The left side sound cut out on the oem 1990 tape/aux head unit. Jiggling the fader control worked for a while to restore full sound, but now the left side is totally dead.
The front/back fade setting works fine.
Treble/Bass seems to be functional.
I've read that you can bypass the fader/potentiometer by replacing it with resistors rated at half resistance of the fader/potentiometer.
I opened up the unit and the fader connections are a bit more complex than I anticipated. Here are the pics:
I think the FUBAR condition is in the 1,2,3 connections.
Checking resistance with all settings in the middle, I get
1-3: 45 ohms
1-2: infinite
2-3: 70 ohms
With the left/right fader turned all the way clockwise, I get
1-3: 45 ohms
1-2: 60 ohms
2-3: 5 ohms
With the left/right fader turned all the way counterclockwise I get
1-3: 45 ohms
1-2: 7 ohms
2-3: 55 ohms
I'm not entirely sure what to make of this, as when the fader is turned full counterclockwise (right volume cutout), I don't get any sound from the left speakers. I don't get any sound from the left speakers in any setting anymore.
I know it's easy enough to put in an aftermarket unit, but this is a quest of curiosity to see if I can rig a fix.
I don't need fade/balance, so I thought perhaps a 20 ohm resistor from 2-1 and 2-3 would bypass the fader and give me full left/right sound again. Please let me know if I'm missing something as circuitry is not exactly my forte.
Thanks!