IBM Power System 9040-MR9 Manual page 27

Figure 11. Partially sliding the system from the rack
e) Label and unplug the SAS cables from the rear of the disk drive backplane as shown in the
following figure.
Press in on the clip to release the cable. Hold the disk drive backplane while you remove the SAS
cables to prevent the disk drive backplane from tipping forward and out of the system.
System backplane for the 9040-MR9 13