HP ProBook 450 G4 Notebook PC and HP ProBook 455 G4 Notebook PC - Maintenance and Service Guide
Fan
Description Spare part number
Fan 905774-001
NOTE: To properly ventilate the computer, allow at least 7.6 cm (3.0 in) of clearance on the left side of the
computer. 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 aected by
high external temperatures, system power consumption, power management/battery conservation
congurations, battery fast charging, and software requirements. Exhaust air is displaced through the
ventilation grill located on the left side of the computer.
Before removing the fan/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 battery (see Battery on page 66), and then remove the following components:
a. Service door (see Service door on page 33).
b. Hard drive (Hard drive on page 36)
c. Optical drive (Optical drive on page 34)
d. Keyboard (see Keyboard on page 45)
e. Top cover (see Top cover on page 52)
f. Battery (see Battery on page 66)
Remove the fan:
1. Position the computer upright on a at surface.
2. Disconnect the fan cable (1) from the system board.
3. Remove the cable from the clip on the side of the fan (2).
4. Remove the Phillips PM2.5×7.0 screw (3) that secures the fan to the computer.
70 Chapter 6 Removal and replacement procedures for Authorized Service Provider parts