IBM B50 - Manual (Page 41)

Step 1240-3
The failure may be caused by the last memory module installed or the system board.
To isolate the failing FRU, do the following:
1. Power off the system.
2. Exchange the last memory module installed.
3. Power on the system.
Does the system stop with a memory checkpoint displayed on the operator
panel?
NO Go to " MAP 0410: Repair Checkout " in Diagnostics Information for
Multiple Bus Systems.
YES Go to “Step 1240-4.”
Step 1240-4
One of the FRUs remaining in the system unit is defective.
1. Power off the system.
2. Exchange the following FRUs in the order listed.
System Board
Power Supply
3. Power on the system.
Does the system stop with a memory checkpoint displayed on the operator
panel?
NO Go to " MAP 0410: Repair Checkout " in Diagnostics Information for
Multiple Bus Systems.
YES 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,
go to “MAP 1540: Minimum Configuration” on page 2-17.
Chapter 2. Maintenance Analysis Procedures (MAPs) 2-11