This section provides instructions on how to replace the heat sink and fan assembly.

CAUTION:

The heat sink might be very hot. Turn off the computer and wait three to five minutes to let the computer cool before opening the computer cover.

To replace the heat sink and fan assembly, do the following:

1. Turn off the computer and disconnect all power cords from electrical outlets.
2. Remove the computer cover. See "Removing the computer cover".
3. Lay the computer on its side for easier access to the system board.
4. Locate the heat sink and fan assembly. See "Locating parts on the system board".
5. Disconnect the heat sink and fan assembly cable from the microprocessor fan connector on the system board. See "Locating parts on the system board".
6. Follow this sequence to remove the four screws that secure the heat sink and fan assembly to the system board:
   a. Partially remove screw 1 , then fully remove screw 2 , and then fully remove screw 1.
   b. Partially remove screw 3 , then fully remove screw 4 , and then fully remove screw 3.
   
   Note: Carefully remove the four screws from the system board to avoid any possible damage to the system board. The four screws cannot be removed from the heat sink and fan assembly.

Figure 1. Removing the heat sink and fan assembly

7. Lift the failing heat sink and fan assembly off the system board.
   Notes:
   a. You might have to gently twist the heat sink and fan assembly to free it from the microprocessor.
   b. Do not touch the thermal grease while handling the heat sink and fan assembly.
8. Position the new heat sink and fan assembly on the system board so that the four screws are aligned with the holes on the system board.
   Note: Position the new heat sink and fan assembly so that the heat sink and fan assembly cable is toward the microprocessor fan connector on the system board.
9. Follow the following sequence to install the four screws to secure the new heat sink and fan assembly.
   Do not over-tighten the screws.
   a. Partially tighten screw 1 , then fully tighten screw 2 , and then fully tighten screw 1.
   b. Partially tighten screw 3 , then fully tighten screw 4 , and then fully tighten screw 3.
10. Connect the heat sink and fan assembly cable to the microprocessor fan connector on the system board. See "Locating parts on the system board".
11. To complete the installation or replacement, go to "Completing the parts replacement".