Discussion about the Korg PolySix synthesizer

I just did a battery transplant on a polysix i just got that had a 
leaky battery... not too bad, but there were a few (4-5) blackened 
traces around IC31, but they all tested as conductive, so I left them 
alone.So upon reassembly the LEDs for bank A and #1 stay on all the 
time. the other LEDs all go on/off as you push their buttons, but A and 
1 stay lit. And  new writing doesnt seem to enter the memory (no 
recall). Would those 4-5 traces around IC31 be the problem?  Could IC31 
itself be bad? what does it do? Is IC31 the "memory chip"? The rest of 
the board seems fine. Any ideas?