Hello,
I have an RCA model 56X3. I have recapped the radio and tuned the I.F.'s. It plays and will pick up stations late at night, not very good during the day. Still has static on weak stations. Is there a recommendation for an antenna for any AM tube radio?

:Hello,
:I have an RCA model 56X3. I have recapped the radio and tuned the I.F.'s. It plays and will pick up stations late at night, not very good during the day. Still has static on weak stations. Is there a recommendation for an antenna for any AM tube radio?
:
Unless you live WAY out in the country you should have the same sensitivity during the day as at night. In fact at night the band should be crowded. I believe you have a gain issue somewhere in the front end. That set has an extra RF amplifier, so it should have LOTS of gain. Some of the suspects might be the antenna coil connections, tuning cap trimmer, weak 1st RF amp tube or leaky grid leak resistor. I hope you checked the operation after every cap substitution. You could have a bad solder connection. Also, I'd double check the alignment. Do you have a generator and ACVTVM?
I'd suspect these before the need of an external antenna.
Hope this helps,
Terry

::Hello,
::I have an RCA model 56X3. I have recapped the radio and tuned the I.F.'s. It plays and will pick up stations late at night, not very good during the day. Still has static on weak stations. Is there a recommendation for an antenna for any AM tube radio?
::
:
:Hi Mitch-
:Unless you live WAY out in the country you should have the same sensitivity during the day as at night. In fact at night the band should be crowded. I believe you have a gain issue somewhere in the front end. That set has an extra RF amplifier, so it should have LOTS of gain. Some of the suspects might be the antenna coil connections, tuning cap trimmer, weak 1st RF amp tube or leaky grid leak resistor. I hope you checked the operation after every cap substitution. You could have a bad solder connection. Also, I'd double check the alignment. Do you have a generator and ACVTVM?
:I'd suspect these before the need of an external antenna.
:Hope this helps,
:Terry
:
Terry,

I live over forty miles in the country on a farm. I will check the antenna coil circuit as well as the other components and areas you pointed out.When i first got the radio it played. First changed the DC caps to eliminate the 60 hz hum. Tested the radio with each cap change and it worked each time. I will recheck the alignment. I have a function signal generator and am injecting a 455 KHZ signwave directly into the antenna. I also use a 100 MHZ scope.

Thanks for the help, Any other suggestions are welcome. I will follow with you after more troubshooting.

Mitch

Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.

:Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
:
Terry

::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
::
:
:Some people don't realize that the antenna coil is a coupling coil just like the IF transformers. They think it's just an antenna wire. The secondary needs to form a loop to complete the R/C tuning circuit. If it's open in CAN still operate, due to stray capacitance, but not very efficiently.
:
:Keep us posted.
:Terry
:
Terry,

Antenna coil is fine, omic according to schematic is correct. Will chase front end gain issue.

If you have more advice i am open.

Mitch

:Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
:
Warren,

Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.

Thanks, and please respond to trail.

Mitch

::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
::
:Warren,
:
:Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.
:
:Thanks, and please respond to trail.
:
:Mitch
:
I was looking at the wrong info. The Riders service info on 15-26 suggests a RF amplifier. Oops. Anyway, check the voltages around the 12SG7 converter, especially the cathode, which should be 4.7, also the plate. A low voltage there would indicate a leaky cap that you missed, some problem with the primary of the 1st IF or a change in the value of R1.
Let us know.
Terry
T.

:::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
:::
::Warren,
::
::Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.
::
::Thanks, and please respond to trail.
::
::Mitch
::
:I was looking at the wrong info. The Riders service info on 15-26 suggests a RF amplifier. Oops. Anyway, check the voltages around the 12SG7 converter, especially the cathode, which should be 4.7, also the plate. A low voltage there would indicate a leaky cap that you missed, some problem with the primary of the 1st IF or a change in the value of R1.
:Let us know.
:Terry
:T.
:

