Discussion about the Korg PolySix synthesizer

hello all,

i just picked up a polysix which has some serious issues.  it will
intermittently produce something which almost resembles a proper
sound, but about half the time i get nothing at all.

it has obviously suffered the infamous battery leakage as you can see
in this picture:

http://i67.photobucket.com/albums/h313/botcore/DSC01168.jpg

a new battery has been installed (by somebody before me) but it looks
like that is as far as previous repair attempts have gone.

i have removed the board and will try cleaning it to see what happens,
but before i get into serious repair i'm hoping somebody can tell me
what else i might want to check for so i don't waste the effort only
to find out it wasn't the problem.

any help would be appreciated!