"Nothing wrong with the Sony Walkman portable Cassette players as far as I can tell. "
They had a weak spot in that connecting film between two parts (the one that cassette goes in and the one that closes it). I guess "interconnect" would be the closest name for it.
In the U.S.A. warranty was 90 days for labor and parts were six months. You ended up paying $45 for repair while they gave you $1 part free under warranty. Otherwise, nice machines.