Revox A77MK4 volume and balance issue

[WBCarson]

I bought this player. VERY good condition, been serviced, have the slips.
While playing a tape when i turn the volume knob to zero the left speaker continues to play.
Turning the volume up does increase the volume but i dont get the full stereo in the Left until it is maxed out.
Turning the Balance still favors the left speaker. Turning Balance all the way to the right i still hear the Left playing. All Rheostats were De-oxed by the tech before i bought it.
I did get the volume to silent once, only after rapidly turning it up and down.
Where to start?

Thanks

 

[jlb2]

I'd say it is very probably caused by the lower leg of P301 (cf. the switch board schematic in the A77 service manual) not making contact to ground,either externally because of a broken wire or a cold solder joint, or internally because either the cleaning was not effective enough or the pot itself is defective. Your last sentence, about it working again after fast rotation, makes me think it's more probably one of the latter two options. You need to clean it again with a good contact cleaner, and change it if it still doesn't work. These pots are specific to the A77, but fortunately they are easy to find.

Or another possibility, which can probably save you some hassle if it has been serviced recently and you have the invoice, would be to send it back to for repair under warranty.