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

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Subject: RE: Another P6 back to life

From: <rufushaw@yahoo.it>
Date: 2013-10-23


Hi there,


Some updates.


I've made some swapping tests, and these are the result.


Broken P6 had some issues on panel controls, on octave transpose knob 16' 8' 4' and MG level knob.


I've swapped the KLM367 with a working one, and both these issues disappeared, so, the panel board with knobs is ok and the problem is somewhere on KLM 367.


I've ordered some Vactec VTL5C3/2 to change the PC1 IC, hope this will be enough to restore the voice board.


So questions are:


Which traces / ICs manage the OCTAVE TRANSPOSE switch 16' 8' 4' 

Which traces / ICs manage the MG level pot values?


Any help is very much appreciated, thanks.







---In polysix@yahoogroups.com, <rufushaw@...> wrote:

Hi all there,

I've picked up another Polysix in good external conditions, but dead on the electronic side.

It had the common battery leakage on a small area not so bad than others that I've already repaired, so I've restored it at usual,

Now some minor issues are still there.

Octave scaling is irregular, so, suspecting a faulty HTV1501 photocopupler as written in other topics, I've swapped the voice board with a spare working one, and the issue disappeared, then the issue might be on PC1.
I can't understand which spare is better for this IC, someone says VTL5C1, some other says VTL5C3, 

MG level doesn't works properly.
This issue is driving me crazy.
Frequency and Delay Pots are working flawless, but once engaged, it's impossible to dim or turn off the LFO modulation effect by turning the "level" pot.
The pot itself is working, either the IC2 4051 on control board is working, i've followed the Data and A B C cables for signals routing and they are without any interruption.
I've checked the IC6 also, perfect.
Connection cables are ok.
Tips about where to dig?

More than this, it doesn't save patches.
I've checked the memory chip's electrical signals, and it seems working properly, giving the same responses than the working one.
.
I have also made the Lithium battery mod as shown in service manual appendix, but there's no way to save patches,although  the buttons are working properly.


Any help is very much appreciated, thanks.
Sorry for my bad english,
Bye,