Vintage Synth Repair

Hi gang,

I bought a beatiful Korg MS-10 last week, but couldn't travel to 
check it out first. There are some problems that I'm hoping someone 
here can give me a hint about.

Firstly, the keyboard doesn't trigger the synth itself. I've neatly 
circumvented the problem by triggering it from another vintage 
synth, so no biggie. 

Main issue is that all the oscillator waveforms except for Noise are 
completely silent. Well, if the volume is very loud I hear a slight 
noise signal when keys are pressed and released. Everything after 
the VCO seems fine, the filter self oscillates like crazy (beautiful 
timbre!), and the filter works fine with the Noise waveform. All the 
LFO modulations work too, aswell as most of the patch panel outputs 
when I patched them directly to my mixer. The thing I like most 
about this synth is that the LFO shapes aren't perfect, so if I mod 
the filter cutoff in self oscillation, with a sawtooth, I get a 
wonderful "smack" when it resets the cycle.

But kind of a drag when only filter oscillation and Noise are the 
only things coming out of the machine.
Envelopes work fine too btw.

So I've narrowed it down to either dead VCO (is it a chip or a 
complex circuit?), or a problem with the VCA section so the VCO 
signals don't get through to the filter. But then I shouldn't hear 
the Noise signal either and be able to filter that?

There are very few analogue repairmen here in Norway, and the few 
there are charges LOTS. So if anyone could give me a pointer, maybe 
it's simply a loose wire or something..I'm no electrician so I 
didn't open it up and check..but you recognize the symptoms, shout 
out :-)

Thanks for reading all this.

-Tom from Norway-