Power Supply
If the power-on indicator is not on, if the power supply fan is not running, or the
computer will not power on, check for the following conditions.
If the above are correct, check the following voltages (see “20-Pin Main Power
Supply Connection”).
Check/Verify
FRU/Action
1. Verify that the voltage-selector switch is
set for the correct voltage.
Correct the voltage-selector switch
setting.
2. Check the following items for proper
installation:
Power cord
On/Off switch connector
On/Off switch power supply connector
System board power supply
connectors
Microprocessrs connection
Reseat.
Check the power cord for proper
continuity.
Power cord
Check the power-on switch for continuity.
Power-on switch
20-Pin Main Power Supply Connection
See “System Board Layout” on page H-5 for connector location.
Note:
These voltages must be checked with the power supply cables connected to
the system board.
1
10
11
20
Pin
Signal
Function
1
3.3 V
+3.3 V dc
2
3.3 V
+3.3 V dc
3
COM
Ground
4
5 V
+5 V dc
5
COM
Ground
6
5 V
+5 V dc
7
COM
Ground
8
POK
Power Good
9
5 V SB
Standby Voltage
10
12 V
+12 V dc
11
3.3 V
+3.3 V dc
12
-12 V
-12 V dc
13
COM
Ground
3-20
3745-XXA 3-20 3746-9X0: 6578 SPIM
Summary of Contents for 3746-900
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Page 173: ...Appendix A Safety Information A 11 ...
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Page 231: ...Appendix I Service Processor Part Numbers Copyright IBM Corp 2001 I 1 ...
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