Lenovo Think station 4223 User Manual page 56

CAUTION:
The heat sink and fan assembly might be very hot. Turn off the computer and wait three to five
minutes to let the computer cool before removing 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" on page 30.
3. Lay the computer on its side for easier access to the system board.
4. Locate the heat sink and fan assembly you want to replace. Your computer have two heat sink and fan
assemblies. See "Locating parts on the system board" on page 10.
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" on page 10.
6. Follow this sequence to remove the four screws that secure each 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 28. 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 two new heat sink and fan assemblies in a way that the fans are toward the rear of the
computer. Align the four screws on each heat sink and fan assembly with the holes on the system board.
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ThinkStation User Guide
1 , then fully remove screw
3 , then fully remove screw
2 , and then fully remove screw
4 , and then fully remove screw
1 .
3 .