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

Hi, i´m Stefan from Germany.

I have just a electronic question to you. I´ve got a few days ago a Korg Polysix with already
done Battery replacement and a new IC31 (74LS08). Now, the programmer works fine, no duplicate
lighting LED´s or something else but the Knobs won´t work anymore. The only which works are
Octave set, waveform, effect mode, tune, bend and volume and the modulators left from te
keyboard. The other knobs with variable resistors won´t work anymore.

So i´ve taken another dead polysix and removed his KLM 369+370 and connected it to the other
one, exact the same Problem. The MG-LED also is flushing but doesn´t recognize any MG-
Frequency setting. So i´ve thought i have to replace IC30 which i´ve done and after it exact
the same problem. Now i´ve taken from the old KLM-367-Board the 8048, still the same.

The Internal variable resistors (offset and so on) on the KLM-367 works but the variable
resistor for "reset" does not working. AFAIK if i tweak him counterwise then normally the
Board must perform a Reset and all led´s should lighting, but he doesn´t do that. On the red
cables are all voltages what the board should get and i also see no destroyed lines.

If i switch the board into "test" mode then the Programmer´s LEDs 4 and 8 Light instead of 1
and 8, even when i try to correct it with the offset and with resistor. I believe it´s because
KLM 369 and 370 won´t work.

I have at the moment -no- Idea what´s the matter. I study the schematics but can´t find any
error on the board-maybe another IC is defective (note: Also the two socked LM13600 were
replaced).

Do you have any Idea what or which IC can be defect. I can guarantee that the two LS7408 are
correctly working.

Thanks for your halp!

Stef