NEC POWERMATE PROFESSIONAL 9000 Service Manual page 157

3-4 Option Installation
1. Turn off and unplug the system unit.
2. Disconnect the keyboard, mouse, monitor, and any other attached device (such as
speakers or a printer) from the rear of the system unit.
3. If you have a Kensington Security Standard connector or other chassis lock
securing the system, remove it.
Loosen the three cover screws on the rear of the system unit.
4.
5. Slide the cover back about one-half inch; if necessary, anchor one hand on the
rear of the system unit as you slide the cover.
WARNING: Before you remove a system unit
cover, turn off the power and unplug the system
power cable. Power is removed only when the
power cable is unplugged.
CAUTION: Electrostatic discharge can damage
computer components. Discharge static
electricity by touching a metal object before
removing the system unit cover.
Figure 3-2 Loosening Cover Screws