Dell POWEREDGE C6105 Hardware Owner's Manual page 109

Figure 3-27. Removing and Installing the Mid-plane Holder
1 screw (8)
14 Remove the screws that secure the lower middle plane to the chassis.
Figure 3-28.
15 Disconnect all the cables from the lower middle plane. See Figure 5-9.
Note the routing of the cable underneath the tabs on the chassis as you
remove them from the system. You must route these cables properly
when you replace them to prevent the cables from being pinched or
crimped.
16 Lift the lower middle plane out of the chassis. See Figure 3-28.
2 mid-plane holder
Installing System Components | 109