HP ProBook 450 G4 Notebook PC and HP ProBook 455 G4 Notebook PC - Maintenance and Service Guide

Heat sink assembly
All heat sink assembly spare part kits include replacement thermal material.
Description Spare part number
Heat sink for use in models with discrete graphics 907364-001
Heat sink for use in models with UMA graphics 907359-001
Before removing the heat sink assembly, follow these steps:
1. Shut down 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 all external devices connected to the computer.
3. Disconnect the power from the computer by rst unplugging the power cord from the AC outlet, and
then unplugging the AC adapter from the computer.
4. Remove the following components:
a. Service door (see Service door on page 33).
b. Hard drive (see Hard drive on page 36)
c. Optical drive (Optical drive on page 34)
d. WLAN module (see WLAN/Bluetooth combo card on page 40)
e. WWAN module (see WWAN module on page 42)
f. Keyboard (see Keyboard on page 45)
g. Top cover (see Top cover on page 52)
h. Battery (see Battery on page 66)
i. System board (see System board on page 74)
Remove the heat sink assembly:
1. Position the system board upside-down.
2. Discrete models: In the order indicated on the heat sink, loosen the 6 captive Phillips screws (1)–(6)
that secure the heat sink to the system board.
Component replacement procedures 79