Discussion about the Korg PolySix synthesizer

Possibly the oscillator was not running when it didn't work.
Different chips are a little different in that area, as it's really an 
analog function, so component tolerances can make a difference.
Just an idea...

I wonder if the +5V is adjusted the same in your unit and the other one.
If it's a little lower, that could affect the oscillator start-up as well.

Bob