Symptom; Main Circuit Breaker Off And All Leds Off - Nortel Meridian 1 Planning, Installation And Operating Instructions

Symptom:

Main circuit breaker off and all LEDs off

All the LEDs in the system are off and the circuit breaker on the power supply
in the cabinet is tripped. Use this procedure to clear the problem.
High room temperature or a power surge can shut down the system. Check
for these external conditions and if present, correct them then reset the
breaker.
You may need to replace:
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•
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Possible cause
Thermal overload
Defective circuit card in
the cabinet
Option 11C Compact
Chapter 25 — Fault locating and clearing
the NTMW11 power supply
the NTMW01 SSC card (if the fault is in the main cabinet)
the cooling fan in the top of the affected cabinet
any one of the remaining circuit cards in the affected cabinet
Action
Make sure nothing is blocking ventilation throughout the system.
Allow the system to cool for a few minutes then reset the breaker.
Make sure that the fan in the top of the cabinet is operating. If not,
replace the fan.
Check that the fan in the top of the cabinet is operating and is not
obstructed by items left on top of the cabinet. Listen to determine if
fan is operating. To further check or replace fan, remove top cover
to gain access to the fan. See
If the breaker trips, go to the next possible cause.
Unseat all the circuit cards in the cabinet except the power supply.
Reset the breaker.
If the breaker trips, the power supply is defective. Remove the
existing power supply and install a new one.
If the breaker does not trip, reinstall the circuit cards one-at-a-time
until the breaker trips.
Planning, Installation, Fault Clearing and CCBR Guide
Figures 56 and 57.
Page 471 of 536