Nortel North American DMS-100 Instruction Manual page 85

Repairing and replacing NT3X90AB cooling units
17
18
Toggle switches
Inverter cards
DMS-100 Family NA100 Trouble Locating and Clearing Procedures Volume 2 of 2 LET0015 and up
Trouble locating and clearing procedures (continued)
Inspect the fans in the cooling unit. Determine how many fans work.
If
fans work correctly but FAN
FAIL lamp remains on
one fan does not work
both fans in the back row or all
three fans in the front row do not
work
Note 1: A complete row of fans that have faults indicates an inverter that
powers the row is at fault. The row of fans that have faults also indicates
a blown fuse on the PDC frame for the inverter that has faults.
Note 2: One fan that does not operate indicates a damaged wiring
harness, loose connections, or a fan that requires replacement.
Note 3: All fans that operate normally with a lit FAN FAIL lamp indicate a
air flow sensor that has faults.
Locate the toggle switches at the back right corner of each inverter card.
Note: The toggle switches are the ON/OFF power switches for the
inverters.
Do
step 49
step 29
step 18
1-69
(continued)