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