Vintage Synth Repair

Greetings everyone,
I am new to the vintagesynthrepair group.
Recently I purchased a Farfisa Compact Combo. Currently, the organ is 
in transit to me. Age has caught up with it, and it does need some 
attention. The previous owner describes the problems being a few keys 
out of tune, a bit of static when played, and what sounds like a 60 
cycle hum. I am far from a electronics wizard, and don't want to go 
tinkering with something I don't know about. Any help? What would I be 
looking to pay to have the organ fixed?