Dell Precision 490 - Manual (Page 131)

3. Rotate the card retention mechanism back into its original position; push its tip so that its tab clicks into place.
4. Reconnect both sides of the P3 power-cable bundle that is attached to the card retention mechanism.
Replacing the Front Panel
1. Align the hooks on the front panel with the corresponding holes on the front of the computer.
2. Pull the front-panel release lever, and slide the panel to the right to engage and secure the front panel.
Replacing the Computer Cover
1. Ensure that all cables are connected, and fold cables out of the way.
Gently pull the power cables toward you so that they do not get caught underneath the drives.
2. Ensure that no tools or extra parts are left inside the computer.
3. Replace the cover:
a. Align the computer cover with the tabs on the computer base.
b. Pivot the cover down and gently press the cover until it clicks into place.
c. Ensure that the cover is locked. If not, repeat all of step 3 .
2 card-retention mechanism
3 rotatable hard-drive carrier
1 front-panel release lever
2 front panel
NOTICE: The computer cooling system cannot function properly while the computer cover is not installed. Do not attempt to boot the computer before
replacing the computer cover.