Vintage Synth Repair

Hello there,

I got my Prophet 600 worked on, but there's one problem that still
exists.  One of the voices' levels is lower than the other 11.  (6
voices - 2 osc per voice)  I can isolate which voice it is.

The person who worked on it advised me to attach a trim pot between
one of the chips' pins and ground.  I'm guessing that the chip would
probably be the "bad" VCO out of the twelve 3340 VCOs.

But first, would this fix the problem, and I sort of misplaced the
instructions that the guy gave me a while back...

So basically, I'm asking for any advice for this.  Is the chip in
question one of the VCOs, and how to modify the volume of it?

I have a few jpg schematics if anyone would care to see them...

Thanks all,

Darren Wexler