Maintenance and Service Guide

3. Remove the three Phillips PM3.0×4.5 screws (1) that secure the system board to the middle
frame.
4. Remove the system board (2).
Reverse this procedure to install the system board.
Heat sink
Description Spare part number
Heat sink (includes replacement thermal material) 728051-001
Before removing the heat sink, follow these steps:
1. Turn off the computer. If you are unsure whether the computer is off or in Hibernation, turn the
computer on, and then shut it down through the operating system.
2. Disconnect the power from the computer by unplugging the power cord from the computer.
3. Disconnect all external devices from the computer.
4. Remove the bottom cover (see
Bottom cover on page 23).
5. Remove the rear cover (see
Rear cover on page 26).
6. Disconnect the battery cable (see
Hard drive on page 27).
7. Remove the hard drive (see
Hard drive on page 27).
8. Remove the cover bracket (see
X-axis capacitor board on page 33).
9. Remove the display stand recess (see
Display stand recess on page 41).
10. Remove the fan (see
Fan on page 53).
11. Remove the system board (see
System board on page 54).
56 Chapter 4 Removal and replacement procedures