IBM 5280 Manual page 285

A G
1 2
POWER MAP
D.C. DISTRIBUTION
PAGE 3 OF
(Step 021 continued)
Does CBI trip again?
Y N
I
022
3
Problem is in the diskette
drives, keyboard or DC
distribution cables.
Reconnect cables
problem is isolated.
023
Problem is in the
board, cards or
distribution cables.
until
Logic
DC
- Remove cards and cables
until problem is isolated
(MIM 455, 501 and 531>.
024
- Defective power supply and AC
capacitor C7 (MIM 470 and
476).
025
- Power off.
Disconnect the plug at J5 (MIM
451 and 457).
Replace the open fuse.
- Power on.
Does the fuse open again?
Y N
026
The J5 connector
AC voltage to
Unit.
distributes
the Display
Use
diagram
diagram
the AC distribution
MIM 453 and wiring
MIM 457 to locate the
cause of of overload in the J5
circuit.
H
MAP 8030-3
027
- Check for a. ~efective fan.
- If necessary, remove fan from
TBI and TB3 (MIM 451 and 457).
- If no problem is found with a
fan, replace the power supply
and AC capacitor C7 (MIM 470).
EC840874 PEC8397S7
H MAP 8030-3