Micropolis head fine adjustment jig

thingiverse

This is a jig for readjusting heads on vintage 5.25" micropolis SCSI hard drives. A common issue with these drives is that the rubber bumpers on the head assembly can wear out, allowing the head to wander off its servo track. Connect your oscilloscope to the SS pin on the controller, attach the jig, and slowly turn the adjustment screw until you see a valid servo signal appear on your scope's screen. In some cases, the drive may suddenly come back online as soon as it detects the valid signal. This jig requires an M2.5 heat-set insert for the adjustment screw, which is pressed into the inner side of the fixed piece. The pivot between the fixed and lever pieces uses an M2.5 screw. Use this jig at your own risk. I attempted to save a drive using it, but ultimately failed due to multiple other problems that arose during diagnosis and repair efforts.