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Old 04-27-2016, 08:10 PM
Captainclock Captainclock is offline
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2 AM/FM Pocket Transistor Radios from the early 1980s having issues

Hello everyone, I have recently received from an older lady at church a couple of AM/FM Pocket Transistor Radios from about the early 1980s one is a GE Model 7-2582G and the other one has no model number but has the designation of Imperial BY SUPERSCOPE on the front of the case. Anyways I'm not too sure what the lady did to these radios if anything at all but both of these radios have the same exact issue and that is that they both have extremely distorted audio, its so badly distorted that the audio actually cuts in and out sometimes to the point that nothing can be heard at times. I'm just curious as to what might be causing these two completely different branded radios to have the same the same distorted audio issue.

Any help would be appreciated.

Thanks,

Levi

Last edited by Captainclock; 04-27-2016 at 09:31 PM.
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Old 04-27-2016, 10:42 PM
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Electronic M Electronic M is offline
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Caps, and sometimes bad resistors....If they are push-pull audio and one of the output transistors is bad that that can sound bad too. Alignment could also be an issue, but unlikely if in both bands.
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Old 04-28-2016, 10:00 AM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Captainclock View Post
Hello everyone, I have recently received from an older lady at church a couple of AM/FM Pocket Transistor Radios from about the early 1980s one is a GE Model 7-2582G and the other one has no model number but has the designation of Imperial BY SUPERSCOPE on the front of the case. Anyways I'm not too sure what the lady did to these radios if anything at all but both of these radios have the same exact issue and that is that they both have extremely distorted audio, its so badly distorted that the audio actually cuts in and out sometimes to the point that nothing can be heard at times. I'm just curious as to what might be causing these two completely different branded radios to have the same the same distorted audio issue.

Any help would be appreciated.

Thanks,

Levi
The GE probably has the entire radio-on-a-chip design, like the Superadios.
The other one is probably a more conventional design. My vote would go for dried out electrolytics.
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Old 04-28-2016, 11:40 AM
Captainclock Captainclock is offline
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Originally Posted by dieseljeep View Post
The GE probably has the entire radio-on-a-chip design, like the Superadios.
The other one is probably a more conventional design. My vote would go for dried out electrolytics.
Well the GE uses 4 electrolytics so it should be fairly straight forward to replace them, the other one however is got 8 electrolytics and is kind of a complicated design, I think you might be right about the GE being designed like a Superadio as far as having the entire radio on a chip design because I saw a small chip inside the GE radio that was within the tuner section of the radio, and it seemed to be fairly sensitive when you could hear something on it. I know Superscope was a fairly high end manufacturer back in the day from what I read so the Superscope radio should be a fairly good performer as well once its repaired.

UPDATE: I replaced the electrolytics in the GE Radio and it still has garbled and distorted audio so I'm not quite sure what to do next, I'm hoping its not one of the output transistors because if it is then its probably not going to be worth my time to repair it because those output transistors are quite expensive.

Last edited by Captainclock; 04-28-2016 at 05:58 PM.
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  #5  
Old 04-28-2016, 11:45 AM
Captainclock Captainclock is offline
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Originally Posted by Electronic M View Post
Caps, and sometimes bad resistors....If they are push-pull audio and one of the output transistors is bad that that can sound bad too. Alignment could also be an issue, but unlikely if in both bands.
The distortion is in both bands so its unlikely to be an alignment issue, especially in both radios, my vote is dried electrolytics because they both are from the same time period, although that doesn't explain why these two radios are having issues but not my old Panasonic and Zenith AM/FM transistor radios (which are both from the 1970s).
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Old 04-29-2016, 07:49 AM
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zeno zeno is offline
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Speakers are rubbing & sticking. Plug in an ear phone to test.**

** Tech Tip. Sometimes on radios & cheap stereos with
distortion plugging in headphones make it sound OK BUT
the outputs are bad. Its caused by the decreased load on
the amp. The best test is remove speaker & sub a known
good on.

73 Zeno
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Old 04-29-2016, 08:15 AM
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maxhifi maxhifi is offline
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Just a wild guess, if they both are misbehaving, are you using the same 9V battery in both of them?
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Old 04-29-2016, 10:31 AM
Captainclock Captainclock is offline
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Just a wild guess, if they both are misbehaving, are you using the same 9V battery in both of them?
Yes I was using the same 9V Battery and I did end up subbing a known good battery and it turned out it was the battery causing the problem, turns out the battery I was using was bad so I subbed with a known good 9V battery that was only ever used for battery backup on clock radios and sure enough the radio worked fine! Go figure...
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Old 04-29-2016, 04:00 PM
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zeno zeno is offline
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Quote:
Originally Posted by Captainclock View Post
Yes I was using the same 9V Battery and I did end up subbing a known good battery and it turned out it was the battery causing the problem, turns out the battery I was using was bad so I subbed with a known good 9V battery that was only ever used for battery backup on clock radios and sure enough the radio worked fine! Go figure...
LOL I thought I was pinning it down with the simple answer ( always the best ). Advice holds true for the future anyhows !

BTW weak batteries show up on FM first with distortion & drifting
due to the greater load on circuits.

BTW #2 Superscope was a Sony product, mostly small stuff
like radios, tape etc & built better than average.

73 Zeno
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Old 04-30-2016, 02:34 PM
Captainclock Captainclock is offline
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Quote:
Originally Posted by zeno View Post
LOL I thought I was pinning it down with the simple answer ( always the best ). Advice holds true for the future anyhows !

BTW weak batteries show up on FM first with distortion & drifting
due to the greater load on circuits.

BTW #2 Superscope was a Sony product, mostly small stuff
like radios, tape etc & built better than average.

73 Zeno
Thanks for the info, and yes the GE now that I got it working is pretty sensitive and pulls in lots of stations on the FM and AM.
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