IBM 3745 130, Maintenance Information Procedures

Page: 175 / 361

3745 MAPs
Power MAP 3930: Power Control Subsystem Problems
Symptom Explanation Conditions That Could Cause This Symptom
Panel display or power indicator
not lit.
Machine will not Power ON.
Ÿ UEPO
Ÿ CB1 or any CP tripped
Ÿ PS2
Ÿ PCC card or Control Panel
Attention
Power may be present when nothing is dis-
played on the control panel.
Power supplies are sealed replaceable
units.
001
– Check at the control panel.
Are all indicators OFF or **** displayed?
Yes No
002
Go to Step 024 on page 2-23.
003
– Check for the presence of 28 V at the UEPO
switch (see Figure 2-3). Use a CE meter and
check for 28 V between:
Ÿ Position 5 and the ground of the switch on
the 3745 Models 130-170
Or
Ÿ Positions A2 and the ground of the switch
on the 3745 Model 17A.
Are 28 volts present?
Yes No
004
– Check the position of CP2 on the primary
power box.
Is CP2 ON?
Yes No
005
– Switch CB1 OFF.
– Switch CP2 ON.
– Switch CB1 ON.
Does CP2 drop again?
Yes No
006
Power ON the 3745.
007
(Step 007 continues)
B1
A1
C1
Battery
Rear View
J1
EPO
1
1 4
2 2 5
3
3 6
D C B A
Wiring Side
Detail C 01C-C1SW1
Figure 2-3. UEPO Switch
007 (continued)
– Check that the voltage select switch
(01H-B1/SW1) is correct for the
input voltage. Refer to Figure 4-37
on page 4-32.
Is it correct?
Yes No
008
Set the voltage select switch
(SW1) to the correct position.
Go to Step 005.
Chapter 2. Map for FRU Isolation
2-21