IBM System Storage Subsystem DS5020 - Manual (Page 171)

4. Unpack the new power supply and fan unit. Save all packing material in case
you need to return the failed power supply and fan unit CRU.
Note: The new power supply and fan unit CRU comes with an instruction
sheet and label sheet. The instruction sheet provides instructions on
placing the applicable labels on the power supply and fan unit CRU to
mark the LEDs correctly. The label sheet contains the peel-off labels
that you actually place on the power supply and fan unit CRU.
5. Using the information provided on the instruction sheet, place the labels on the
power supply and fan unit CRU to correctly mark the LEDs.
6. Turn off the power switch on the new unit.
7. Check the Fault LED to locate the failed power supply and fan unit. If a fault is
detected, the amber Fault LED is on.
8. Verify that the Service Action Allowed LED is on. Do not remove the power
supply and fan unit if the LED is off. For more information about the Service
Action Allowed LED, see “Service Action Allowed Status LED” on page 121.
Statement 1:
Chapter 5. Replacing components 141