Discussion about the Korg PolySix synthesizer

I have had a Korg Poly6 for many years and loaned it to a mate for
the last 6 or so years. It came back with the leaky battery problem.
I have an electronics tech friend who replaced the battery for me and
also IC's 30 & 31 on the same board. Everything seems to work OK -
except for it doesnt make any sound at all and I have no LED's up on
the "KEY ASSIGN MODE" bank. I have found your websites to be very
helpful so far and would like some help please. Is the problem likely
to be on the same board as the battery ? If so where and what should
I be looking for ?

TIA
Steve

yeah, I would say that the problems are on the same board. they
almost always are. First off you can track down the schematics for
the board, but they really aren't that necessary (if even useful)
unless you have parts missing, which I doubt you have.

ANyhow....

take the board out that has the battery on it... gather some X-acto
knives (regular razor blades will work as well) and some fine hook-up
wire or something similar. Also, many times a magnifying glass is
helpful.

examine the board, everytime you see a chipped away or corroded trace
(the wire thingies), you will need to scrape all the bad away; look
for blackened traces and the such. Most likely you will need to
'replace' it with some of the hookup wire. THis can be done by
soldering it exactly over the broken trace (make sure you scrape the
coating off until you get enough good trace to solder to) or by
following the trace itself to both ends and solder the wire to the
components that it connects.

This can take a very long time, or you can find one or two that are
bad, replace them and bingo, you got the Motts.

My board had the battery replaced (with an OE battery) and traces
repaired before I even bought it. I replaced the battery again (using
oldcrows directions), and then fixed yet *more* traces. The synth
worked fine itself, but those traces on the "battery board" were
keeping the majority of my "patch memory" from working.

-ben

On Tue, 11 Sep 2001 stef@foxall.com.au wrote:

> I have had a Korg Poly6 for many years and loaned it to a mate for
> the last 6 or so years. It came back with the leaky battery problem.
> I have an electronics tech friend who replaced the battery for me and
> also IC's 30 & 31 on the same board. Everything seems to work OK -
> except for it doesnt make any sound at all and I have no LED's up on
> the "KEY ASSIGN MODE" bank. I have found your websites to be very
> helpful so far and would like some help please. Is the problem likely
> to be on the same board as the battery ? If so where and what should
> I be looking for ?

No LEDs for key assign mode means that something is wrong on the KLM-366
voice board. The first thing to check is that all the cable are attached.
Next, by pressing keys there should be small LEDs on the board itself that
light up to indicate which gate circuits are active. If these don't light
then it is very likely the microcontroller on the KLM-366 has failed.
This can be replaced with similar part that, while not factory-programmed
with the necessary code, can be programmed in a standard device programmer
and used on the KLM-366. (The original part is an Intel 8049, the
replacement is Intel 8749, which is an eraseable/programmable version of
the same thing).

It is possible that problems on the KLM-367 (board with the battery) are
interfering with the KLM-366. If there are any traces that were corroded
by the old battery, they'll need to be fixed.

Crow

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