IBM 3270 Maintenance Manual page 300

1.
Set the Power switch on the system unit (and
expansion unit, if attached) to Off.
2. Remove the failing fixed disk drive from
either the system unit or the expansion unit
(see Section 5, "Removal/Replacement and
Adjustments").
3. Place the failing fixed disk drive on the
power-supply cover so that the logic board
faces up and the face plate faces the right
side of the unit, as shown below.
4. Connect all cables.
CONTINUE
OC,tober 1984 3-1700-13