1971 Skylark Radio

8/29/2006 12:22:15 PMDave Froehlich

Hello All,
I have replaced all the capacitors I think, could be causing this problem. At a low volume everything sounds very good. But if it's turned up a bit it really distorts. Everything seems to be working as well. All the voltages seem good. It cannot be the speaker because I am using that with a 1964 Studebaker radio, which had another symptom (low volume) but I solved that and it sounds fine throught that speaker. This speaker also worked well with a '65 Chevrolet radio. It had distorted sound but when I replaced the filter capacitors, the sound cleared right up, as do most, with the DS-501 circuit. But not so for the 1971 Skylark radio. The sound is full and clear at a lower volume. There is plenty of bass too. But it distorts when at a reasonable listening level.
Someone from this forum sent me the SAMs photofact for this radio however, now I cannot find it. Sorry about that. Anyway, It seems to be identical to other GM radios, including the Studebaker radio. It just doesn't make any sense to me. Please help if you can.

Thanks,

Dave

8/29/2006 9:32:09 PMMAG

Hi Dave,
You said: "The sound is full and clear at a lower volume. There is plenty of bass too".

Maybe too much bass, with a kind of muffled sound? This is usually due to a leaky section of the filter electrolytic. Try disconnecting the sections one at a time and bridging in known good capacitors.

There are 4 variations of the 1971 AM radio: 2 with DM-28 audio/driver module with either DS-501 or DS-503 output transistor, and 2 with discrete transistors instead of the module and either DS-501 or DS-503.

Have you checked the 3 mfd. 12 volt audio coupling capacitor? I have found these to be open. Also check the 30 mfd. 6 volt AGC cap. Both of these small electrolytic caps are mounted on the printed circuit board. Some of these radios had a fader for a rear speaker or a shorting bar if the fader is not present. The faders can give a lot of trouble too.

I still have your mailing address, let me know if you want a copy of the Delco service literature for your radio. Also let me know the model number.

Meade

:Hello All,
: I have replaced all the capacitors I think, could be causing this problem. At a low volume everything sounds very good. But if it's turned up a bit it really distorts. Everything seems to be working as well. All the voltages seem good. It cannot be the speaker because I am using that with a 1964 Studebaker radio, which had another symptom (low volume) but I solved that and it sounds fine throught that speaker. This speaker also worked well with a '65 Chevrolet radio. It had distorted sound but when I replaced the filter capacitors, the sound cleared right up, as do most, with the DS-501 circuit. But not so for the 1971 Skylark radio. The sound is full and clear at a lower volume. There is plenty of bass too. But it distorts when at a reasonable listening level.
: Someone from this forum sent me the SAMs photofact for this radio however, now I cannot find it. Sorry about that. Anyway, It seems to be identical to other GM radios, including the Studebaker radio. It just doesn't make any sense to me. Please help if you can.
:
:Thanks,
:
:Dave

9/2/2006 5:29:07 PMDave Froehlich

Mag,
I replaced the filter capacitors and tried different ones and it still does that. You were telling me about the tantilum capacitor on the smaller PC board that the volume/tone control is attached to. I'm sorry, I cannot find the service data you sent me. I have no idea where I put it. All that's on that capacitor is a + sign and some code numbers. But I do not see a value on it. I will try replacing that if I know what value it is.

The model number is: 7343514.

Thanks,

Dave
:
:
:
:Hi Dave,
:You said: "The sound is full and clear at a lower volume. There is plenty of bass too".
:
:Maybe too much bass, with a kind of muffled sound? This is usually due to a leaky section of the filter electrolytic. Try disconnecting the sections one at a time and bridging in known good capacitors.
:
:There are 4 variations of the 1971 AM radio: 2 with DM-28 audio/driver module with either DS-501 or DS-503 output transistor, and 2 with discrete transistors instead of the module and either DS-501 or DS-503.
:
:Have you checked the 3 mfd. 12 volt audio coupling capacitor? I have found these to be open. Also check the 30 mfd. 6 volt AGC cap. Both of these small electrolytic caps are mounted on the printed circuit board. Some of these radios had a fader for a rear speaker or a shorting bar if the fader is not present. The faders can give a lot of trouble too.
:
:I still have your mailing address, let me know if you want a copy of the Delco service literature for your radio. Also let me know the model number.
:
:Meade
:
:
::Hello All,
:: I have replaced all the capacitors I think, could be causing this problem. At a low volume everything sounds very good. But if it's turned up a bit it really distorts. Everything seems to be working as well. All the voltages seem good. It cannot be the speaker because I am using that with a 1964 Studebaker radio, which had another symptom (low volume) but I solved that and it sounds fine throught that speaker. This speaker also worked well with a '65 Chevrolet radio. It had distorted sound but when I replaced the filter capacitors, the sound cleared right up, as do most, with the DS-501 circuit. But not so for the 1971 Skylark radio. The sound is full and clear at a lower volume. There is plenty of bass too. But it distorts when at a reasonable listening level.
:: Someone from this forum sent me the SAMs photofact for this radio however, now I cannot find it. Sorry about that. Anyway, It seems to be identical to other GM radios, including the Studebaker radio. It just doesn't make any sense to me. Please help if you can.
::
::Thanks,
::
::Dave

9/3/2006 1:07:32 AMMAG

Dave,
You said "The model number is: 7343514". Did you mean 7313514? As far as I know there is no 7343514.
Information on 7313514 can be found in Sams AR-101(1971 production), and in AR-118(1972 production).

