Lenovo ThinkCentre M77 1990 User Manual page 60

1. Turn off the computer and disconnect all power cords from electrical outlets.
2. Remove the computer cover. See "Removing the computer cover" on page 32.
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" on page 11.
5. Disconnect any cables that might prevent your access to the heat sink and fan assembly.
6. Disconnect the heat sink and fan assembly cable from the microprocessor fan connector on the system
board. See "Locating parts on the system board" on page 11.
1
7. Pivot the handle
the plastic retention bracket.
Figure 31. Removing the heat sink and fan assembly
8. 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. When handling the heat sink and fan assembly, do not touch the thermal grease on the bottom of it.
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ThinkCentre User Guide
to release the heat sink and fan assembly clamp and then disengage the clamp from