::::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
::::
:::Warren,
:::
:::Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.
:::
:::Thanks, and please respond to trail.
:::
:::Mitch
:::
::I was looking at the wrong info. The Riders service info on 15-26 suggests a RF amplifier. Oops. Anyway, check the voltages around the 12SG7 converter, especially the cathode, which should be 4.7, also the plate. A low voltage there would indicate a leaky cap that you missed, some problem with the primary of the 1st IF or a change in the value of R1.
::Let us know.
::Terry
::T.
::
:
:Terry,
:
:Will check this out tonight and let you know.
:
:Mitch
:
Terry,

I am about to work on the radio now and i have a question as long as you might be looking at the schematic. I changed all of the paper caps except one, C8. The part list calls for a .0003 MFD, observation of the cap reads .o35 MFD 600 Volt. The cap is chipped on one end. I am waiting for a cap kit from Just Radios to replace this one. Could this cap be my headache?
Also need to verify that the model # i gave was the RCA 56X3?

Mitch

C-8 is part of the tone circuit.

:::::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
:::::
::::Warren,
::::
::::Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.
::::
::::Thanks, and please respond to trail.
::::
::::Mitch
::::
:::I was looking at the wrong info. The Riders service info on 15-26 suggests a RF amplifier. Oops. Anyway, check the voltages around the 12SG7 converter, especially the cathode, which should be 4.7, also the plate. A low voltage there would indicate a leaky cap that you missed, some problem with the primary of the 1st IF or a change in the value of R1.
:::Let us know.
:::Terry
:::T.
:::
::
::Terry,
::
::Will check this out tonight and let you know.
::
::Mitch
::
:Terry,
:
:I am about to work on the radio now and i have a question as long as you might be looking at the schematic. I changed all of the paper caps except one, C8. The part list calls for a .0003 MFD, observation of the cap reads .o35 MFD 600 Volt. The cap is chipped on one end. I am waiting for a cap kit from Just Radios to replace this one. Could this cap be my headache?
:Also need to verify that the model # i gave was the RCA 56X3?
:
:Mitch
:
I'd print it out.
Terry

::::::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
::::::
:::::Warren,
:::::
:::::Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.
:::::
:::::Thanks, and please respond to trail.
:::::
:::::Mitch
:::::
::::I was looking at the wrong info. The Riders service info on 15-26 suggests a RF amplifier. Oops. Anyway, check the voltages around the 12SG7 converter, especially the cathode, which should be 4.7, also the plate. A low voltage there would indicate a leaky cap that you missed, some problem with the primary of the 1st IF or a change in the value of R1.
::::Let us know.
::::Terry
::::T.
::::
:::
:::Terry,
:::
:::Will check this out tonight and let you know.
:::
:::Mitch
:::
::Terry,
::
::I am about to work on the radio now and i have a question as long as you might be looking at the schematic. I changed all of the paper caps except one, C8. The part list calls for a .0003 MFD, observation of the cap reads .o35 MFD 600 Volt. The cap is chipped on one end. I am waiting for a cap kit from Just Radios to replace this one. Could this cap be my headache?
::Also need to verify that the model # i gave was the RCA 56X3?
::
::Mitch
::
:
:Go to the "Resources" tab at the top of this page. Scroll down and click on RCA Victor Co.Inc. Scroll down and click on 56X3. Click on the eye. There are 3 choices. Choose the last one- Riders vol. 15-31. That will be the schematic you need.
:I'd print it out.
:Terry
:
More-
I notice that there are some notes at the bottom of the service info page. Apparently the position of some leads are critical. I have a feeling that these are mostly concerned with induced hum, but you never know. I'd try and dress the wires as indicated. See if that helps.
T.

