Vintage PANASONIC RA-6600 Receiver

Vintage PANASONIC RA-6600 Receiver

Vintage Panasonic RA-6600 AM FM Stereo 8track Receiver.
Very Clean unit.

I tested the unit, and all switches and knobs work, and 8track plays, but sound will only come out of one speaker.  The other speaker only has static.  It only does this while playing the 8track, all other functions are fine.  Unable to test the record feature on 8track player because I don''t own a recordable 8track tape. The power knob is missing the plastic cap-see pictures.