This is not a superhet receiver, so there is no IF. This is a regenerative set. The first two tubes are RF amps, followed by a regenerative detector, and then two audio stages.
What are you using for a power supply? It would be unusual to get a hum from a DC-powered radio. What about antenna, ground, and speaker - tell us about those. When you say there is a cap across the "two negative poles," I'm not sure what you mean. Can you pinpoint where it is on the schematic?
Disconnect the radio from whatever power sources you're using, and check the two audio xfmrs for continuity (primary and secondary windings) with an ohmeter. The primaries should read a few hundred ohms, and the secondaries about 1K.
Connect only the A+ and A- and see if all the tubes light up.
After you've done those things, check back here for the next steps to take. By the way, C+ connects to A-, but you're not ready for that yet.
To set your mind at ease, this is a very simple radio and there can't be anything wrong that can't be fixed.
:I have been working on a Crosley battery radio. I get nothing but a loud hum, no signal, and the volume doesn't respond. The grid detector circuit is ok. The only other parts are two transformers. One is supplied +45 which I believe to be the IF. The other is supplied by +90 which I believe is audio. The two are connected by what I believe to be a cap (real old) across the neg poles and the -A supply.The schematic doesn't show any values, and doesn't even show the cap. I don't know how to check transformers. The other thing is the connectors on the radio show +C -A when C is connected I get no sound. When not connected I get sound with hum. The schematic doesn't show a +C connection at all. I'm at my wits end and I am determined to get this thing working Please Help!
:Bill
OK. Power supply is from AES and works fine. The tubes all light up. I checked the transformers and one is open on the primary and secondary, the other is open on the primary. When C+ is connected the buzz /hum goes away.. but nothing is heard from speaker. The speaker is an 8 ohm with a 2500 ohm - 8 ohm transformer. I also checked it with a high impedence headphone driver. They both sound the same. I am using four 201a's and one type 30 as a sub. It should have 2v on the filament but seems to be doing ok with 5v. The mystery cap/whatever is connected to A- and the casing of the two transformers. It is rectangular about 1"x1 1/2" with no markings. It isn't on the schematic. I use a long wire aerial and an earth ground.
Bill
The first step is to fix the two audio xfmrs. Both seem to be shot.
If these are like other Crosley audio xfmrs I've encountered, they are in a black case that can be taken apart easily with four nuts and bolts. Is this yours?
If so, you can replace the windings with RadioDaze cat. # HX124C. AES has an equivalent item.
You need to get another '01A tube. Buy a used one.
I can't explain your "mystery" component. It doesn't seem to belong.
::Bill, we need to back up here and work on some basics. Here's your schematic: http://www.nostalgiaair.org/PagesByModel/694/M0039694.pdf
::
::This is not a superhet receiver, so there is no IF. This is a regenerative set. The first two tubes are RF amps, followed by a regenerative detector, and then two audio stages.
::
::What are you using for a power supply? It would be unusual to get a hum from a DC-powered radio. What about antenna, ground, and speaker - tell us about those. When you say there is a cap across the "two negative poles," I'm not sure what you mean. Can you pinpoint where it is on the schematic?
::
::Disconnect the radio from whatever power sources you're using, and check the two audio xfmrs for continuity (primary and secondary windings) with an ohmeter. The primaries should read a few hundred ohms, and the secondaries about 1K.
::
::Connect only the A+ and A- and see if all the tubes light up.
::
::After you've done those things, check back here for the next steps to take. By the way, C+ connects to A-, but you're not ready for that yet.
::
::To set your mind at ease, this is a very simple radio and there can't be anything wrong that can't be fixed.
::
::
:::I have been working on a Crosley battery radio. I get nothing but a loud hum, no signal, and the volume doesn't respond. The grid detector circuit is ok. The only other parts are two transformers. One is supplied +45 which I believe to be the IF. The other is supplied by +90 which I believe is audio. The two are connected by what I believe to be a cap (real old) across the neg poles and the -A supply.The schematic doesn't show any values, and doesn't even show the cap. I don't know how to check transformers. The other thing is the connectors on the radio show +C -A when C is connected I get no sound. When not connected I get sound with hum. The schematic doesn't show a +C connection at all. I'm at my wits end and I am determined to get this thing working Please Help!
