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 44).

5.Remove the following components:

a.Hard drive (see Hard drive on page 50)

b.Optical drive (see Optical drive on page 46)

c.Keyboard (see Keyboard on page 60)

d.Switch cover (see Switch cover on page 65)

e.Display assembly (see Display assembly on page 68)

f.Top cover (see Top cover on page 74)

g.Fan (see Fan on page 79)

h.Heat sink (see Heat sink on page 81)

i.Speaker assembly (see Speaker assembly on page 87)

j.Modem module (see Modem module on page 63)

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 45)

●Memory module (see Memory modules on page 56)

●WLAN module (see WLAN module on page 64)

●WWAN module (see WWAN module on page 58)

●Processor (see Processor on page 84)

●Graphics card (see Graphics card on page 85)

●ExpressCard assembly (see ExpressCard assembly on page 92) Remove the system board:

1.Position the computer right-side up, with the front toward you.

Component replacement procedures 89