# Trying to bypass OEM radio fader, need electrical Gurus!



## afterthisnap (Jul 8, 2012)

Hi. I've been scouring the internet for solutions and I was hoping you guys could help. 

The left side sound died out on the oem subaru 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 2 20 ohm resistors 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.

Edit:
Apparently I don't know how to use a multimeter...
All these values were taken at a 10x setting. At 1000x I get different values but they are relatively the same. 
Also, I get different values if I test the same connections but switch the black/red probe of the multimeter.


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