Insofar as the tape deck is used to record reception of amateur radio,
what's the best approach to repairing tape decks where the nylon-ish
band used for take-up has gone completely squishy (and resulted in
a build-up of tape inside the deck instead of on the take-up spool)?

I wonder if anyone has attempted a long-term solution by using the
miniature timing belts that are available these days?