Dell OptiPlex 990 (Early 2011) - Manual (Page 29)

11. Lift the processor to remove it from the socket and place it in an antistatic
package.
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. Secure the Input/Output Board or the FlyWire cable to the routing channel
on the heat sink.
7. Connect the heat sink assembly cable to the system board.
8. Install the
drive cage .
9. Install the front bezel .
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