HP 20-Feb - Manual (Page 172)

170 Replacing the Redundant Power Supply Chapter 5
Replacing the Redundant Power Supply Module
Caution When replacing the entire power supply module, note that the
library does not have redundant power backup until the new
module is installed. See page 170 for the procedure for
replacing individual power supply units.
1. Disconnect the power cords from the library. Contact the system
administrator to ensure there is no activity on the SCSI bus.
2. Remove the power supply module by loosening the two 6-32 x .25 T-15
screws and pulling the module straight out.
3. Install the replacement power supply module by aligning the bottom of the
module with the bottom of the power supply bay.
4. Fully insert the power supply module into the back of the library.
5. Tighten the two screws.
6. The replacement supply comes with the entire redundant power supply
module and one individual unit. If you need to install an additional unit,
install one of the units from the original power supply.
7. Reconnect the power cord to the power supply.