Korg Poly-61 Master tuning

#1

Hey All, I’ve got a Korg Poly-61 that seems to have the master turning off by about 3 half steps. All oscillators seem to be in tune with each other. I know they are DCO controlled. Any thoughts on where I should look first?

#2

Figured out that there is a variable resister on the master tune board that you can tweak to adjust the tune of the oscillators. I have to turn it all the way down. So there is probably something out of tolerance on the board.