Working inside the computer is
WARNING FOR YOUR PERSONAL SAFETY AND PROTECTION OF THE EQUIPMENT
Before starting to work on the computer, perform the following steps in the sequence indicated:
1.Turn off the computer and all peripherals.
2.Disconnect the computer, peripherals, and power supplies from their power sources. Also disconnect any telephone or telecommunication lines from the computer. Doing so reduces the potential for personal injury or shock.
3.Touch an unpainted metal surface on the com- puter chassis, such as the power supply, before touching anything inside the computer.
While you work, periodically touch an unpainted metal surface on the computer chas- sis to dissipate any static electricity that might harm internal components.
In addition, Dell recommends that you periodically review the safety instructions at the front of this guide.
Removing and Replacing the Computer Covers
To troubleshoot problems inside the computer, you need to remove one or both of the computer covers.
WARNING: The power supplies in this computer system produce high voltages and energy hazards, which can cause bodily harm. Only trained service technicians are authorized to remove the computer covers and access any of the components inside the computer.
WARNING: Due to high voltages and energy haz- ards, never operate the system without the covers installed.
Removing the Computer Covers
Use the following procedure to remove a computer cover:
1.Observe the Warning for Your Personal Safety and Protection of the Equipment described earlier in this chapter. Also observe the safety instructions at the front of this guide.
2.To remove a computer cover, turn the cover’s keylock on the back panel of the computer (see Figure
Figure 7-1. Keylocks on the Computer’s Back Panel
3.Loosen the three screws along the back edge of the cover (see Figure
4.Slide the cover toward the rear of the system an inch or so, grasp the top of the cover at both ends, and lift it straight away from the chassis.