The PT-110 failure is often due to a broken lever that pushes the feed wheel against the tape. With no tension, there is no tape feed. I have repaired 4 or 5 of these (all my units have had this problem). NOT an easy repair. Epoxy alone won’t hold. If you open the door on the back to replace a tape cartridge, and notice the white lever at the lower edge is “floppy loose”, it’s broken. You should feel spring tension against this white lever as you press the door back in place - which verifies it’s NOT broken. My repair involves disassembly, a thin layer of plastic epoxy to hold it together so I can add a specially shaped piece of spring wire to re-enforce the weak part, then a thicker layer of tougher 907 epoxy to add the strength and hold the special wire in place. Tricky part is to keep the epoxy from getting into the wrong spots.