Nortel Networks 400 4.0 User Manual

Page of 382
332
Chapter 25 Replacing or installing a cooling fan
N0060612
N0060612
7
Test the direction of the fan exhaust air flow to determine if the fan is correctly installed. 
a
Hold a piece of paper or your hand close to the fan exhaust. A correctly installed fan blows 
air away from the main unit. 
b
If the fan exhaust air flow is incorrect, remove the cooling fan (see 
) and reinstall the fan in the correct orientation (this procedure). 
Removing an expansion unit fan
The BCM expansion unit comes either with one fan or a redundant fan set. The single-fan unit is 
not upgradeable.
To remove an expansion unit fan
1
Shut down the system (see 
2
Disconnect the fan power cable from the hub card.
3
Locate the screws that fasten the fan casing to the expansion unit back wall and remove them. 
Refer to 
4
Remove the four screws (or snap rivets) that hold the fan to the expansion unit.
5
Lift the failed fan out of the expansion unit.
Warning: Protect the hardware components against damage from electrostatic discharge. 
Always wear a grounded wrist strap before you handle components. Always place the 
components in a static-free container.
Note: If the unit has redundant fans, each fan has a connector on the hub board.