:::Bill
:
:
:
:
:OK. Power supply is from AES and works fine. The tubes all light up. I checked the transformers and one is open on the primary and secondary, the other is open on the primary. When C+ is connected the buzz /hum goes away.. but nothing is heard from speaker. The speaker is an 8 ohm with a 2500 ohm - 8 ohm transformer. I also checked it with a high impedence headphone driver. They both sound the same. I am using four 201a's and one type 30 as a sub. It should have 2v on the filament but seems to be doing ok with 5v. The mystery cap/whatever is connected to A- and the casing of the two transformers. It is rectangular about 1"x1 1/2" with no markings. It isn't on the schematic. I use a long wire aerial and an earth ground.
:
:Bill
If you have the same filament voltage on a 30 and 201A its's not high enough. A 30 will burn out with 5 volts. A 201A will be lit with less than 5 volts but may not have enough emission to operate. Measure filament voltage at tube pins.
Some early radios had caps bypassing batteries. Exact value of these caps aren't critical. Use 1 mf if you have one. Don't understand why a cap was connected from A- to case of transformers unless the case was also grounded?
C+ connects to A-.
Norm
::Bill, we need to back up here and work on some basics. Here's your schematic: http://www.nostalgiaair.org/PagesByModel/694/M0039694.pdf
::
::This is not a superhet receiver, so there is no IF. This is a regenerative set. The first two tubes are RF amps, followed by a regenerative detector, and then two audio stages.
::
::What are you using for a power supply? It would be unusual to get a hum from a DC-powered radio. What about antenna, ground, and speaker - tell us about those. When you say there is a cap across the "two negative poles," I'm not sure what you mean. Can you pinpoint where it is on the schematic?
::
::Disconnect the radio from whatever power sources you're using, and check the two audio xfmrs for continuity (primary and secondary windings) with an ohmeter. The primaries should read a few hundred ohms, and the secondaries about 1K.
::
::Connect only the A+ and A- and see if all the tubes light up.
::
::After you've done those things, check back here for the next steps to take. By the way, C+ connects to A-, but you're not ready for that yet.
::
::To set your mind at ease, this is a very simple radio and there can't be anything wrong that can't be fixed.
::
::
:::I have been working on a Crosley battery radio. I get nothing but a loud hum, no signal, and the volume doesn't respond. The grid detector circuit is ok. The only other parts are two transformers. One is supplied +45 which I believe to be the IF. The other is supplied by +90 which I believe is audio. The two are connected by what I believe to be a cap (real old) across the neg poles and the -A supply.The schematic doesn't show any values, and doesn't even show the cap. I don't know how to check transformers. The other thing is the connectors on the radio show +C -A when C is connected I get no sound. When not connected I get sound with hum. The schematic doesn't show a +C connection at all. I'm at my wits end and I am determined to get this thing working Please Help!
:::Bill
:
:
:
:
:OK. Power supply is from AES and works fine. The tubes all light up. I checked the transformers and one is open on the primary and secondary, the other is open on the primary. When C+ is connected the buzz /hum goes away.. but nothing is heard from speaker. The speaker is an 8 ohm with a 2500 ohm - 8 ohm transformer. I also checked it with a high impedence headphone driver. They both sound the same. I am using four 201a's and one type 30 as a sub. It should have 2v on the filament but seems to be doing ok with 5v. The mystery cap/whatever is connected to A- and the casing of the two transformers. It is rectangular about 1"x1 1/2" with no markings. It isn't on the schematic. I use a long wire aerial and an earth ground.
:
:Bill
Hi,
I replaced both xfrmrs and it works...Yeah! The only other trouble is it has very low volume, but I will leave that issue until I can replacee the 30 sub with a 01a. One the secondary of the xfrmrs there are 3 wires. Two green and a black. I hooked up the greens and the radio works.. where do the black ones go? I really appreciate the help everyone has given me and I'm looking forward to getting this to sound like new.
