Discussion about the Korg PolySix synthesizer

Hello! I picked up a Korg Polysix recently and I've been trying to bring
it back to life. Nothing I've done has changed anything yet so I'm at a
bit of an impasse and I'm hoping someone out there might be able to help
me narrow down what I should do next. I know how to use a soldering iron
but I'm a complete beginner at repairing circuit board traces.

Let me give you the symptoms.

1. It sounds like it's gone absolutely mental with constant oscillation
and other insanity going on from the moment I power it up.
2. The Bank D and Program 4 buttons are constantly illuminated after
powering up.

After cleaning up most of the corrosion I could find around the battery,
it really didn't look as bad as I thought it might so I went ahead and
just installed a Lithium battery holder (using Old Crow's guide) and
tried powering up again. Nothing changed.

After that, I went back in and removed the IC31 chip (74LS08) and tested
all the traces in the area with a multimeter. Every trace I tested gave
me a happy little beep, even the uglier looking ones that were near the
old battery, so I went ahead and soldered in a new socket and 74LS08
chip at IC31. Powered up. Nothing changed.

Now, I'm not sure what to do. Did I miss a trace? Should I put jumper
wires on the ugly looking traces even if my multimeter says they're
conducting just fine? Should I replace the other ICs that were near the
battery like IC30 even if they look fine?

I recorded a sound demo. For the first 40 seconds I don't touch a thing,
then I start to experiment:


Bank D and Program 4 constantly illuminated:


First sight:
  <http://imgur.com/Wv173WQ>

After initial cleanup:
  <http://imgur.com/M8POlkz>

Installed battery:
  <http://imgur.com/Pj3kDFT>

Replaced IC31:
  <http://imgur.com/Nab9GYz>




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