Discussion about the Korg PolySix synthesizer

I've been recovering this one, found in the flea market. Overall it 
had about 8-9 different faults that I fixed, leaving two problems.

The first is a bad SSM2056 chip which I need to find. The second i 
probably inherent in the discrete ciruit of the second oscillator.

Upon powering it up, that particular oscillator will be out of tune, 
till it gets to its max. internal temperature where the tuning of 
that VCO is geting more or less - stable.

All other oscillators are immediately in tune, no matter what is the 
temperatue inside the machine.

I, of course, tried to figure out what the bad component is by 
blowing with a straw on each and each of the suspected compnents, but 
blowingon every component on the circuit of that oscialltor which 
seems to be pitch related, seems to effect the pitch.

I also tried to switch transistors between the bad oscillator and 
another (working one) but the problem persisted.

Does anyone have any other idea / direction ?

Thanks