IBM 704 - Manual (Page 169)

Removing Adapters
Removing Adapters
14
Attention: Expansion-slot covers must be installed on all
vacant slots. This maintains the electromagnetic emissions
characteristics of the system and ensures proper cooling of
system components.
To remove an adapter, do the following steps:
1. Remove the adapter:
Note: If you are removing a PCI adapter, the screw is on the
inside back of the server.
a. Disconnect the cables that are attached to the adapter that
you are removing.
b. Note the slot number of the adapter that you are removing.
Chapter 4. Installing Options 151