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Yamaha cr 620, Balance function not working

This receiver may have a simple or complex problem but I am a newbie and require some advise.
The cr 620 right side is very weak, when I turn the balance knob I get varying results of higher or lower volume on right side. The right side has a constant low hum and has much static and distoration when I rotate or jiggle the knob. I get very little sound from the rigth side (alomost none) and it is always more distorted than clear sounding.
The left side seems to work just fine howeve hard to tell if I ma gettin balancce variablilityo left side since it seems as soon as I rotate balance knob left of 12 noon full volume on left side is acheived, volume or sound does not increase as i roate balance knob further to the left.

I have sprayed electronic cotnact cleaner in the rheostat, but no changes (better or worse) were apparent.

I would like to start by replacing the balance rheostat (is it a rheostat and am I using the correct terminology?). I reviewed the specs but could not interpret well enough to identify the balance rheostat part number
Can someone advise me of the part number and where I can order this item?
Also, If I am going down the wrong path and this is clearly not a rehostat problem, can someone advise how I can best begin troubleshooting and\or replacing board components?
Any help is greatly appreciated.

Yamaha cr 620, Balance function not working

From your description, especially with a constant hum, I would look for problems other than the "Potentiometer" or POT

Check if the connections on the board are secure, and that the foil is not broken. (A common problem with these old units.)
You can test this control by removing it and measuring it with an ohm meter.
I believe it is a single gang (3 pins) so you clip your leads to the center pin, and left pin. The ohmage value should go from 0 ohms to its rated value (usually 50K, 100K, or 500K) smoothly. If the ohm value goes to overload or infinite ohms at any time during the travel, the pot is broken. Do this same test using the center pin and right pin, which should give the same results.

The hum and scratching could be caused by DC voltage appearing on the left or right pin of the pot. This can be from a leaky cap, or bad transistor or IC. Hum could also be a result of problems on your output stage.