Discussion about the Korg PolySix synthesizer

Am 01.03.2018 um 15:20 schrieb jimpster@me.com [PolySix]:
> So, I'm still none the wiser with the clone board. Filter is always 
> modulating no matter where I set the MG switch.

Check the pins 1, 11, and 12 of IC29 while changing the switch 
positions. They should change from 0 to 5V when the switch changes its 
position.

If No: check whether the switch itself with a scope, In two of its 
positions it should read the signal of CPU ports P12 and P11.
 ���������� Possibly missing P11/12 signal or dirty in the switch

If Yes:

check whether the signal of thos three pins reaches the LM339 at pins 9, 
11, and 5

If no: cold solder joint or pcb trace broken

If yes:

check whether the pis 14,13, and 2 change with changing the switch?

If No: do pins 8,10,4 read 2,5V?

 �������� If no: cold solder joint or pcb trace broken

 �������� If Yes: -> LM339 dead

If Yes:

Check whther the signals reach pins 5,13,12 of IC 1 (4066)

If no: cold solder joint or pcb trace broken

If Yes: 4066 broken.





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