IBM 3270 Maintenance Manual page 503

System Board Removal
1.
Set the Power switch on the system unit (and
expansion unit, if attached) to Off.
2. Set the Power switches on all attached
devices to Off.
3. Unplug the power cord of the system unit
(and expansion unit) from the outlet.
4. Disconnect all cables from the rear of the
system unit.
5. Remove the cover of the system unit (5-100-2).
6. Remove all option adapters (5-20-3) (5-600-2)
(5-1700-16).
7. Disconnect the diskette-drive signal cable
III
and the system board power· connectors
B·
8. Remove the Math Coprocessor
II
,if
installed (5-700-2).
9. Remove the speaker connector
Ei1 .
10. Remove the system hoard mounting screws
Ill·
5-100-10 Maintenance Information