IBM H Series Installation And Service Manual page 61

Step 1520-8
Note: Either the Service Processor (Model H50), the I/O board, the System board
or the power supplies may be defective.
To test each FRU, exchange the FRUs that have not already been exchanged in the
following order.
Service Processor (Model H50)
I/O board
System board
Left power supply
Right power supply (if installed)
1. Turn the power off.
2. Unplug the power cables from the power supplies.
3. Exchange one of the FRUs in the list.
4. Connect the power cables to the power supplies.
5. Turn the power on.
Does the fan in the power supply turn on and the power LED on the operator
panel come on and stay on?
NO Reinstall the original FRU.
Repeat this step until the defective FRU is identified or all the FRUs have
been exchanged.
If the symptom did not change and all the FRUs have been exchanged,
call your service support person for assistance.
YES Go to "MAP 410: Repair Checkout" in the Diagnostic Information for Mul-
tiple Bus Systems.
Chapter 2. Maintenance Analysis Procedures
2-27