Dell Precision 420 - Manual (Page 82)

Removing the Computer Cover (Desktop Chassis)
1. Turn off your computer and peripherals, and make sure that you unplug the computer from its electrical outlet before you remove the
computer cover. Observe the Caution for Your Personal Safety and Protection of Your Equipment . Also observe the safety instructions
found in your System Information Guide.
2. If you have installed a padlock through the padlock ring on the back panel (see Figure 1), remove the padlock.
Figure 1. Padlock Installed (Desktop Chassis)
3. Locate the release buttons on the sides of the cover (see Figure 2 ).
4. From the front of the computer, press and hold the release buttons, and pivot the cover up toward you (see Figure 2 ).
5. Disengage the cover hooks that secure the cover to the front of the chassis, and lift the cover away.
Figure 2. Removing the Computer Cover (Desktop Chassis)
Replacing the Computer Cover (Desktop Chassis)
1. Check all cable connections, especially those that might have come loose during your work. Fold cables out of the way so that they do not
catch on the computer cover. Make sure cables are not routed over the drive cage —they will prevent the cover from closing properly.
2. Check to see that no tools or extra parts (including screws) are left inside the computer's chassis.
3. Facing the front of the computer, hold the cover at a slight angle as shown in Figure 3 .
4. Fit the three cover hooks into the rectangular slots on the chassis. (It might be helpful to look down into the chassis to verify that the hooks are
in place.)
5. Pivot the cover down toward the back of the computer and into position.
Make sure that the two release buttons click into place.
Figure 3. Replacing the Computer Cover (Desktop Chassis)
1 Padlock ring
1 Release button (two, one each side)
NOTE: The computer should be placed fully on a flat surface. It is difficult to align the cover if the front of the computer is hanging
over the edge of a table.