Apple PC Compatibility Card - Manual (Page 27)

27 Installing the Card in a Power Macintosh 7200, 7300, 7500, or 7600
Opening the computer
1 Shut down the computer and disconnect all cables from the computer, except for the
power cord.
Leave the computer plugged in for now, to ground it and protect its
components from static electricity damage.
2 If the security bar is installed, remove it by removing the screw under the front panel and
pressing the center of the bar.
First, remove the screw.
Then, press the security bar near
its center to release it from the computer.