Nortel North American DMS-100 Instruction Manual page 88

1-72 Trouble locating and clearing procedures (continued)
Repairing and replacing NT3X90AB cooling units
50
51
52
53
54
55
56
57
58
59
At the PDC frame
60
At the FSP
61
62
63
297-8021-544 Standard 14.02 May 2001
Disconnect the wiring to one of the sensor switches. Note the position and
color of the wires.
If the FAN FAIL lamp
remained on when you discon-
nected the sensor wiring for the
air flow
did not remain on when you dis-
connected the sensor wiring for
the air flow
Note: A FAN FAIL lamp that turned OFF when you disconnected the
sensor wiring indicates a sensor switch that has faults.
Remove the defective sensor switch.
Attach the replacement sensor switch to the switch bracket. Secure the new
sensor in position with screws, nuts, and washers.
Reconnect the wiring to the sensor switch, as noted in step 50.
Repeat steps 50 to 53 to check all sensor switches.
If the FAN FAIL lamp
turns off
remains on
Ease the cooling unit completely back into the frame.
Insert the eight screws that secure the brackets to the sides of the cooling
unit. To insert the screws, use a 5/16-inch ratchet and extension.
Reinstall the side rail on the front of the frame.
Locate the toggle switch near the back right corner of each inverter card.
If the switches worked during this procedure, turn back ON the switches.
Inspect the fuses that power the inverter cards. Replace any blown fuses.
Replace the air intake grill and filter assembly at the front of the cooling unit.
If the FAN FAIL lamp
is off
is on
Turn OFF the FAN FAIL OVERRIDE switch on the FSP.
Go to step 79.
(continued)
Do
step 53
step 51
Do
step 55
step 78
Do
step 61
step 78