Nortel North American DMS-100 Instruction Manual page 86

1-70 Trouble locating and clearing procedures (continued)
Repairing and replacing NT3X90AB cooling units
19
20
At the PDC frame
21
At the frame
22
23
24
25
26
At the PDC frame
27
At the frame
28
29
30
31
32
33
297-8021-544 Standard 14.02 May 2001
Cycle the toggle switches on both inverters until you find the inverter that
powers the row of fans that have faults.
Switch OFF the inverter that provides power to the row of fans that have
faults.
Remove the fuse for the damaged inverter.
Disconnect the connector at the back left corner of the inverter.
Use a pair of needle-nosed pliers to disconnect the four plastic mounting pins.
Lift the old inverter out of the cooling unit. Replace the old inverter with a new
inverter.
Mount the new inverter on the four plastic mounting pins.
Plug the connector into the back left corner of the inverter.
Examine the fuse to the inverter. If the fuse is a blown fuse, obtain a new fuse.
Replace the fuse in the PDC.
Turn ON the toggle switch of the new inverter.
If
the fans work normally and the
FAN FAIL lamp does not turn
on
other than listed here
To turn OFF the inverters, use the toggle switches at the back right corner of
the inverters.
Inspect the cooling unit wiring harness for damage and/or a loose connection
at the fans or terminal blocks.
Replace a defective harness. Tighten any loose connections.
To turn ON the inverters, use the toggle switches at the back right corner of
the inverters.
Inspect the fan operation.
If the fan
works correctly, but did not
work in step 17
(continued)
Do
step 55
step 78
Do
step 55