IBM pSeries 690 Service Manual page 240

Step 152b-42
Attention: Before replacing the system backplane, call for support.
Replace the system backplane at location U1.18-P1.
Step 152b-43
Turn on the power.
Step 152b-44
Did the system stop with the same error code as recorded in "Step 152b-1" on page 218?
Yes Go to "Step 152b-45."
No The system backplane was defective. This ends the procedure.
Return the system to its original configuration.
Go to "MAP 0410: Repair Checkout" in the RS/6000 and Eserver pSeries Diagnostic Information
for Multiple Bus Systems.
Step 152b-45
Turn off the power.
Make sure all amber logic-power LEDs of all installed processor subsystem DCAs are off.
Step 152b-46
Has the system backplane been replaced?
Yes Call for support.
No Go to "Step 152b-42."
224 Eserver pSeries 690 Service Guide