Dell OptiPlex GX400 - Manual (Page 17)

Power Supply
To access some of the components on the system board, you may need to rotate the system power supply out of the way.
1. Turn off the computer and peripherals, disconnect them from their electrical outlets, wait at least 5 seconds, and then remove the computer cover .
2. Make sure the AC power cable is disconnected from the AC power receptacle on the back of the power supply (see the following figure).
Rotating the Power Supply in a Chassis
3. Free the power supply from the securing tab by pressing the tab labeled "RELEASE." Then rotate the power supply upward until it locks in its extended
position.
When you have finished accessing components on the system board, rotate the power supply back to its original position until the release tab snaps into the
securing tab.
Front Panel
To remove the front panel, you first must remove the computer cover . With the cover removed, release the front panel by pressing the green front-panel
release button marked with the icon (see the following figure).
Removing the Front Panel
CAUTION: Before you perform this procedure, see " Safety First—For You and Your Computer ."
CAUTION: Before you perform this procedure, see " Safety First— For You and Your Computer ."