have some specs but other than that they're
useless. I have the service
manual for the drive used in the 9121 but that's all.
I have that manaul too (it's entiled something like 'HP 3.5" floppy disc
drive service infrormation'). Mine has a section specifically on the
9121, which includes the PSU schematic and a complete parts list for the
controller board (but no schematics for the interesting bits).
-tony