Discussion about the Korg PolySix synthesizer

At 12:15 AM 11/12/03 +0000, you wrote:

>Not too bad *looking* in there: the battery had already been
>replaced, however it doesn't look like it was done thoughtfully:
>resistor R91 and capacitor C40 are still there; the new battery is a
>lithium battery (I know I have to get resistor R91 and capacitor C40
>out of there); and the negative side is attached to the trace that
>runs along the board's side with a thick piece of copper wire. It
>looks like a few traces may have been hit with some battery acid or
>something because they're ever-so-slightly bubbly.  All look intact.
>The most noticable thing though is that the solder on the holes
>around IC31 are corroded, although the legs of IC31 *look* fine.

Sounds suspicious to me -- would suggest having the battery & traces 
checked out by someone who's familiar with the circuit.


>Okay, so I'm going to have to clean that up.  Or should I bother and
>just buy Scott's replacement?  Here's why I ask:  I closed up the
>PolySix because I *had* to hear it.  Upon power up everything looks
>normal except that bank buttons A and B and patch buttons 1 and 2
>stay lit, although slightly dimmer than the brightness of the other
>LEDs on the other buttons (when turned on, of course).  It seems as
>though I can select those patches and banks, but the LEDs on those
>buttons never go off.
>
>Secondly, I can't really hear a difference when I select the
>different waveforms, and the octave doesn't change.

These control lines from the front panel feed into the board via a 
connector (CN06, if I recall correctly -- don't have the schematics in 
front of me).  That connector is near the end of the board that is most 
susceptible to damage from battery leaks (which I'm assuming happened in 
this case).

As far as the leds staying on -- if the functions work, it's not too severe 
a problem -- most likely one or two signal traces shorted by the leak problem.



>Would these problems be resolved after a good cleaning of the buttons
>and pots and obviously fixing the crappy battery replacement job?  Or
>are these issues more ominous and it would be less hassle to get
>Scott's board?

Depends -- some battery-damaged boards are an easy fix, and work just 
fine  once the damage has been repaired;  some take a lot more time & trouble.
So, it depends on how much time, effort & expense you're willing to put 
into it.
Where are you located?  Might be able to help out, at least as far as 
establishing the repairability of the board.

~GMM



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