While I don't know about the Perq systems, I do know a
little bit about the Micropolis drives. The main
problem with these is that the rubber bumper for the
head stop turns to goo. When the heads are parked,
they get adhered to the bumper, and then the drive
will no longer be able to come ready - the heads never
load. This can be repaired by opening the drive and
removing the offending bumper. Search back in the
archives for Micropolis, there have been many good
posts about this in the past. Of course, there is a
certain amount of risk involved when opening a hard
drive and all that, but once again, others have
explained this much better than I ever could.
-Ian