UPGRADING REPAIRING PCs

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Chapter 5—Floppy, Removable, Tape, and Flash Storage
Where Floppy Drives Fail—and Simple Fixes
I spent several years on the road carrying around disassembled PCs
for use in computer-troubleshooting classes. Typically, I had more
floppy-drive failures than about anything else, due to the combination
of inexperienced students, rough handling by airline baggage
carousels, and the simple fact that a floppy drive is designed to be
used within the confines of a computer case. I learned how to fix
drives the hard way—when the only spare I had wasn’t working,
either.
The Drive Cover
The drive cover acts as a dust cover, which is obviously a good idea
for a drive that uses exposed, relatively soft flexible magnetic
media. However, a damaged or bent drive cover can bind the disk
ejector, preventing it from moving. The drive cover can easily be
removed and bent back into shape.
The Stepper Motor
The stepper motor moves the head actuator across the surface of
the floppy disk media, reading or writing data (see Figure 5.2).
Head mount
Head flex
cable
Guide shaft
Head connector
Stepper
motor
Mounting screw
Head
assembly
Worm
gear
Figure 5.2 An expanded view of a stepper motor and head actuator.
On a 3 1/2-inch drive, the stepper motor is often a worm-gear
arrangement rather than the band drive that was used on the older 5
1/4-inch drives. The worm gear is very compact, but can be jammed
by shock. To free it up, carefully unscrew the stepper motor from the
rear of the drive frame and move the head actuator back and forth