Lenovo 7844B4U User Manual page 33

6. Remove the four screws that secure the heat sink and fan assembly in the
following sequence:
Note: Carefully remove the four screws from the system board to avoid any
possible damage. The four screws are integrated parts of the heat sink
and fan assembly and they cannot be removed from the heat sink and
fan assembly.
a. Loosen screw 1 , then completely remove screw 3 from the system
board, and then completely remove screw 1 from the system board, as
shown in Figure 19.
b. Loosen screw 2 , then completely remove screw 4 from the system
board, and then completely remove screw 2 from the system board, as
shown in Figure 19.
Figure 19. Screws that secure the heat sink and fan assembly
7. Lift the 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. When handling the heat sink and fan assembly, do not touch the thermal
grease on the bottom of the heat sink and fan assembly.
8. Place the new heat sink and fan assembly on the system board so that the
four screws are aligned with the corresponding holes in the system board.
Make sure that you properly place the new heat sink and fan assembly so that
you can easily connect the new heat sink and fan assembly cable to the
microprocessor fan connector on the system board.
9. Install the four screws in the following sequence to secure the new heat sink
and fan assembly in place:
a. Tighten screw 1 a small amount, then fully install screw 3 , and then
fully install screw 1 , as shown in Figure 19.
Chapter 2. Installing or replacing hardware
25