Vintage Synth Repair

Hi, 

I am the owner of a Polivoks, that has some problems now.

This started while playing with the unit, when it was switched on and 
was on hold for a while.

The Osc�s are totally detuned, sounding like somebody has added a ring 
modulation or FM all the time. Furthermore, there is a static tone, 
like if you add an a-440 tone to the output. 

When you turn up the Mod-knob in the VCA-section, the deep static tone 
is increasing. 

Somebody any ideas?

Regards,

Ambrosia