Dell OptiPlex 990 (Early 2011) - Manual (Page 27)

Installing The Heat Sink
1. Place the heat sink/fan assembly into the chassis.
2. Tighten the captive screws to secure the heat sink/fan assembly to the
system board.
3. Lower the heat sink/fan assembly.
4. Press the release lever down and then move it inward to secure it with the
fan retention hook.
5. Connect the heat sink/fan assembly cable to the system board.
6. Install the
drive cage .
7. Install the front bezel .
8. Install the cover .
9. Follow the procedures in After Working Inside Your Computer .
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