HP PB 6460B LQ177AW#ABA, QS020US, QX760US, LJ540UT 14 LJ540UT#ABA Description Spare part number

Description	Spare part number
● For use in computers with WLAN, with WWAN, no vPro (4M)	646321-002
● For use in computers with vPro (8M), WLAN, and WWAN	646323-002
● For use in computers with vPro (8M), WLAN, WWAN, and USB 3.0 ports	646324-002
For use in computers with discrete graphics:
● For use in computers with WLAN, with WWAN, no vPro (4M)	646316-002
● For use in computers with vPro (8M), WLAN, WWAN, and 512-MB graphics	646318-002
● For use in computers with vPro (8M), WLAN, WWAN, and 1-GB graphics	646319-002
● For use in computers with vPro (8M), WLAN, WWAN, 1-GB graphics, and USB 3.0 ports	670124-001

Before removing the system board, 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 63).

5.Remove the following components:

a.Bottom door (see Bottom door on page 70).

b.Hard drive (see Hard drive on page 76)

c.Optical drive (see Optical drive on page 72)

d.Fan (see Fan on page 90)

e.Heat sink (see Heat sink on page 91)

f.Keyboard (see Keyboard on page 96)

g.Bottom cover (see Bottom cover on page 98)

When replacing the system board, be sure that the following components are removed from the defective system board and installed on the replacement system board:

●SIM (see SIM on page 64)

●Memory module (see Memory modules on page 79)

●WLAN module (see WLAN module on page 83)

●WWAN module (see WWAN module on page 81)

●Modem module (see Modem module on page 89)

Component replacement procedures 117