Archive of the former Yahoo!Groups mailing list: Discussion about the Korg PolySix synthesizer

IIRC the pots run on a +/-5v signal, which is multiplexed through IC1 & 2 (14051) to a data line. The control signal turns up again at the output pins of IC18 & IC19 on the KLM-367. Anywhere in that chain may be the problem.
In my case, the KLM-370 had corroded so control signals were not getting through. A lot of repairing traces had to be done.

Your first step would be to check the voltage swings between +/-5v going in to IC1 on pin 14.
To check it is on the data line, you'll need an oscilloscope.
Then check pin 14 on IC18 on the KML-367, as it should be the same as pin 14 on IC1

Anthony,