1965 GM radio help needed

Discussion in 'General Electronics Chat' started by David F., Nov 20, 2013.

  1. David F.

    Thread Starter New Member

    Nov 20, 2013
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    Don't know if you guys can help me. I have a radio out of a 1965 Corvair and I was trying to test it, either I hooked it up wrong or it is no good. I get a high pitched squeal when I turn it on and try an tune in a station.
    I have it connected to a 8 ohm speaker, with the two green with black stripe wires going to the speaker and the black with yellow stripe going to the hot + battery, with the neg. to the radio chassis.
    I tried finding a 1965 GM radio wiring diagram on the NET, but couldn't locate any.
    If anyone has a diagram or can tell me if this is connected right, I would appreciate it.
    Picture of rear of radio below.



    David
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    This was a time that the 12v tubes (valves) were coming in just prior to the transistor versions.
    Which version is it? the high voltage tubes had a vibrator.
    One of the weak points around this time was the decoupling caps, the wax coated ones.
    Max.
     
  4. David F.

    Thread Starter New Member

    Nov 20, 2013
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    Don't know much about radio electronics, I don't see any tubes. Took the cover off and took two pictures, does this help?

    David
     
  5. MaxHeadRoom

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    Jul 18, 2013
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    I guess you rigged up an antenna? Can you hear any stations in the back ground?
    Max.
     
  6. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Check local library, it might have some books/manuals.
     
  7. David F.

    Thread Starter New Member

    Nov 20, 2013
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    Yes I have an antenna, no stations, just a varying hi pitch squeal.
    Checked the local library, their wiring diagrams, like the ones on the NET, don't show the radio.
    David
     
  8. shteii01

    AAC Fanatic!

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    How many speakers are supposed to be connected to the unit? 2?
     
  9. gnuuser

    New Member

    Jan 17, 2013
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    you had it hooked up correctly but this is an am radio
    if there are flourescent lights nearby you will get a lot of noise from them.
    but it would usually be a loud hum or buzzing.
    a high pitched noise could be a failed transistor. or a shorted trimmer or tuning capacitor
    this is a transistor radio
     
  10. David F.

    Thread Starter New Member

    Nov 20, 2013
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    OK, Thanks. I have tested Ford radios in the same location, and they worked OK. There is a neon light, will try the radio outside, when the rain stops.
    David
     
  11. #12

    Expert

    Nov 30, 2010
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    AM superhetrodyne with almost 50 years of dirt and humidity in the coils.:(
    Getting these back into serviceable condition is an art unto itself.
    The tricks of this trade are numerous.
    Gotta go with Bertus. You belong on a Vintage Radio site.
     
  12. David F.

    Thread Starter New Member

    Nov 20, 2013
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    I am going to post there, but it sounds like the radio is bad.

    David
     
  13. MaxHeadRoom

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    I managed a TV & Car Radio service depot for a couple of years back in the 70's and the CR techs would replace the caps, regardless as a matter of course when one came to the bench.
    IIRC that included the electrolytic's.
    Max.
     
  14. #12

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    While you're doing, "as a matter of course", any carbon resistor in the 100k and up range will be a higher value than it was designed for.
     
  15. David F.

    Thread Starter New Member

    Nov 20, 2013
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    Thanks for the help. I shot the radio with electrical cleaner and got the connections right, and now it works. A Miracle :)

    David
     
  16. MaxHeadRoom

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    Jul 18, 2013
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    That Always helps!!. :cool:
    Max.
     
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