Replacing Variable-Speed Fans; Replacing The Fan Power Filter - Avaya MCC1 Maintenance Procedures

Component replacement
Variable-speed fans
Alarm leads from each fan are tied together into a single lead that registers a minor alarm against
CABINET whenever a fan's speed drops below a preset limit or fails altogether.
NOTE:
The front fans may run at a different speed than the rear fans since they are controlled by
different sensors.

Replacing variable-speed fans

This procedure applies to replacement of a variable-speed fan (KS-23912, L3) in a new type fan assembly
(ED-67707-30, G4 or greater). Do not use a constant-speed fan in this assembly.
1 If replacing a fan in the front of the cabinet, remove the white plastic fan assembly cover by
pulling it outward. There is no cover on the rear fans; they are accessible simply by opening the
rear cabinet doors.
2 Connect the grounding wrist strap to yourself and the cabinet. The fan alarm circuit can be
damaged by ESD.
3 Disconnect the white 5-pin connector on the fan assembly.
4 Loosen and remove the retaining screw nearest the power connector on the defective fan.
5 Disconnect the 2-pin black power plug on the fan.
6 Loosen and remove the other retaining screw on the fan.
7 Remove the fan from the fan assembly.
8 Position the new fan and insert the screw that is opposite the power connector.
9 Connect the 2-pin black power plug on the fan.
10 Connect the white 5-pin connector on the fan assembly. Insert and tighten the retaining screws.
11 Replace the front fan cover, if removed.

Replacing the fan power filter

The fan power filter (ED-1E554-30) is a metal box located behind the fans on the right-hand cable trough
as you face the rear of the cabinet. It is absent with constant-speed fan assemblies.
CAUTION:
The fan power filter can be replaced without powering down the cabinet. To avoid
damage, you must use the following steps in the order shown. Note that the J2F/P2F
connectors on the power filter must not be connected whenever connecting or
disconnecting the J2/P2 connectors on the fan assembly.
1 Access the power filter through the rear cabinet doors.
2 Connect the grounding wrist strap to yourself and the cabinet. The fan alarm circuit can be
damaged by ESD.
CAUTION:
Failure to disconnect the J2F connector on the filter before the J2 connector on the fan
assembly can damage the fan alarm circuits.
276 Maintenance Procedures
December 2003