Ooh, I found a new (to me) failure mode. I found another box of tapes in the house, and got set up to try to recover from them. I replaced the elastic band, reassembled the tape cartridge and then slapped that baby in the tape drive and started off with a retension, which seemed to go fine. Then I tried reading and it immediately failed. I tried again and the tape transport started making the rattling noise I had seen on one other tape from the first batch. I felt around, couldn't tell where it was coming from. Took that tape out, and inspected it. I noticed that there was a little concave divot on the wheel that the tension band goes around where the pinch roller touches, maybe a millimeter or two wide. I put that one aside, and tried the next one. It was only a 450ft tape, not the normal 600. Replaced the tension band, reassembled and tried that one. This time, the retension started but then the pitch of the spinning changed and I noticed the tape wasn't moving despite the motor running at what seemed like normal speed. So I stopped the tape and ejected it, and this time I noticed a somewhat bigger circularly concave divot in the same wheel, as if the tape had stalled and the pinch roller had eaten into it. That kind of explains the noises I have heard on the other cartridges. I wonder what's up? Something not so happy. Maybe the pinch wheel is dirty and not enough traction on the drive wheel or maybe it's too small and doesn't have enough pressure/grip.