IBM 5280 Manual page 284

D
1
POWER MAP
D.C. DISTRIBUTION
PAGE 2 OF 3
012
Power off.
Disconnect the plug at J2 (MIM
451 and 457).
Replace the fuse.
Power on.
Does F2 open again?
Y N
013
Problem ; s ; n t h e -5 Vdc
distribution.
Power' off.
- Reconnect the plug at J2.
Replace the fuse.
See the DC distribution
diagram"MIM 455.
Disconnect the diskette drive
and keyboard DC connectors.
Power on.
Does F2 open again?
Y N
I
014
Problem ; s in
the
drives, keyboard
distribution cables.
Reconnect cables
problem ;s isolated.
diskette
or DC
until
015
016
Problem is in the Logic board,
cards or DC distribution
cables.
Remove cards and cables until
problem ;s isolated (MIM 455,
501 and 531).
Defective base PC board (MIM
474) •
B C
1 1
MAP S030-2
017
- Power off.
Disconnect the plug at
J2
(MIM
451 and 457).
- Replace the fuse.
Power on.
Does Fl open again?
Y N
OlS
Problem is in the +S.5 Vdc
distribution to the Logic
board.
Reconnect the plug at J2.
- Remove cards
is isolated
531).
until problem
(MIM 501 and
019
- Defective base PC board (MIM
474)~
020
Power off.
Disconnect the plug at
45 1 and 457).
J2 (MIM
- Reset CBl.
- Power on.
Does CBl trip again?
Y N
3
021
Problem is in the +5 Vdc
distribution.
Power off.
=
Reconnect the plug at J2.
Reset CB1.
See the DC distribution
diagram MIM 455.
Disconnect the diskette drive
and keyboard DC connectors.
Power on.
(Step 021 continues)
ECS40S74 PEC839787
G MAP 8030-2