Apple PC Compatibility Card (Installation) - Manual (Page 59)

6 If there are security screws on the vertical plate on the back of the computer, remove
them with a screwdriver.
7 Unplug the power cord from your computer.
8 Gently pull down on the wire handle and swing it out to unlock it from its storage
position. Then grasp the handle and gently pull the logic board out of the computer.
The vertical plate and the logic board to which it’s attached slide all the way
out of the computer.
Unplug the power
cord from the back
of the computer.
If there are security screws, remove both screws from the vertical plate.
59 Installing the PC Compatibility Card in a Modular Desktop Macintosh Computer