Before you start, read Generic Safety and Compliance Notices and print the following instructions.
Do not remove the base cover assembly when your computer is connected to ac power. Otherwise, there might be a risk of short circuits.
Disable the built-in battery. See Disable Fast Startup and the built-in battery.
Turn off the computer and disconnect the computer from ac power and all connected cables. Then, close the computer display.
Remove the nano-SIM-card tray if your computer comes with one. See Connect to a cellular network (for selected models).
Turn over 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.