AT&T MERLIN LEGEND Release 3.0 Installation Manual page 388

Power Supply Problems
Replacing the Power Supply
WARNING:
Beware of hazardous voltages; whenever the carrier connections are
exposed, use extreme caution; do not touch them directly or with any
type of tool. Follow ail procedures carefully.
To remove the power supply module, follow the steps below.
1 If possible, backup system programming on a memory card (Release 3.0
only) or floppy disk.
See System Programming and Maintenance (SPM) for information about
backing up to a floppy. For information about backing up to a PCMCIA
memory card, see Appendix D, "Backing Up with a Memory Card." If the
basic carrier's power supply fails, you cannot back up system programming.
2 Power down the system.
a Turn off the power supply in the basic carrier.
b Turn off the power supply in each expansion carrier.
c Unplug the auxiliary power unit, if present, from the AC outlet.
3 Unplug the system from the AC outlet.
4 Remove the power supply.
a Unplug the AC power cord from the power supply.
b Remove the ground wire attached to the grounding screw on the front of
the power supply module.
c Remove the two ferrite cores, if present, from around the AC power cord
and ground wire.
d Remove the power supply module.
4-10 Control Unit Problems