IBM Power System 9040-MR9 Manual page 25

CAUTION: To prevent damage to the SAS cables, you must unplug the SAS cables from the
rear of the disk drive backplane before fully removing the disk drive backplane.
a) Loosen the two screws (A) as shown in the following figure.
b) Loosen the two recessed screws (B) as shown in the following figure. Use a 4 mm ball-end hex
driver (130 mm long, IBM part number 02EA546) to loosen the screws.
Figure 9. Loosening the disk drive backplane screws
c) Grasp the disk drive backplane with two hands as indicated by the blue squares in the following
figure. Pull the disk drive backplane approximately 2.5 cm (1 in) straight out from the front of the
system.
If you pull the disk drive backplane with one hand, it might twist sideways.
System backplane for the 9040-MR9 11