IBM 9080-M9S Manual page 448

Figure 380. Installing an adapter in a cassette for the 9080-M9S system
Note: Ensure that the adapter is secured in the adapter retainer channel.
9. Replace the top cover on the cassette.
a) Lower the top cover on the top of the cassette.
b) Slide the top cover in the direction that is shown in the following figure until it latches securely.
442 Power Systems: Removing and replacing parts in the 9080-M9S system