IBM Power System Series Manual page 150

Figure 124: Loosening the thumbscrews and removing the power midplane
d) Lift the power midplane by its bulkhead (C) and pull it out of the system. Refer to the previous
image.
e) Place the power midplane on an appropriate ESD surface.
20. Remove the system backplane.
a) Using a 5.5 mm Phillips head screwdriver, loosen but do not remove the four captive screws (A)
that mount the backplane to the chassis. Refer to the following image for the location of the
screws.
146 Power Systems: Temple's Zeppelin procedures for install, remove, replace