AT&T MERLIN LEGEND Release 3.1 Maintenance And Troubleshooting Manual page 120

Processor Problems
Replacing the Processor Module
A failed processor module must be replaced immediately.
To replace the processor module, follow the steps below.
1 If possible, save system programming.
See Appendix D, "Backing Up with a Memory Card." To back up onto a floppy
disk, see System Programming and Maintenance (SPM) .
2 Power down the system.
a Turn off the power supply on the basic carrier.
b Turn off the power supply on each expansion carrier.
c Unplug the auxiliary power units (if present) from the AC outlet.
3 Unplug the D8W cord(s) connecting the SMDR printer and/or system
programming PC.
4 Remove the processor module.
5 Inspect the processor module for any visible problems.
6 Inspect the carrier.
7 For Release 3.0 and later, skip to Step 8. For Release 2.1 and earlier,
install a feature module in the new processor.
Use the feature module from the old processor if it appears to be functioning
correctly; otherwise install a new feature module. See "Replacing the Feature
Module" that follows this section.
8 Install the new processor module.
9 Power up the system.
a Plug the auxiliary units (if present) into the AC outlet.
b Turn on the power supply on each expansion carrier.
c Turn on the power supply on the basic carrier.
The system automatically cold-starts.
10 Perform a System Erase (frigid start).
See "System Erase" above for instructions.
11 Restore system programming using one of the following.
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Control Unit Problems