Nortel DMS-100 Series Maintenance Manual page 601

When the cycling starts for a specified drawer, remove the fuses again.
Proceed to the next drawer. This action isolates all the drawers that cause
the problem.
6. When you isolate the drawer, insert the fuses back for the drawer or
drawers. Unplug the controller cable on the back of the line drawer. The
controller cable is the center cable, labeled C and D.
7. Replace the 6X54 card in the isolated drawer and connect the controller
cable back into position.
8. If the cycling continues, unseat the line cards one at a time in the suspect
subgroups to locate the defective line card. The line drawer can require
replacement.
9. Contact the next level of support.
10. This procedure is complete.
Advanced troubleshooting procedures 12-9
DMS-100 Family OPM Maintenance Manual XPM14 and up