The Kawai & Teisco Analog Synths Group

I recently bought an sx210 "as is" from a thrift store for very cheap.
 Unsurprisingly, it doesn't work.  I am not familiar with synth
technology so the best description I'd be able to give is that it
sounds like there is something wrong with the filters, as they are not
manipulating the sound much.  I do get some sort of tone but as long
as the synth is tunred off, the tone is playing.  It was only eight
bucks and I figured I could get it fixed.  Can you guys recommend a
place that would be able to find the problem and repair my sx210?