Vintage Synth Repair

hello,

i left my magnus electric organ at a friend's house for a few weeks 
and when i brought it back home and tried to play it, it was totally 
jacked.  it powers on, but when you play the keys either a garbled 
note comes out or some evil static, or no sound at all.  i noticed 
some water stains on some of the keys so it looks like somebody may 
have spilled something on it.  i know absolutely nothing about 
electronics repair - can anybody help me out?  would cleaning it help 
or is it totally fubar?  

thanks,

tim