I believe we are talking about 2 different radios here? The information I sent you is for the Buick Special AM/FM model 14AFP1 (probably the same thing as 7313514). My earlier comments in this post were for the AM only radio. However most of the comments still apply (14AFP1 does not have the DM-28 module).

There should be 2 tantalum capacitors on the small audio circuit board, both are 3 mfd. at 10 volts, Delco part number 7312286. One is before the volume control, one after.

Although you probably have already tried this, squirt some contact cleaner into the bias pot and exercise it, then reset it for 1.5 volts DC on the DS-501 collector (case). If it can't be set to 1.5 volts, look for trouble in the audio driver stages. Also, have you ruled out the DS-501?

I can send another copy of the service info for the 14AFP1 if you wish. Let me know.

Meade

:Mag,
: I replaced the filter capacitors and tried different ones and it still does that. You were telling me about the tantilum capacitor on the smaller PC board that the volume/tone control is attached to. I'm sorry, I cannot find the service data you sent me. I have no idea where I put it. All that's on that capacitor is a + sign and some code numbers. But I do not see a value on it. I will try replacing that if I know what value it is.
:
: The model number is: 7343514.
:
:Thanks,
:
:Dave
::
::
::
::Hi Dave,
::You said: "The sound is full and clear at a lower volume. There is plenty of bass too".
::
::Maybe too much bass, with a kind of muffled sound? This is usually due to a leaky section of the filter electrolytic. Try disconnecting the sections one at a time and bridging in known good capacitors.
::
::There are 4 variations of the 1971 AM radio: 2 with DM-28 audio/driver module with either DS-501 or DS-503 output transistor, and 2 with discrete transistors instead of the module and either DS-501 or DS-503.
::
::Have you checked the 3 mfd. 12 volt audio coupling capacitor? I have found these to be open. Also check the 30 mfd. 6 volt AGC cap. Both of these small electrolytic caps are mounted on the printed circuit board. Some of these radios had a fader for a rear speaker or a shorting bar if the fader is not present. The faders can give a lot of trouble too.
::
::I still have your mailing address, let me know if you want a copy of the Delco service literature for your radio. Also let me know the model number.
::
::Meade
::
::
:::Hello All,
::: I have replaced all the capacitors I think, could be causing this problem. At a low volume everything sounds very good. But if it's turned up a bit it really distorts. Everything seems to be working as well. All the voltages seem good. It cannot be the speaker because I am using that with a 1964 Studebaker radio, which had another symptom (low volume) but I solved that and it sounds fine throught that speaker. This speaker also worked well with a '65 Chevrolet radio. It had distorted sound but when I replaced the filter capacitors, the sound cleared right up, as do most, with the DS-501 circuit. But not so for the 1971 Skylark radio. The sound is full and clear at a lower volume. There is plenty of bass too. But it distorts when at a reasonable listening level.
::: Someone from this forum sent me the SAMs photofact for this radio however, now I cannot find it. Sorry about that. Anyway, It seems to be identical to other GM radios, including the Studebaker radio. It just doesn't make any sense to me. Please help if you can.
:::
:::Thanks,
:::
:::Dave

9/4/2006 8:34:09 PMDave Froehlich

Mag,
Yes, it is 7313514, 14AFP1. 3 Mfd is exactly what I'm looking for.
Thanks very much,

