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

I wonder if the DAC is not working correctly?   I think this may be hard to work on without a 'scope.  Maybe you have a friend with one?   In the DAC calibration, you would see the DAC output switching between +5 and -5 as it
measures the Cutoff and Effect intensity pot voltages.   You would also want to check the voltage at the DATA input from the front panel, which feeds to a
comparator on the 367 board.   (In normal operating mode) Again, you would need a scope, as it is scanning a number of different controls rapidly.   Hmm.   I guess if you set all of the front panel controls to the center position, you could see if you get ~0V at this pt, then set them all fully CCW and see if you get -5, then all fully CW and check for +5.   Also if you set them all to center pos, then adjust one CW, a meter should show the average voltage rising.  It should increase to 5V/# of pots scanned if you just change one to full CW.  You could note that value, then increase another one to full CW and you should get twice that much voltage.  That would give you more information about the front panel analog muxing circuitry.

   But a 'scope would be so much better for this sort of thing...
   Good luck.   Where are you located, BTW?

      Bob