Vintage Synth Repair

Hi all,

I have a problem with a Kurzweil K2000 synth that has rendered it 
useless. The unit was absolutely fine one minute, and the next 
minute it started to produce an extremely loud buzz/hum from all of 
the audio paths (headphones, stereo mix outs, individual outs). I've 
tried hard resets, new system batteries, etc, but all no good.

If anyone has any idea what the cause of this may be (or how to 
determine the cause), and a possible solution, I would appreciate 
any advice you could offer on the matter.

I'm kind of desperate.

Thanks very much.

John