Discussion about the Korg PolySix synthesizer

Thanks in advance for reading...

I was lucky enough to recieve a polysix with a battery leakage
problem... removed the battery and retraced the board. The keyboard
sounds AMAZING first of all... but there are still some problems
with it. Everything worked... 'okay' before i did the retracing and
after replacing a couple of IC's. But unfortunately now, it seems
that VCA, Effects section, and the ADSR on the voicing does not
work. But the ADSR on the filter section does work. I am confused
as to what is going on. (Forgive me if i am a little vague on the
actual ICS replaced.. but they were the 7408's closest to the
battery. In anycase... does anyone have any suggestions to look
for? Does the VCA, ADSR and effect section lead to a single
section on the KLM367 that I need to look further into replacing
components etc? Any help would be apprectiated.

Forgive me, I don't have the schematics with me, but i do have the
orginals at work, so I can follow IC #'s.

Thanks in advance again...

Jay

I would check to make sure the logic signals on teh Q outputs of IC34 &
IC35 are changing when you change the 'effect select' (changes logic
levels on IC34 Q1,Q2,Q3 outputs), EG mode (changes logic level on !Q0
output) and EG intensity (IC35 latches the 4-bit codes for a programmable
volume level DAC.)

Also check to make sure the 7-wire cable from CN03 to the KLM-368
effects boards is not loose on either end as most of the IC34/IC35 control
signals go to CN03. Only IC34's !Q0 output goes to CN05-1 to tell the
KLM-366 what EG mode is used for the VCAs.

If IC34/IC35 outputs fail to follow the panel settings check the
continuity of traces between IC34/35's clock & 'D' inputs and the data
buss outputs of the 74LS08s (IC30/31). The clock signal show show
continuity from IC34/35 pin 5 to IC22 pin 36 (P2.5 on the 8048).

Crow
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On Wed, 22 Oct 2003, Jay wrote:

> Thanks in advance for reading...
>
> that VCA, Effects section, and the ADSR on the voicing does not
> work. But the ADSR on the filter section does work. I am confused
> as to what is going on. (Forgive me if i am a little vague on the
> actual ICS replaced.. but they were the 7408's closest to the
> battery. In anycase... does anyone have any suggestions to look
> for? Does the VCA, ADSR and effect section lead to a single
> section on the KLM367 that I need to look further into replacing
> components etc? Any help would be apprectiated.