Discussion about the Korg PolySix synthesizer

Hello All,

I recently acquired a PolySix suffering from the oft-spoken 
KLM367 Battery Leak.  When I removed the battery, I noticed that 
there was no white powdery residue from corrosion, just kind of 
a stain on the board.  Needless to say, my programmer is fried 
and needs to be repaired.  However, there are a couple of other 
problems with the synth and I am wondering if getting the 
KLM367 repair will fix these malfunctions, or whether or not my 
synth needs more extensive work.  I have tried contacting Scott 
Rider, who still has not replied, so I thought I would bring this 
question to the list.

First off, the synth works pretty well.  Most everything outside of 
the programmer works - and I have certainly come to love the 
sounds that I can coax from it.  

However, their are a few functions that do not work.  
1. The Octave Select Knob in the VCO only produces sounds in  
two registers (I think, though am not sure - the 8' and 4' 
registers) - the third position (16') sounds EXACTLY the same as 
when the keyboard is in the 4' register.  

2. The SubOsc will not produce any sound when switched to 
1OCT or 2OCTs down.  

3. The Modulation Generator can only be routed to the VCO, 
switching it to the VCF or VCA has no effect.

4. The Attenuator Knob does not work in both positions of the 
VCA's mode switch - it does not work at all.

I am wondering if these problems are a result of the KLM367 
malfunction, or if they are separate (perhaps caused by further 
corrosion).  I want to know whether or not the whole unit needs to 
be sent in for repair or just the KLM367.  Then hopefully I can get 
in touch with Scott Rider and see if he is available do the needed 
repairs.    

Thanks in advance for any help with my problems.
-Henry Till

> However, their are a few functions that do not work.  
> 1. The Octave Select Knob
> 2. The SubOsc will not produce any sound
> 4. The Attenuator Knob does not work in both positions

Hi,

I have no solution for your problem, but maybe a hint. I got a broken 
Polysix last weekend; maybe we have similar problems. 

My problem was that the P6 did produce sounds, but by pressing 
the "manual" button the synth always flipped to another program 
(randomly). Some programs cannot even be activated, and sometimes A1 
and A5 sometimes oscillate with each other. Sometimes programs 
activate themselves; sometimes the synth stayed in the manual-mode 
for a few seconds, and sometimes it was almost impossible even to 
access it.

So I changed the battery, checked the wiring and changed a handful of 
chips on the processor board KLM 367 that made a bad impression to 
me - but this did not solve my problem at all. Then I found out, that 
the program-flipping is somehow related to the MG-frequency (!!!): if 
the MG-LED reaches a certain phase, the manual-mode is kicked off and 
another program randomly selected. If the MG-frequency is high, it 
simply is difficult to get the right phase necessary to let the 
manual mode alive even for short time. Wired, he?

And here comes the link to your question. Trying to find out, how the 
MG-settings could affect KLM 367 I checked the connector CN06 from 
the poti-board KLM 369 to the programmer (KLM 367). If I disconnect 
the blue cable No. 7 (P10) everything stays stable and manual 
programming can take place. Some functions however are disabled -- 
these functions are: 16' setting on VCO (sounds like 8'), lowest 
suboscillator setting (sounds like just one oct. down), attenuator 
(some two or three settings work, most do not), VCA envelope-switch - 
exactly what you have experienced. The explanation is simple: If you 
have a closer look on the circuit, all these switches (including the 
attenuator, that is on board KLM 370) are connected with the 
programmer-board more or less via the same cable P10. So maybe you 
just have to check, if CN06 is in place or especially if cable P10 is 
broken or the conc´tact is corroded.

As it comes to my problem, so far I have no faint idea what P10 could 
have to do with the programmers disease and what Mod-frequency has to 
do with it. I dont even know, if the defect is on KLM 369 or KLM 367. 
I hope for a simple shortcircuit... May be someone else here has any 
clou. Please send me a message if you came any further.

All the best

Stefan