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