Lenovo ThinkCentre M90 3244 User Manual page 37

This section provides instructions on how to replace the heat sink.
CAUTION:
The heat sink might be very hot. Turn off the computer and wait three to five
minutes to let the computer cool before opening the computer cover.
To replace the heat sink, do the following:
1. Turn off the computer and disconnect all power cords from electrical outlets.
2. Open the computer cover. See "Opening the computer cover" on page 14.
3. Pivot the optical drive bay assembly upward. See "Accessing the system board
components and drives" on page 16.
4. Remove the hard disk drive to access the heat sink. See "Replacing the hard
disk drive" on page 22.
5. Carefully remove the four screws 1 that secure the heat sink to the system
board.
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.
Figure 24. Removing the heat sink
6. Carefully lift the heat sink off the system board.
Notes:
a. You might have to gently twist the heat sink to free it from the
microprocessor.
b. Do not touch the thermal grease while handling the heat sink.
7. Position the new heat sink on the system board so that the four screws are
aligned with the holes on the system board.
Chapter 2. Installing or replacing hardware
29