Nortel Networks BCM200/400 - Manual (Page 340)

340 Chapter 25 Replacing or installing a cooling fan
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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 “Removing a BCM200
cooling fan” on page 337 ) 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 “Performing a system shutdown” on page 239 ).
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
Figure 188 on page 341 and Figure 189 on page 341 .
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.