Dave
:Dave,
:You said "The model number is: 7343514". Did you mean 7313514? As far as I know there is no 7343514.
:Information on 7313514 can be found in Sams AR-101(1971 production), and in AR-118(1972 production).
:
:I believe we are talking about 2 different radios here? The information I sent you is for the Buick Special AM/FM model 14AFP1 (probably the same thing as 7313514). My earlier comments in this post were for the AM only radio. However most of the comments still apply (14AFP1 does not have the DM-28 module).
:
:There should be 2 tantalum capacitors on the small audio circuit board, both are 3 mfd. at 10 volts, Delco part number 7312286. One is before the volume control, one after.
:
:Although you probably have already tried this, squirt some contact cleaner into the bias pot and exercise it, then reset it for 1.5 volts DC on the DS-501 collector (case). If it can't be set to 1.5 volts, look for trouble in the audio driver stages. Also, have you ruled out the DS-501?
:
:I can send another copy of the service info for the 14AFP1 if you wish. Let me know.
:
:Meade
:
:
:
::Mag,
:: I replaced the filter capacitors and tried different ones and it still does that. You were telling me about the tantilum capacitor on the smaller PC board that the volume/tone control is attached to. I'm sorry, I cannot find the service data you sent me. I have no idea where I put it. All that's on that capacitor is a + sign and some code numbers. But I do not see a value on it. I will try replacing that if I know what value it is.
::
:: The model number is: 7343514.
::
::Thanks,
::
::Dave
:::
:::
:::
:::Hi Dave,
:::You said: "The sound is full and clear at a lower volume. There is plenty of bass too".
:::
:::Maybe too much bass, with a kind of muffled sound? This is usually due to a leaky section of the filter electrolytic. Try disconnecting the sections one at a time and bridging in known good capacitors.
:::
:::There are 4 variations of the 1971 AM radio: 2 with DM-28 audio/driver module with either DS-501 or DS-503 output transistor, and 2 with discrete transistors instead of the module and either DS-501 or DS-503.
:::
:::Have you checked the 3 mfd. 12 volt audio coupling capacitor? I have found these to be open. Also check the 30 mfd. 6 volt AGC cap. Both of these small electrolytic caps are mounted on the printed circuit board. Some of these radios had a fader for a rear speaker or a shorting bar if the fader is not present. The faders can give a lot of trouble too.
:::
:::I still have your mailing address, let me know if you want a copy of the Delco service literature for your radio. Also let me know the model number.
:::
:::Meade
:::
:::
::::Hello All,
:::: I have replaced all the capacitors I think, could be causing this problem. At a low volume everything sounds very good. But if it's turned up a bit it really distorts. Everything seems to be working as well. All the voltages seem good. It cannot be the speaker because I am using that with a 1964 Studebaker radio, which had another symptom (low volume) but I solved that and it sounds fine throught that speaker. This speaker also worked well with a '65 Chevrolet radio. It had distorted sound but when I replaced the filter capacitors, the sound cleared right up, as do most, with the DS-501 circuit. But not so for the 1971 Skylark radio. The sound is full and clear at a lower volume. There is plenty of bass too. But it distorts when at a reasonable listening level.
:::: Someone from this forum sent me the SAMs photofact for this radio however, now I cannot find it. Sorry about that. Anyway, It seems to be identical to other GM radios, including the Studebaker radio. It just doesn't make any sense to me. Please help if you can.
::::
::::Thanks,
::::
::::Dave

9/2/2006 5:35:35 PMDave Froehlich

Mag,
This set had trouble with the fader socket. It was cracked. Maybe the plug-in fader control is also damaged. It seems ok to me but I think I can get a replacement control.
I replaced every electrolytic capacitor, and a paper capacitor. The only capacitor I didn't replace is the tantalum one.

Thanks,

Dave
:
:
:
:Hi Dave,
:You said: "The sound is full and clear at a lower volume. There is plenty of bass too".
:
:Maybe too much bass, with a kind of muffled sound? This is usually due to a leaky section of the filter electrolytic. Try disconnecting the sections one at a time and bridging in known good capacitors.
:
:There are 4 variations of the 1971 AM radio: 2 with DM-28 audio/driver module with either DS-501 or DS-503 output transistor, and 2 with discrete transistors instead of the module and either DS-501 or DS-503.
:
:Have you checked the 3 mfd. 12 volt audio coupling capacitor? I have found these to be open. Also check the 30 mfd. 6 volt AGC cap. Both of these small electrolytic caps are mounted on the printed circuit board. Some of these radios had a fader for a rear speaker or a shorting bar if the fader is not present. The faders can give a lot of trouble too.
:
:I still have your mailing address, let me know if you want a copy of the Delco service literature for your radio. Also let me know the model number.
:
:Meade
:
:
::Hello All,
:: I have replaced all the capacitors I think, could be causing this problem. At a low volume everything sounds very good. But if it's turned up a bit it really distorts. Everything seems to be working as well. All the voltages seem good. It cannot be the speaker because I am using that with a 1964 Studebaker radio, which had another symptom (low volume) but I solved that and it sounds fine throught that speaker. This speaker also worked well with a '65 Chevrolet radio. It had distorted sound but when I replaced the filter capacitors, the sound cleared right up, as do most, with the DS-501 circuit. But not so for the 1971 Skylark radio. The sound is full and clear at a lower volume. There is plenty of bass too. But it distorts when at a reasonable listening level.
:: Someone from this forum sent me the SAMs photofact for this radio however, now I cannot find it. Sorry about that. Anyway, It seems to be identical to other GM radios, including the Studebaker radio. It just doesn't make any sense to me. Please help if you can.
::
::Thanks,
::
::Dave