740 Stock radio problems

The strangest thing started happening with my stock radio (Volvo TD-6141), which also has the graphic equalizer under it (Volvo EQ-611). The system contains 4 total speakers, one on each door. What happened was that both my front door speakers just went out, the rear ones still working, the driver's side rear speaker playing music just faintly, as its been doing as long as I can remember. What's strange about this is that the front driver's side speaker starts working after the car is started, the front passenger's side staying silent. Also, the front speakers used to and occasionally still make a high pitched warbling noise that fades gradually as the radio is on. What could have caused this problem and how can I fix it? Any info helps. Thanks.

Ahh, the fun of restoring 80's consumer electronics.

Haven't any experience with your particular radio (no 7/9 cars in the fleet) but quite a few failures and successes with others of that era without the benefit of service information.

To sum up the failures I blame the way they did double-sided phenolic printed wiring boards then, with actual silver printing rather than etching to form the component side circuits. I get tired of tracing, testing, and bypassing the topside paths.





The successes were always a combination of reflowing cracked solder around the heavier component leads and, of course, cleaning the carbon potentiometer innards of that multi-purpose volume control. Then again in a few years. Never any parts replacements other than tape deck belts, and once, a motor.

In that case, I'll pull out the head unit and clean it all up and check all the circuits making sure there are no breaks. What this doesn't explain is how the driver's door speaker works only when the engine is running. I think what I'll end up doing is replacing the head unit altogether if I can't find the cause of these problems.