Ê Push in the FBU until it locks in place.
Ê Ensure that the FBU is properly seated in the holder as shown.
Figure 120: Position of the shoulder screw caps
Figure 121: Installing the FBU with the holder
Ê Insert the holder into the chassis so that the three shoulder screw caps on 
the chassis floor rest in the wide ends of the keyhole slots on the holder.
Ê Slide the holder in direction of the arrow.
The shoulder screw caps on the chassis floor will lock in the narrow ends of 
the keyhole slots on the holder.