IBM 9080-M9S Manual page 126

Figure 103. Removing a memory module filler
4. Grasp the new memory module along its edges and align it with the slot.
Attention: Memory modules are keyed to prevent a memory module from being installed
incorrectly. Note the location of the key tab within the memory module connector before you
attempt to install the memory module.
5. Install the memory module by pushing it into slot until the tabs (A) lock into place as shown in the
following figure.
120 Power Systems: Removing and replacing parts in the 9080-M9S system