:::::::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
:::::::
::::::Warren,
::::::
::::::Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.
::::::
::::::Thanks, and please respond to trail.
::::::
::::::Mitch
::::::
:::::I was looking at the wrong info. The Riders service info on 15-26 suggests a RF amplifier. Oops. Anyway, check the voltages around the 12SG7 converter, especially the cathode, which should be 4.7, also the plate. A low voltage there would indicate a leaky cap that you missed, some problem with the primary of the 1st IF or a change in the value of R1.
:::::Let us know.
:::::Terry
:::::T.
:::::
::::
::::Terry,
::::
::::Will check this out tonight and let you know.
::::
::::Mitch
::::
:::Terry,
:::
:::I am about to work on the radio now and i have a question as long as you might be looking at the schematic. I changed all of the paper caps except one, C8. The part list calls for a .0003 MFD, observation of the cap reads .035 MFD 600 Volt. The cap is chipped on one end. I am waiting for a cap kit from Just Radios to replace this one. Could this cap be my headache?
:::Also need to verify that the model # i gave was the RCA 56X3?
:::
:::Mitch
:::
::
::Go to the "Resources" tab at the top of this page. Scroll down and click on RCA Victor Co.Inc. Scroll down and click on 56X3. Click on the eye. There are 3 choices. Choose the last one- Riders vol. 15-31. That will be the schematic you need.
::I'd print it out.
::Terry
::
:More-
:I notice that there are some notes at the bottom of the service info page. Apparently the position of some leads are critical. I have a feeling that these are mostly concerned with induced hum, but you never know. I'd try and dress the wires as indicated. See if that helps.
:T.
:
Whats your thought on the static coming from the C8 cap that i have not replaced yet?
I will try the dress up of components according to Riders 15-31.

Mitch

::::::::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
::::::::
:::::::Warren,
:::::::
:::::::Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.
:::::::
:::::::Thanks, and please respond to trail.
:::::::
:::::::Mitch
:::::::
::::::I was looking at the wrong info. The Riders service info on 15-26 suggests a RF amplifier. Oops. Anyway, check the voltages around the 12SG7 converter, especially the cathode, which should be 4.7, also the plate. A low voltage there would indicate a leaky cap that you missed, some problem with the primary of the 1st IF or a change in the value of R1.
::::::Let us know.
::::::Terry
::::::T.
::::::
:::::
:::::Terry,
:::::
:::::Will check this out tonight and let you know.
:::::
:::::Mitch
:::::
::::Terry,
::::
::::I am about to work on the radio now and i have a question as long as you might be looking at the schematic. I changed all of the paper caps except one, C8. The part list calls for a .0003 MFD, observation of the cap reads .035 MFD 600 Volt. The cap is chipped on one end. I am waiting for a cap kit from Just Radios to replace this one. Could this cap be my headache?
::::Also need to verify that the model # i gave was the RCA 56X3?
::::
::::Mitch
::::
:::
:::Go to the "Resources" tab at the top of this page. Scroll down and click on RCA Victor Co.Inc. Scroll down and click on 56X3. Click on the eye. There are 3 choices. Choose the last one- Riders vol. 15-31. That will be the schematic you need.
:::I'd print it out.
:::Terry
:::
::More-
::I notice that there are some notes at the bottom of the service info page. Apparently the position of some leads are critical. I have a feeling that these are mostly concerned with induced hum, but you never know. I'd try and dress the wires as indicated. See if that helps.
::T.
::
:
:Terry,
:
:I checked the voltages on the 12SG7, cathode is 4.8V and plate is 92.5V.
:Whats your thought on the static coming from the C8 cap that i have not replaced yet?
:I will try the dress up of components according to Riders 15-31.
:
:Mitch
:
Warren said that C8 looks like part of the tone circuit. I think he meant C10. I think C8 is there to block any residual DC from going to the coupling cap, (C9) to the output stage. Yes, I'd change it.
Okay, we've established that the oscillator is working, and the detector and audio amp sections are working. Now, that leaves only the RF or IF sections, or you actually need a 100' long wave antenna. We'll leave that, though, as a last resort. My Wellman's Elementary Radio Servicing" suggests that if the plate and cathode voltages are correct, check screen voltage, this should be near the plate voltage. If none, check voltage divider. Next measure voltage from cathode to control grid. This should be the same as cathode to ground.
Next would be a signal gain test to make sure each stage has the proper gain. This should be done with a signal generator and signal tracer, or by the old standby-the buzz test. To do this you take a test probe and, making sure the other end is properly isolated, touch the control grid of each tube. DO NOT TOUCH THE END OF THE PROBE WITH YOUR HAND AND KEEP THE OTHER HAND AWAY FROM THE CHASSIS! You should hear a buzz in the speaker. Start at the output and work backwards. The volume should drop a little in each stage. If you reach a stage where the signal drops significantly, or almost disappears, that is where the problem is. If NONE of these test show any obvious problem, then go to Radio Shack and buy a long wave antenna kit.
Okay- I might be missing something and if so I hope some other member steps up to the plate and makes some suggestion.
Have fun-
Terry

