Discussion about the Korg PolySix synthesizer

Bonjour (ou "buenas dias"?) Bastien,


> KLM 367 : Battery leakage
>
The first thing before you continue with anything else: desolder all IC 
is a wide range around the battery, clean the board, test each trace 
with a beeper and - if required resolder the traces or fix them with wires.
Then solder-in IC sockets and insert new ICs. Don't use the original ICs 
any more - the battery acid already has crept into them and will kill 
them some years later.

As sockets please use the good industrial style ones with round 
receptors like these: 
https://cdn-reichelt.de/bilder/web/artikel_ws/C130/GS_20P.jpg. Do not 
use these https://cdn-reichelt.de/bilder/web/artikel_ws/C130/GS_20.jpg 
with only a single spring receptor.

I replaced all ICs from the left boarder up to IC23/24. The CPU cannot 
be replaced, but you still should desolder it, and socket it. Also 
replace the diodes in that area.
The ICs and sockets are dirt cheap. You won't spend mor than 25 Euros. 
But it will be a hell of work.

You need a electronic desoldering station. Do not use a mechanical 
desoldering pump. A mechanical pump will destroy the traces which are 
already weakened from the battery acid.


Unless you did not do this, you don't have to continue.



> KLM 366 : Voice 3 doesn't make any sound
>
This has nothing to do with the battery leakage. Here you have to check 
systematically:
Is there a saw at Q7? Is a Saw/ Rectangle at the Testpoint near C48.
If yes:
Are the Key-CV, Cutoff-CV present at the  Filterchip?
Is the Gate present at the envelope?

In my Polysix a CD4066, which does the envelope and 
Rectangle/Saw-Switching, was dead. But this is only one out of many 
possible causes.


> KLM 369 : Octave, waveform, PW/PWM, PWM speed and sub osc pots and 
> switchs doesn't affect the sound in anyway. Will check the whole card, 
> connectors, traces etc
>
This is not KLM369, but the cause will be most likely the battery 
leakage. The ICs 28 and 29 (which provide the data for these parameters) 
are enabled by the CPU port P24. The corresponding trace runs under the 
battery. (PWM speed won't work as long as the wavefrom select does not 
work). -> So GOTO TOP: First do a restauration of the battery leakage.


Florian