Dell OptiPlex 990 (Early 2011) - Manual (Page 37)

Power Supply
14
Removing the Power Supply
1. Follow the procedures in Before Working Inside Your Computer .
2. Remove the cover .
3. Remove the front bezel .
4. Remove the drive cage .
5. Remove the intrusion switch .
6. Remove the heat sink .
7. Disconnect the cables from the system board.
8. Remove the screw that secures the power supply to the chassis.
9. Remove the screws that secure the power supply to the chassis.
37