:::::::::Be sure to check the loop antenna connections, and for continuity. The external antenna is a single loop around the primary loop, for a external long wire.
:::::::::
::::::::Warren,
::::::::
::::::::Loop antenna is fine. Resoldered connections. Omic readings are according to schematic. All is in tact, never removed from frame of radio. Can touch antenna coils and receive better signal. Will chase front end gain issues.
::::::::
::::::::Thanks, and please respond to trail.
::::::::
::::::::Mitch
::::::::
:::::::I was looking at the wrong info. The Riders service info on 15-26 suggests a RF amplifier. Oops. Anyway, check the voltages around the 12SG7 converter, especially the cathode, which should be 4.7, also the plate. A low voltage there would indicate a leaky cap that you missed, some problem with the primary of the 1st IF or a change in the value of R1.
:::::::Let us know.
:::::::Terry
:::::::T.
:::::::
::::::
::::::Terry,
::::::
::::::Will check this out tonight and let you know.
::::::
::::::Mitch
::::::
:::::Terry,
:::::
:::::I am about to work on the radio now and i have a question as long as you might be looking at the schematic. I changed all of the paper caps except one, C8. The part list calls for a .0003 MFD, observation of the cap reads .035 MFD 600 Volt. The cap is chipped on one end. I am waiting for a cap kit from Just Radios to replace this one. Could this cap be my headache?
:::::Also need to verify that the model # i gave was the RCA 56X3?
:::::
:::::Mitch
:::::
::::
::::Go to the "Resources" tab at the top of this page. Scroll down and click on RCA Victor Co.Inc. Scroll down and click on 56X3. Click on the eye. There are 3 choices. Choose the last one- Riders vol. 15-31. That will be the schematic you need.
::::I'd print it out.
::::Terry
::::
:::More-
:::I notice that there are some notes at the bottom of the service info page. Apparently the position of some leads are critical. I have a feeling that these are mostly concerned with induced hum, but you never know. I'd try and dress the wires as indicated. See if that helps.
:::T.
:::
::
::Terry,
::
::I checked the voltages on the 12SG7, cathode is 4.8V and plate is 92.5V.
::Whats your thought on the static coming from the C8 cap that i have not replaced yet?
::I will try the dress up of components according to Riders 15-31.
::
::Mitch
::
: Warren said that C8 looks like part of the tone circuit. I think he meant C10. I think C8 is there to block any residual DC from going to the coupling cap, (C9) to the output stage. Yes, I'd change it.
:Okay, we've established that the oscillator is working, and the detector and audio amp sections are working. Now, that leaves only the RF or IF sections, or you actually need a 100' long wave antenna. We'll leave that, though, as a last resort. My Wellman's Elementary Radio Servicing" suggests that if the plate and cathode voltages are correct, check screen voltage, this should be near the plate voltage. If none, check voltage divider. Next measure voltage from cathode to control grid. This should be the same as cathode to ground.
:Next would be a signal gain test to make sure each stage has the proper gain. This should be done with a signal generator and signal tracer, or by the old standby-the buzz test. To do this you take a test probe and, making sure the other end is properly isolated, touch the control grid of each tube. DO NOT TOUCH THE END OF THE PROBE WITH YOUR HAND AND KEEP THE OTHER HAND AWAY FROM THE CHASSIS! You should hear a buzz in the speaker. Start at the output and work backwards. The volume should drop a little in each stage. If you reach a stage where the signal drops significantly, or almost disappears, that is where the problem is. If NONE of these test show any obvious problem, then go to Radio Shack and buy a long wave antenna kit.
:Okay- I might be missing something and if so I hope some other member steps up to the plate and makes some suggestion.
:Have fun-
:Terry
: