Heat sink assembly
NOTE: Only remove the heat sink from the system board if its removal is required to remove other
components. It is preferred to leave the heat sink connected to the system board when possible to preserve
the thermal materials used between the heat sink and system board. Removal of the heat sink requires
reapplication of this thermal material.
NOTE: The heat sink assembly spare part kit includes replacement thermal material.
Description Spare part number
Heat sink for use only in models with Nvidia Quadro graphics boards 850148-001
Heat sink for use only in models with the AMD FirePro graphics board 850149-001
Heat sink for use only in models with UMA graphics memory 850150-001
Before removing the heat sink assembly, follow these steps:
1. Turn o the computer. If you are unsure whether the computer is o 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 29).
5. Disconnect the battery (see Battery on page 31).
Remove the heat sink assembly:
1. On models with discrete graphics memory:
a. Following the (1) through (4) sequence stamped into the processor heat sink, loosen the four
Phillips captive screws that secure the processor heat sink to the system board.
b. Following the (5) through (8) sequence stamped into the graphics board heat sink, loosen the four
Phillips captive screws that secure the graphics board heat sink to the system board.
58 Chapter 6 Removal and replacement procedures for Authorized Service Provider parts