Apple Xserve Intel (Late 2006) DIY Procedure for Power Distribution Board - Manual (Page 8)

Xserve (Late 2006) Power Distribution Board Replacement Instructions 
Shift the backplane to the left (towards the enclosure side), in the direction of the arrow
shown, until it clears the four mushroom-shaped standoffs that hold the backplane in place.
Rotate the backplane up slightly from the logic board side (as shown), and carefully pull the
backplane up and toward the logic board to free it from the standoffs and four backplane
alignment slots in the enclosure. Be careful not to let any backplane components come into
contact with the standoffs or the enclosure as you remove the backplane.
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