Cr-640 balance control cleaning or replacement

SRK

New Member
It's quite scratchy and Deoxit has not completely fixed the problem. The service manual does not give sufficient detail regarding how to remove the balance control to clean it or replace it. It does describe how to get the faceplate off. Once I do that, how do I remove the balance control, and then, any suggestions about how I repair the balance control, if that's even possible?
 
The balance knob should just pull off, check for any hex screw like what's
on the tuning knob, but unlikely to be on the smaller balance.

Deoxit is the best solution, I haven't had any success with disassembly
followed by deep cleaning, easier to find a replacement. The balance pot
is a 20k dual gang linear taper, could also use a 50k if 20k hard to find.
The "problem" will be to get the right pinout, shaft length, type,,,

Normally, the balance is set and forget, is it still scratchy/noisy once
set? May be something like a noisy transistor?
 
It's become less so, but I can't say with confidence that it will remain adequate. I don't know how to get the balance pot off the circuit board. Pry it off with a screw driver?
 
I don't know how to get the balance pot off the circuit board. Pry it off with a screw driver?
Please don't use any significant force, this is an indication that you are doing something wrong.

The balance pot will have pins that are soldered to the board, these should be unsoldered, preferrably using a solder pump, so the pins are free to move.
There will also be a locking nut on the shaft, needed to remove the face plate.

Normally, the balance is set and forget, is it still scratchy/noisy once
set? May be something like a noisy transistor?
What make you think there is a problem with the balance pot, no big deal that there is some scratchy noise when you are adjusting it, is there still noise once
balance is set?
 
Before repeated applications of Deoxit to the balance pot, I would lose much of the volume in the right channel, which came in and out as I turned the balance, and I would try to find a sweet spot where I would get both channels. The audio itself was often scratchy. Now the volume is much more stable and I can actually hear the audio in stereo. It is not perfect, however. I suspect there might be damage Deoxit won’t fix. Thanks for the info on removing the pot. I’m not sure I want to tackle that task, though.
 
yep, agree with pete, the balance pot is not used as much, so it's unlikely to be worn. Yes pots do fail, most likely volume and tone control.
Probably just a build up of gunk that needs to be cleaned up. Liberal spray of deoxit then work/rotate the balance 20-30-?? times then
another spray and work...
 
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