Korg Poly61 repair

Just got a Poly 61 has a damaged main board due to battery leak, not really bad couple of broken traces , soldered wire to bypass those areas, but I still have a problem, when I power up got a constant tone - lowest C can be heard with low volume, if I start to play goes away and every function works normally but after a while suddenly an other note comes one , if I play goes away and everything is normal again and minutes later starts again same problem
Any idea what can be wrong

I would double check that all the damaged traces were repaired - it’s easy to miss one, and that can lead to a sort-of-working keyboard, with strange issues remaining. Another possibility is that the battery corrosion can spread through the traces, and damage nearby components. So an IC or other component might be damaged.

Yes that’s right, just found two more broken traces under the 12 pin connector so I fixed those and - miracle- everything works!
Thanks appreciate your help
I saw you have a 3.6 V lithium battery for this keyboard I may place an order for that
Right now got a 3.2 V lithium phosphate couldn’t find the 3.6

Great news! Love a success story!

Yes , is little challenging to bring back to life an old equipment but is fun too, got this Poly 61 for a 100$, cosmetically excellent shape from a guy who kept this in a soft case for 2 decades in the storage.
More fun coming today, getting Ensoniq ESQ-1, I’m lucky this year got a Juno 60 and Yamaha CS 50 both for reasonable price