Thanx
Bill
Just tape the black wire. It's a center tap between the two green ones. Not needed unless the circuit is push pull.
Norm
::Hi
::
:: If you have the same filament voltage on a 30 and 201A its's not high enough. A 30 will burn out with 5 volts. A 201A will be lit with less than 5 volts but may not have enough emission to operate. Measure filament voltage at tube pins.
::
:: Some early radios had caps bypassing batteries. Exact value of these caps aren't critical. Use 1 mf if you have one. Don't understand why a cap was connected from A- to case of transformers unless the case was also grounded?
::
:: C+ connects to A-.
::
::Norm
::
::::Bill, we need to back up here and work on some basics. Here's your schematic: http://www.nostalgiaair.org/PagesByModel/694/M0039694.pdf
::::
::::This is not a superhet receiver, so there is no IF. This is a regenerative set. The first two tubes are RF amps, followed by a regenerative detector, and then two audio stages.
::::
::::What are you using for a power supply? It would be unusual to get a hum from a DC-powered radio. What about antenna, ground, and speaker - tell us about those. When you say there is a cap across the "two negative poles," I'm not sure what you mean. Can you pinpoint where it is on the schematic?
::::
::::Disconnect the radio from whatever power sources you're using, and check the two audio xfmrs for continuity (primary and secondary windings) with an ohmeter. The primaries should read a few hundred ohms, and the secondaries about 1K.
::::
::::Connect only the A+ and A- and see if all the tubes light up.
::::
::::After you've done those things, check back here for the next steps to take. By the way, C+ connects to A-, but you're not ready for that yet.
::::
::::To set your mind at ease, this is a very simple radio and there can't be anything wrong that can't be fixed.
::::
::::
:::::I have been working on a Crosley battery radio. I get nothing but a loud hum, no signal, and the volume doesn't respond. The grid detector circuit is ok. The only other parts are two transformers. One is supplied +45 which I believe to be the IF. The other is supplied by +90 which I believe is audio. The two are connected by what I believe to be a cap (real old) across the neg poles and the -A supply.The schematic doesn't show any values, and doesn't even show the cap. I don't know how to check transformers. The other thing is the connectors on the radio show +C -A when C is connected I get no sound. When not connected I get sound with hum. The schematic doesn't show a +C connection at all. I'm at my wits end and I am determined to get this thing working Please Help!
:::::Bill
:::
:::
:::
:::
:::OK. Power supply is from AES and works fine. The tubes all light up. I checked the transformers and one is open on the primary and secondary, the other is open on the primary. When C+ is connected the buzz /hum goes away.. but nothing is heard from speaker. The speaker is an 8 ohm with a 2500 ohm - 8 ohm transformer. I also checked it with a high impedence headphone driver. They both sound the same. I am using four 201a's and one type 30 as a sub. It should have 2v on the filament but seems to be doing ok with 5v. The mystery cap/whatever is connected to A- and the casing of the two transformers. It is rectangular about 1"x1 1/2" with no markings. It isn't on the schematic. I use a long wire aerial and an earth ground.
:::
:::Bill
:
:
:Hi,
:
:I replaced both xfrmrs and it works...Yeah! The only other trouble is it has very low volume, but I will leave that issue until I can replacee the 30 sub with a 01a. One the secondary of the xfrmrs there are 3 wires. Two green and a black. I hooked up the greens and the radio works.. where do the black ones go? I really appreciate the help everyone has given me and I'm looking forward to getting this to sound like new.
:Thanx
:Bill
If so, just tape up the end of the extra wire and leave it unconnected. For neatness, you can trim the length.
::
::I replaced both xfrmrs and it works...Yeah! The only other trouble is it has very low volume, but I will leave that issue until I can replacee the 30 sub with a 01a. One the secondary of the xfrmrs there are 3 wires. Two green and a black. I hooked up the greens and the radio works.. where do the black ones go? I really appreciate the help everyone has given me and I'm looking forward to getting this to sound like new.
::Thanx
::Bill