Vintage Pioneer SX-660 Receiver for Parts or Repair

Vintage Pioneer SX-626 Stereo Hi-Fi Receiver for parts or repair. It powers on and produces sound but it's very, very quiet. I have to crank the volume up all the way to hear anything and there's some distortion to the sound. Also, the tuner won't pick up a signal. It's pretty clean cosmetically, has typical wear for a 45+ year old piece of equipment. The face is clean though it's missing one knob, and the case is clean though the left rear top and bottom corners are a little dented in. Otherwise it's a good looking amp and could be a very nice piece of equipment. Make me an offer!