Dell OptiPlex 390 (Mid 2011) - Manual (Page 31)

Installing the Heat Sink and Processor
1. Insert the processor into the processor socket. Ensure the processor is
properly seated.
2. Lower the processor cover.
3. Press the release lever down and then move it inward to secure it with the
retention hook.
4. Place the heat sink assembly into the chassis.
5. Tighten the captive screws to secure the heat sink assembly to the system
board.
6. Connect the heat sink assembly cable to the system board.
7. Install the
cover .
8. Follow the procedures in After Working Inside Your Computer .
31