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