find the thread, I'll re-do the calcs...basic ohms law stuff. To answer your question, the bigger the wattage, the cooler the resistor will run...no such thing as too much wattage for that reason but bigger watts means more $ and also more space needed to mount them.
:
::Edd------Followed your instructions and clipped onto plate No. 8, 6SK7 RF and received good reception...clipped onto the 1st grid, 6SK7RF amp....no reception......checked voltages of screen and plate and got respectively...103v and 235v.
::Swapped tubes and “BINGO” all stations came in loud and clear……I can’t figure out what is going on but fellows I do have my stations……Rene, I am ordering resistors but having trouble finding the exact wattage….is their a tolerance? I know you can’t go lower but how much higher in watts would be permissible??
::Edd, I’ll work on the top of that chassis too….Also there is very useful information in this tread which I have to print for future reference…Again thanks for all your patience and assistance…whewww, now I can really celebrate.
::Regards
::
::
::
:::Job,
:::Then the RF section works but your BCB problem lies along the circuitry that Edd has highlighted for you...all the way from the antenna to the signal grid of the converter. Get out that ohmeter and start doing more continuity tests. You likely have an open coil somewhere or dirty bandswitch connections.
:::
:::According to the schematic, you should be using the taps where the following voltages exist (or close to them) on your non-original candohm: -22, -2.5, 0, +100, +275. Your terminal with readings of 262 and 254 volts looks like it should have no connection. You are hopefully still planning on replacing this entire resistor string with discrete resistors.
:::
::::Rene------With the antenna connected normally and a station tuned in on a shortwave band I touched the terminal on the middle section of the tuner.....the volume did not increase, actually it decreased a little.
::::Also, my question was answered re the hookup from the antenna post to the middle of the tuner when I couldn’t receive shortwave stations....oh well, it was a try.
::::The reason I gave six voltage readings for that voltage resistor strip is because in actuality there are six terminals on that strip but only five showing on the schematic......Edd I just read your posting and will go and follow your instructions but first the original voltages and the new readings after moving the wire over one terminal.....old readings in brackets:
::::minus 24v (minus 25v), minus 3v (minus 3v), zero volts (zero volts), 94v (91v), 262v (254), 262v (278)
::::
::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::
:::::After a VEWY careful perusal of your last photo…..Found your problem…..you have a broken dial cord……
:::::
:::::
:::::Goooood Lawwwd ….I was happy with the bottom chassis, but the top chassis is atrocious, hope its just a built up layer of micro dust, as is on top of the IF transformers, and not rust also.
:::::
:::::Roll out the “409”, a stiff hog bristle brush and HOT water and do a scrub down and a “sling drying” and a final dry in a 200-250 degree oven in its cool down cycle.
:::::
:::::Since I now have the top and bottom photos for reference I can see that the front edge of the tuning condenser is the RF section, the mid section is the mixer section, and the innermost chassis position is the tuning condensers oscillator section.
:::::
:::::
:::::Consulting my markup below, the orange highlighted area is currently functioning for you, now try taking 3 or so of those test leads and daisy chaining them for additional length and then initially clip one onto the Plate (#8) of the 6SK7 RF tube and string the leads vertical to be an antenna…..but not connecting to anything with the other free end clip… and see if we get reception. That would signify that the signal is punching thru the L19-20 RF plate transformer.
:::::
:::::Then move the clip lead over to the 1st grid (#4) of the 6SK7RF amp. … and see if we get any reception from that point.
::::: If no, on the prior tests, check the DC voltage on the RF 6SK7’s screen at pin #6 and its plate at #8.
:::::
:::::Typically expecting in the range of ~99VDC and ~230VDC…
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:::::Then you swap out the 6SK7 RF and IF tubes and confirm that the prior 6SK7 RF tube is functioning OK in the IF slot.
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:::::Lastly, on your walking the wire over one terminal, i don't have your "before" reading of the ~100 VDC supply tapoff, but would now expect it to be a tad higher, at least as high as it is going to be with the present terminal strip resistor series, which seems to be good enough for you.
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:::::73's de Edd
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Such a deal already, on the Ocean State Power Ree-sistors,
There is the negative bias leg that will be needing a 22 ohm @ 5 watt unit that is shown as a stock item value.
Its series companion of 135 ohms will be needing a 150 ohm @ 5 watt with one of the 1500 ohm 2 watt metal film resistors shunted across it to end up with a 136 ohm value.
Over on the sub B+ divider pair there is a 3900 ohm @ 10 watts unit which is a stock value item, and for its companion, select another 3900 ohm @ 10 watts unit , and take one of their 33K ohm 2 watt metal film units to shunt across that unit to give you 3487 ohms.
When I use that type of resistor, I will take some aluminum bar stock and lay the resistors out in a line and then clamp them to chassis with the bar stock. Leave the labeling so that it is visible from the bottom of the chassis and that leaves the cavity with its vitreous frit fill in, such that it won’t be anywhere near the chassis. I also use a pore filling film of Dow Corning between the chassis and the bar stock for optimizing heat transfer.
73's de Edd
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:Such a deal already, on the Ocean State Power Ree-sistors,
:
:There is the negative bias leg that will be needing a 22 ohm @ 5 watt unit that is shown as a stock item value.
:
:Its series companion of 135 ohms will be needing a 150 ohm @ 5 watt with one of the 1500 ohm 2 watt metal film resistors shunted across it to end up with a 136 ohm value.
:
:Over on the sub B+ divider pair there is a 3900 ohm @ 10 watts unit which is a stock value item, and for its companion, select another 3900 ohm @ 10 watts unit , and take one of their 33K ohm 2 watt metal film units to shunt across that unit to give you 3487 ohms.
:
:
:
:When I use that type of resistor, I will take some aluminum bar stock and lay the resistors out in a line and then clamp them to chassis with the bar stock. Leave the labeling so that it is visible from the bottom of the chassis and that leaves the cavity with its vitreous frit fill in, such that it won’t be anywhere near the chassis. I also use a pore filling film of Dow Corning between the chassis and the bar stock for optimizing heat transfer.
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:73's de Edd
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