Apple iMac G5, 20-inch - Manual (Page 115)

iMac G5 (20-inch) Take Apart - Midplane Assembly
Removing the Midplane Assembly
1. To access the midplane assembly you must first remove other service modules. This
procedure will show you how to remove and replace these modules. Note: As you
remove each module, set it aside, along with the screws for that module.
2. Ground yourself. Touch the metal surface (as shown below) on the inside of the
computer to discharge any static electricity.
Warning: Always discharge static electricity before you touch any parts or
install any components inside the computer. To avoid generating static
electricity, do not walk around the room until you have finished installing the
part and closed the computer.