I saw the Walkmans and they problems topic, and I think it's great. I thought that some people don't know that there are problems related to cassettes too, which makes us think that there is something wrong with Walkman. Before you think that, just check with other tapes. If any of the tapes preform better, just leave it in Walkman for continuous play (with autoreverse if possible) for at least few hours (some say full night, even). Let's face it, some tape are 40 years old. I don't think they were meant to be used for that long. Storage of tapes was a problem too, people moved them to basements or other places with high humidity / high heat etc. And even packed ones (NOS) could be damaged. Even MA-R (one I have is from 1979, 2nd one is from 1980), reference tapes, made 'bulletproof', has issues with winding and there is a problem with tape. There are binding problems on TDK tapes (mostly metal from 1988 and later), cassettes aren't that well made (TDK too, same time - suggestion is to transplant tape to different housing), railoading (mostly newer TDK, but not only).
You can have just as many problems with the Cassettes as well as the players, like you said they are all very old. Anything old can be problematic, even old people too have problems.
@Raul I think it's a great idea to discuss about cassette problems. If you have a specific list with models that are problematic, please share it ! It would be helpful to know if some of these cassettes have problems, especially NOS ones, because they're not worth buying if problematic. An example that comes to mind are the BASF LH, of which I bought some used out of curiosity: I liked the design and the sound was very good for a TYPE I. However, near the end of the tape it started squeeling like mad and shedding a lot of oxide. I later read that there's a possible problem with the forumation of that tape. Asked a question about that here: https://stereo2go.com/forums/threads/best-audio-cassette-from-80-90’s.5716/ and did not get and answer yet. Another aspect I would like to share is in regard to all BASF cassettes with that security mechanism. Have seen on cassettecomeback YouTube channel a FerroChrom that was destroyed by that security mechanism just by winding it. People may have different opinions about that, but in my opinion that SM should be taken out and it's also preferrable only to buy those cassettes new, as the used ones may already have damage from being used with the SM in place. On average, my experience is that good quality cassettes tend to have less problems that low quality ones (especially the old pre-recorded), but of course that's not a rule and there are always exceptions.
There was a discussion about tape becoming sticky over time on this forum a while back. A problem I have with a series of BBC radio broadcasts made by the stars of the original BVC TV series "Dad's Army". Some just out of the shrink wrap jam about half way through either direction and others are worse but over time even the ones that played through OK initially eventually lock up during play. FF and REW will move the tape again but pressing play usually means the problem reappears fairly soon after. There were a number of solutions to relube the tape surface but I have not tried to do this with mine. Never had this problem with TDK cassettes however. Only one or two SA's from the early 80's have lost their brightness but I figured some tape uses better chromium oxide quality than others and doesn't degrade noticeably.
