Vintage Synth Repair

Hello,

I have this Roland sh1, that sunddenly is doing a very wild OSC things.

The pitch doesn't respect anymore the CV from the keyboard and also
from an external CV GATE sources 
+ 
plus the pitch is more than proportional to the KCV 
+ 
oscillate wildly, from the the standard intonation, like there is a
fast S&H with random summed to the main voltage .

any idea ? 
The synth has the uA726: could be the culprit ? (I have also a mini
and a teisco with 726, but this the first time I'm getting the problem)

thank you
at