HP EliteBook 8540P Maintenance And Service Guide

Ambient light sensor
NOTE: If it has been determined that the ambient light sensor is the component that must be
replaced to complete the computer repair, the display assembly does not have to be removed. Follow
the procedures in this section to replace the ambient light sensor. For information on replacing the
display assembly and the display hinges, see
Display assembly on page 82.
Description Spare part number
Ambient light sensor board (includes cable) 595781-001
Before removing the ambient light sensor, 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 47).
Remove the ambient light sensor:
1. Turn the computer right-side up, with the front toward you.
2. Open the computer as far as possible.
3. Remove the two rubber screw covers (1) on the bottom edge of the display bezel.
4. Remove the two Phillips PM2.5×5.0 screws (2) that secure the display bezel bottom edge to the
display assembly.
5. Flex the inside edges of the left and right sides (1) and the display bezel bottom edge (2) until
the bezel disengages from the display assembly.
52 Chapter 4 Removal and replacement procedures

HP EliteBook 8540P Specifications

General

Bus type	DMI
Stepping	K0
Tjunction	105 °C
Processor cache	4 MB
Processor cores	2
Processor model	i7-640M
System bus rate	2.5 GT/s
Processor family	Intel® Core™ i7
Processor series	Intel Core i7-600 Mobile Series
Processor socket	BGA 1288
Processor threads	4
Processor codename	Arrandale
Processing Die size	81 mm²
Processor frequency	2.8 GHz
Processor cache type	Smart Cache
Processor lithography	32 nm
Processor manufacturer	Intel
PCI Express slots version	2.0
Processor boost frequency	3.46 GHz
Processor operating modes	64-bit
ECC supported by processor	No
PCI Express configurations	1x16
Thermal Design Power (TDP)	35 W
CPU multiplier (bus/core ratio)	21
Maximum number of PCI Express lanes	16
Number of Processing Die Transistors	382 M
Motherboard chipset	Intel® QM57 Express
HDD speed	7200 RPM
HDD interface	SATA
Optical drive type	-
Card reader integrated	Yes
Total storage capacity	320 GB
Number of HDDs installed	1
Display diagonal	15.6 \
Display resolution	1600 x 900 pixels
Native aspect ratio	16:9
Modem speed	56 Kbit/s
Power supply type	AC/DC
Intel segment tagging	Enterprise
Compliance industry standards	IEEE802.3, IEEE802.3u, IEEE802.3ab
Internal memory	4 GB
Memory clock speed	1333 MHz
Internal memory type	DDR3-SDRAM
Maximum internal memory	8 GB
On-board graphics card model	Intel® HD Graphics
On-board graphics card base frequency	500 MHz
On-board graphics card dynamic frequency (max)	766 MHz
Pointing device	Touchpad
Wi-Fi standards	802.11a, 802.11b, 802.11g
Bluetooth version	2.1+EDR
Cabling technology	10/100/1000Base-T(X)
Networking features	Gigabit Ethernet
Operating system installed	Windows 7 Professional
Charging port type	DC-in jack
USB 2.0 ports quantity	USB 2.0 ports have a data transmission speed of 480 Mbps, and are backwards compatible with USB 1.1 ports. You can connect all kinds of peripheral devices to them.
CardBus PCMCIA slots quantity	0
AC adapter power	90 W
Battery capacity	73 Wh
Number of battery cells	8
Product color	Black, Silver
Country of origin	China
Processor code	SLBTN
Processor ARK ID	49666
Processor package size	rPGA 37.5x 37.5, BGA 34x28 mm
Graphics & IMC lithography	45 nm
Supported instruction sets	SSE4.1/4.2
Intel® Turbo Boost Technology	1.0
Physical Address Extension (PAE)	36 bit

Weight and Dimensions

Depth	252 mm
Width	374 mm
Height	32 mm
Weight	2950 g