i just worked on 2 ( super drives on from Classic and one from FDHD) and a Mac SE with 2 800k drives,
i had issues where the drives were not working before and after clean and lube, i found when you take the 2 phillips screws out and pull the top and bottom head out as an assembly there is a spring that is normally completely out of sight unless you pull the whole head assem out...
the spring has a 3 position perch, low/med/high tension settings for clamping pressure across the 2 heads top and bottom,
I found that what ever the setting is, usually low or Med, just move the spring to the next setting (more tension)
the spring seems like they put a dab of epoxy on it, but if you grab ahold of it with some small (electronics) needle nose pliers,
the epoxy will let loose and then you can reposition the spring,
in my case i was able to get all the drives to work, found all this out by trial and error, and literally tearing one of the drives down to all its basic parts.
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