Problem with my Panasonic RX-C50

Hi,
I picked up a Panasonic RX-C50 recently and everything on it seems to work fine but the volume is cranked all the way up and I'm afraid of blowing the speakers. I tried some contact spray but that didn't help. I haven't cracked it open yet but I was wondering if anyone else has had a problem like this before I dive into it. I know enough about electronics to be dangerous.

Thanks for any help!

try cleaning the function selector buttons if there is corrosion in the controls it will impede the electrical flow , also working the controls back and forth will loosen them up .

I did try working them back and forth for a minute or two but I guess I'm going to have to take it apart and see if there is any corrosion there. Thanks!

There is either a short in the control circuit or a break in the ground portion in the same circuit.