Nortel North American DMS-100, Instruction Manual

Page: 93 / 679

-6 Trouble locating and clearing procedures
297-8021-544 Standard 15.01 March 2003
Repairing and replacing NT3X90AF cooling units
(continued)
At the FSP
3 Locate the two fuses at the front of the cooling unit and check them all.
4
If one or both fuses blow, replace the blown fuses with new fuses.
5 Replace the air intake grill and filter assembly at the front of the cooling unit.
At the FSP
6 Turn OFF the FAN FAIL OVERRIDE switch.
7 Go to step 44.
8 Proceed as directed in the following table.
9 Power down at the PDC.
At the back of the cooling unit
10 Disconnect the lugs that connect the frame wiring to the cooling unit.
At the front of the cooling unit
11 Remove the screws that secure the side rail covers to the frame.
12 Remove the eight screws that secure the mounting flanges on the sides of the
cooling unit to the frame. To remove the screws, use a 5/16-inch ratchet and
extension.
13 Ease the cooling unit toward you and out of the frame.
14 Ease the replacement cooling unit into the frame.
WARNING
Incorrect fuse values
Use replacement fuses of the correct rating, or
damage to the equipment can result.
If the FAN FAIL lamp Do
darkened when you replaced the
fuses step 5
remained on when you replaced
the fuses step 8
If your company procedures Do
direct you to do repairs step 21
direct you to not do repairs step 9