AT&T MERLIN LEGEND Communications System Release 2.0 Maintenance And Troubleshooting Manual page 101

Control Unit Problems
CAUTION:
Replacing the Power Supply
Whether replacing the power supply permanently or briefly for
troubleshooting, follow these steps:
1. If possible, save the system programming on a floppy disk by using the
backup procedure from the System Programming & Maintenance
(SPM) guide.
NOTE:
If the power supply on the basic carrier has failed, the system
cannot save the system programming to a disk.
Do not plug the power supply or the auxiliary power
unit into the AC outlet until you are ready to turn on the
system, as described in "Powering Up the System" in
Chapter 2 of the Installation guide.
Do not attach the power cord(s) to any building
surfaces.
Power Supply Problems
4-11