Just picked up a Sears SR2100 series model 2132 at a yard sale.  Tape doesn't play unless play button is held.  Right channel has an issue..will pop/rattle but no audio...although can hear muted audio at full volume.  Same issue through headphone jack.

Any suggestions on what to check to narrow down the issue?

Oh, and seen an old post from "Obtuse",  you still have that old 2132 manual?