Specifications

The computer uses an electric fan for ventilation. The fan is controlled by a temperature sensor and is
designed to turn on automatically when high temperature conditions exist. These conditions are
affected by high external temperatures, system power consumption, power management/battery
conservation configurations, battery fast charging, and software requirements. Exhaust air is
displaced through the ventilation grill located on the left side of the computer.
Heat sink
All heat sink spare part kits include replacement thermal material.
Description Spare part number
Heat sink (does not include fan)
NOTE: If 639475-001 is not available, use 661525-001.
639475-001 or
661525-001
Before removing the heat sink, follow these steps:
1. Shut down 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 all external devices connected to the computer.
3. Disconnect the power from the computer by first unplugging the power cord from the AC outlet,
and then unplugging the AC adapter from the computer.
4. Remove the battery (see
Battery on page 49).
5. Remove the following components:
a. Remove the bottom cover (see
Bottom cover on page 51).
b. Fan (see
Fan on page 74).
Remove the heat sink:
1. Turn the computer upside-down, with the front toward you.
Component replacement procedures 75