Repairing a 1979 Pontiac AM-FM 8-track stereo

[SuperDuty]

Hi,

I just got a very cheap '79 AM-FM 8-track stereo unit made by Delco, that came from a '79 Firebird, maybe an early 1980 model (the components are dated from mid-'79).

So the first thing I did is to disassemble it to have a look at the condition. First thing I saw is a broken coil/inductor moving around in the unit.
Also the belt is loose and cracked, not surprising.

I did not see anything else that could be an issue, minor surface rust on some steel parts, and light oxydation on aluminium elements.

Just next to the broken inductor is another identical one, so I tried to desolder it but as soon as I pulled it (gently), it broke as well.

There are no marking on either of them, the only thing I can read is "TRW" on the bottom, one has "5" and the other "30" written below it. They are labeled L1 and L2 on the PCB :



Bottom of the radio mainboard :


Where can I find such components ?

Is there a good source for new belts ?

Thanks !

[stj]

Re: Repairing a 1979 Pontiac AM-FM 8-track stereo

looks like tuning coils - probably for the AM radio.

you should have left the radio and took the car instead!

[SuperDuty]

Re: Repairing a 1979 Pontiac AM-FM 8-track stereo

I'm restoring a '74 Firebird, I want my interior to look all factory original except it won't be...at all :p It's a mix a parts from all the 2nd generation.
Also I've always been curious about 8-tracks, these have never been popular around here so it's an oddity for me and I want to make it work !

[midibob]

Re: Repairing a 1979 Pontiac AM-FM 8-track stereo

Hi,
I've found this which might help you a little although there is no schematic.
http://www.corvetteforum.com/forums/...gm-2700-a.html

Good luck
Bob

[eccerr0r]

Re: Repairing a 1979 Pontiac AM-FM 8-track stereo

Unfortunately these IF transformers are specific to the design, and are tuned to the IFs...
This will probably be difficult to replace, probably have to trace the circuit and see what inductor is needed to make a bandpass at the IF (need to look if it's on the AM or FM circuit) and wind your own transformer.

I'd probably look into another radio if you want it to work else you'd have to gut the radio and use another circuit in there...

[SuperDuty]

Re: Repairing a 1979 Pontiac AM-FM 8-track stereo

Thanks for the replies. by looking closely at the board, it looks to be on the FM circuit which is the useful one (AM is useless here, if it were on this circuit I wouldn't care too much).
Do you think these components can be repaired ? They look very simple, but the wire is tiny.

I've just bought an AM/FM cassette unit, by the looks of the knobs it would be a Buick version of the same period, but it should be very similar internally. Maybe the IF transformers are the same on the radio board and I could either swap them or identify them. But it looks to be in good condition so it might be a bad idea to use it for parts.

I'll try to find a cheap AM/FM delco unit, someone around here must have one of those.

[SuperDuty]

Re: Repairing a 1979 Pontiac AM-FM 8-track stereo

I've just put it back together and made some tests, and indeed, the FM doesn't work. No sound comes out. AM works fine, though it's completely useless since it's just gibberish and some foreign stations with no music.

I've found the wires that send the signal from the radio board to the amp, to add an auxiliary input. It will be an easy mod.

As for the 8 track, I don't have any, but I turned the switch on and it seems to work properly. The loose and cracked belt didn't hold for long.