Discussion about the Korg PolySix synthesizer

So yesterday I took out the KLM-367 to examine it more closely. It's 
easy to see that the whole board has had a serious cleaning at one 
point (first battery replacement), as all trimmer pots and the test 
switch look like they have been desoldered and soldered back in.
 CMOS chips IC30 and IC31 look to have been replaced. I found one 
broken trace to IC31 and one broken trace to the big processor. When 
these had been bridged, the octave selector, PW/PWM/waveform 
selector, SUB OSC selector and MG MOD selector now seem to work like 
normal. There is still something not right with the 367. Bank "D" LED
and Program "4" LED remain lit at all times, even during the reset 
and DAC adjust procedure, and recall of stored patches is very 
partial.

 It's pretty clear that both the KLM-367 and KLM-366 have been quite
heavily contaminated (years AFTER initial battery leak cleaning) and 
need a "deep" cleaning. I'm not exactly thrilled at the thought of 
having to desolder all the trimmers on the 366, but it looks like I 
may have to...

 I tried to adjust the sour sounding oscillator with some success, 
but the pitch of all oscillators tends to drift. It may be that there 
is still a problem stopping the MG from modulating the VCO pitch when 
it's not supposed to, as there is a (very) LF pitch modulation that 
kind of comes and goes. 

 Lots more to look into here...    

Thomas