For $200, you can't go wrong !! (IMHO). Take it to a good tech and spend $400-500 on repairs and you'll still come out ahead.
Too many posibilities to do much good via text.
1) Power supply (esp. op-amp rails)
2) Broken/corroded output jack (Does headphone out work?)
3) Dead volume pot.
4) Mice/idiots at work inside.
5) Dead VCF
6) Dead VCA
"A thing may seem impossible...until it's done."