1970s AM/FM/8 track problems

[chirt1976]

Hello everyone. I'm a recent owner of a 1976 Seville that is finally roadworthy after several decades of sitting. I've been sorting out mechanical issues and doing preventative maintenance, but the radio has been giving me all kinds of problems. The best way I can explain it is that the radio seems to be having some sort of grounding issue.

The 8 track seems to function mostly fine, although sometimes the front passenger speaker doesn't want to play sound. The same speaker acts up sometimes during FM mode also, but usually it wakes up after a few minutes.

FM radio is very finicky. When the radio is power on, it always make the "pop/thump" sound like it's supposed to. However, often times the speakers produce very little sound. On full volume, you might faintly hear music if you're in a quiet area. However, sometimes tapping on the volume stalk (I have the knobs removed for this troubleshooting) will often bring the speakers to life and it will play at a normal volume. The best way to "wake up" the FM stereo when it produces no sound is to tighten or loosen the hex nuts on the volume and tuning stalks. Once the radio is happy with the position of the hex nuts, it will play music normally until some harsh vibration from driving will upset the FM stereo, and then I have to fiddle with everything to get working again.

The AM function of radio seems totally dead. I don't care for AM radio, so this doesn't really bother me at all.

The radio itself is stock, but the previous owner made his own connector between the back of the radio to the antenna cord. I've purchased some aftermarket connectors and it seems like I've remedied that issue. The power antenna is original and raises and lowers very reluctantly, so I'm planning on having that shipped off to be rebuilt.

Electronics are not my forte, but do you folks think that my issue is with the radio itself, the antenna, or something else entirely? I've just been scratching my head so long that any other opinions or troubleshooting tips would be greatly appreciated!

[Big Fins]

All the grounds are jumping out at me. If not the radio itself, but the dash and speaker grounds. Refresh them all. Be sure there is no painted area or corrosion between the body and the wire connector.

[76Caddy]

It's the radio, more specifically the on/off, volume shaft.  Every '76 I own/owned had to be repaired.  All had the same issue you described.  The radios with the 8-track option use the on/off, volume knob to change channels and to eject the cartridge and the pushing and pulling of the knob over time causes problems.  Before the repairs, you could turn the radio on, and if you didn't hear anything, pull or push the volume knob and it would start working.

Hope this helps.

Tim   

[Big Fins]

I'm gonna remember that.

Every bump I hit creates a bunch of static anyway. I figure to put a bluetooth speaker on the back seat and just run the music through the phone. Where I am, the radio is pretty much useless anyway.

[chirt1976]

It's the radio, more specifically the on/off, volume shaft.  Every '76 I own/owned had to be repaired.  All had the same issue you described.  The radios with the 8-track option use the on/off, volume knob to change channels and to eject the cartridge and the pushing and pulling of the knob over time causes problems.  Before the repairs, you could turn the radio on, and if you didn't hear anything, pull or push the volume knob and it would start working.

Hope this helps.

Tim   

Thanks, Tim, that definitely makes sense to me. There is a ton of movement on that knob, and I could see how that would lead to issues after so many years. Is that a repair that I might be able to do myself, such as cleaning and/or soldering? I'd appreciate any advice you can give me. Thanks again!

-Mike

[76Caddy]

Thanks, Tim, that definitely makes sense to me. There is a ton of movement on that knob, and I could see how that would lead to issues after so many years. Is that a repair that I might be able to do myself, such as cleaning and/or soldering? I'd appreciate any advice you can give me. Thanks again!

-Mike

There was a shop in town that repaired TVs and radios and I would take them there.  He is the one who told me that the on/off knob was causing the issue.

Tim