UPGRADING REPAIRING PCs

gently until the worm gear moves freely again. Reassemble the drive
and test it outside the case by running the data and power cable to it
before you secure it into its normal position.
Interface Circuit Boards
A drive’s interface circuit board (also called logic board) can be damaged
by shock, static electricity, or a power surge. Usually, it can
easily be removed from the bottom of the drive and replaced by a
spare circuit board from an identical drive with a bad read/write
head or stepper motor. Keep such failures around for spare parts.
Read/Write Heads
Because of the contact between the heads and disk, a buildup of
the magnetic material from the disk eventually forms on the heads.
The buildup should periodically be cleaned off the heads as part of
a preventive-maintenance or normal service program.
The best method for cleaning the heads involves the use of a commercial
wet-method disk head cleaner and a program that spins the
cleaning disk and moves the heads around the cleaning media.
MicroSystems Development (www.msd.com) offers the TestDrive
floppy drive testing program, which contains such a cleaning utility.
Depending on the drive use and the amount of contaminants
(smoke, dust, soot) in the air, you should clean the read/write
heads on a floppy drive only about once every six months to a
year.
Do not use standard 3 1/2-inch floppy head cleaners with LS-120
SuperDisk floppy drives; although these drives can read and write
to standard disks as well as the 120MB SuperDisk media, a conventional
cleaner will damage their special read/write heads. Check
www.superdisk.com for a SuperDisk-compatible cleaning kit.
Floppy Drive Hardware Resources
Whether they are built in or not, all primary floppy controllers use
a standard set of system resources:
• IRQ 6 (Interrupt Request)
• DMA 2 (Direct Memory Address)
• I/O ports 3F0-3F5, 3F7 (Input/Output)
Floppy Drives 145
These system resources are standardized and generally not changeable.
This normally does not present a problem because no other
devices will try to use these resources (which would result in a conflict).