It's probably the volumn control device. It's hard to get stuff like that fixed these days when everything electronic is just replaced. You may be able to find some place to send it to doing a google search if there's no one local. I think it's made by Panasonic. CD units on e-bay are running over $200. I was lucky to find one in a PYP yard for $15. One's with just the tape head are pretty cheap. If you can get the knob off try spraying some contact cleaner into the pot to see if that helps.