HP ProBook 4545s Notebook PC Maintenance and Service Guide

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 for use in computers with discrete graphics 654310-001
Heat sink for use in computers with UMA graphics 654311-001
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 37).
5. Remove the following components:
a. Bottom door (see
Bottom door on page 38).
b. Metal heat shield (see
Metal heat shield on page 51).
c. Fan (see
Fan on page 53).
Remove the discrete heat sink:
1. Position the computer upside down with battery bay away from you.
2. To remove the discrete heat sink, loosen the six captive Phillips screws (1) in the order indicated
on the components, that secure the heat sink to the system board.
54 Chapter 4 Removal and replacement procedures