TK50/TK70 Info

If I'm not mistaken, TK70 drive can read but not write TK50 tapes. I have very limited experience with this family of drives so far, but what little I have is not good. Pictures: https://twitter.com/nf6x/status/617511461452013568 https://twitter.com/nf6x/status/617519989721923584 Maybe my tapes need baking or something to keep the oxide from shedding? I haven't tried it yet. Unfortunately, my failure mode results in a labor-intensive fiddly manual tape extraction job followed by manually rewinding tapes into cartridges designed to make it very difficult to do anything manually, so I haven't found the motivation to resume experimenting yet. If and when I resume experimenting, I might look into making some sort of gizmo to let me unlock the two cartridge spool locks and then manually rewind the tape, without needing to disassemble the cartridge with springs popping out all over the place. Maybe something 3D printed the depresses the latches, with a crank that engages the spool?