he can try actually. by chance if any dust particle do not
happen to settle on the teeny weeny micron gaps between the
actuator readout tip and the platter, and he somehow manages to
have the correct tool head sna d trouque equippment to dismantle
the actuator arm from the drive and replace with a new one whtou
compromising the sensitive cabling along the way - why not?
the aim of clean room is not to have dust settling on the
platter face, since when the platter spin the sensitive gap between
the readhead tip and platter read face if is obstructed by
particles or dust or reasonable size may scracth and damage tthe
platter, making datda unreadable, e.g as in creating a bad
sector.
However google online there are still people who managed to open
up the hdd and close it back and get it to run like no tomorrow.
iwonder why, hope the vacumm and air difference before and after
case open negligible.