PC disk drive termination
ard at p850ug1.demon.co.uk
Thu Oct 20 19:26:14 CDT 2005
Somebody earlier claimed that IBM didn't bother with termination on the
disk drives in the PC family.
I've just looked in the 'Hardware Maintenance and Service' manual for the
PC/AT. This is the only HMS manual I have (I don't normally bother with
boardswapper guides), but I would be suprised if the same principles
didn't apply to the PC.
Anyway, the manual says :
o The terminating resistor must be installed on drive A (top unit).
o In a system unit with 2 diskette drives, remove the terminating resistor
from drive B (bottom unit) for proper operation.
o The diskette drive end of the signal cable is attached to diskette
Fixed disk drive
o The terminating resistor must be installed on fixed disk drive C (left
o In a system unit with 2 fixed disk drives, remove the terminating resistor
from fixed disk drive D (right unit) for proper operation '
There are diagramss showing the location of the terminating resistor pack on
the drive PCB that I can't sensibly reproduce in ASCII.
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