Lenovo ThinkStation 2551 Hardware Maintenance Manual page 149

3. 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 84.
4. Follow this sequence to remove the four screws that secure the heat sink and fan assembly to the
system board:
a. Partially remove screw
b. Partially remove screw
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 79. Screws that secure the heat sink and fan assembly
5. Lift the heat sink and fan assembly with the fan duct 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.
1
, then fully remove screw
3 , then fully remove screw
.
Chapter 11 Replacing FRUs (for machine types: 3688, 3690, 3691, 3693, and 3695)
2
, and then fully remove screw
4 , and then fully remove screw
1
.
3 .
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