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Balance control problem on Panasonic SG-999

Jimkarl

Aug 23, 2014
43
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Aug 23, 2014
Messages
43
Have a vintage Panasonic SG-999 integrated stereo, pop up turntable experiencing a strange balance control problem. On one channel, the balance control works fine, meaning if you start center and go to one end it attenuates and fades the signal on that channel down to zero. On the other channel, the control has no effect. It is always on, regardless of the balance control setting. I disassembled and removed the balance pot (R4 on the schematic, 100K with three terminals). Was certain that had to be the problem but using a resistance meter, center pin to end pin(s), it seems to work fine. Reads about 61K to zero as you sweep the control, on both pin combinations. So if the pot is good, there must be something in the circuit bypassing the signal through, ala short someplace, but only in the one direction. Where in the signal path should I be looking? Link to a portion of the schematic is here:
http://home.comcast.net/~jimkarl/Pan...schematic1.jpg

Both channels sound fine and equal volume-wise but this balance control circuit isn't working properly.
 

Gryd3

Jun 25, 2014
4,098
Joined
Jun 25, 2014
Messages
4,098
Perhaps a bad connection or broken trace.
I don't see a reason that would stop working otherwise.
Have you tested the connection on the board from where the potentiometer used to be?
 

Jimkarl

Aug 23, 2014
43
Joined
Aug 23, 2014
Messages
43
Perhaps a bad connection or broken trace.
I don't see a reason that would stop working otherwise.
Have you tested the connection on the board from where the potentiometer used to be?


It was a broken trace on the circuit board. Problem solved! Thanks!
 
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