IBM PS/1, Hardware Maintenance Service

Page: 143 / 304

043 (continued)
– Power on the system unit.
– Make a note of any error messages, if present, and press the Esc key.
IS THE SCREEN BLANK (DARK)?
Yes No
044
Go to Step 065 on page 2-109.
045
(From step 105)
– Power off the system unit.
– Disconnect the power cables to the system board and drives.
– Power on the system unit.
– Check the voltages at the power supply connectors to the system board
as indicated.
–
PWR
GOOD
– +
3
.7
5 t
o
6
.2
5 V d
c
– +
9
t
o
1
5
V d
c
– -
9
t
o
1
5
V d
c
GN
D
– -
3
.7
5 t
o
6
.2
5 V d
c
– +
3
.7
5 t
o
6
.2
5 V d
c
Figure 2-13. System Board Power Supply Connectors
ARE THE VOLTAGES CORRECT?
Yes No
046
(Step 046 continues)
Diagnostic Information
2-105