Lenovo ThinkCentre 3231 Hardware Maintenance Manual page 101

5. Remove the four screws 1 that secure the heat sink and fan assembly to the
system board.
Figure 10. Removing the heat sink and fan assembly
6. Lift the failing heat sink and fan assembly off the system board.
Note: You might have to gently twist the heat sink and fan assembly to free it
from the microprocessor.
7. Position the new heat sink and fan assembly on the plastic retention bracket so
that the four screws are aligned with the posts on the system board. Tighten
the four screws to secure the new heat sink and fan assembly to the system
board.
8. Connect the heat sink and fan assembly cable to the microprocessor fan
connector on the system board.
9. Go to "Completing the FRU replacement" on page 122.
Chapter 8. Replacing FRUs - Tower computers
95