6. Install the new base cover assembly in place
secured under the base cover assembly. Then, tighten the screws to secure the base cover assembly
7. Turn over the computer and reinstall the nano-SIM-card tray.
8. Connect the ac power adapter and all disconnected cables to the computer.
If the computer does not start up after you reinstall the base cover assembly, disconnect the ac power
adapter and then reconnect it to the computer.
Wireless WAN card (for selected models)
The following information is only for the computer with user-installable modules. Ensure that you use only a
Lenovo-authorized wireless module specifically tested for this computer model. Otherwise, the computer will
generate an error-code beep sequence when you turn on the computer.
Before you start, read Generic Safety and Compliance Notices and print the following instructions.
Attention: Do not touch the contact edge of the wireless WAN card. Otherwise, the wireless WAN card
might get damaged.
1. Disable the built-in battery. See "Disable the built-in battery" on page 25.
2. Turn off the computer and disconnect the computer from ac power and all connected cables. Then,
close the computer display.
3. Remove the nano-SIM-card tray if your computer comes with one.
4. Turn over the computer.
5. Remove the base cover assembly. See "Base cover assembly" on page 26.
. Ensure that the latches of the base cover assembly are