Follow the instructions to replace the base cover assembly.

Before you start, read Generic Safety and Compliance Notices and print the following instructions.

Notes: Do not remove the base cover assembly in the following situations. Otherwise, there might be a risk of short circuits.

• When your computer has the removable battery installed
• When your computer is connected to ac power

For access, do the following:

1. Disable the built-in battery. See Disable the built-in battery.
2. Turn off the computer and disconnect the computer from ac power and all connected cables.
3. Close the computer display and turn over the computer.

Tool needed: Philips head screwdriver

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.

Follow the instructions to replace the built-in battery.

Before you start, read Generic Safety and Compliance Notices and print the following instructions.

Important notices for replacing a battery

Attention: Lenovo has no responsibility for the performance or safety of unauthorized batteries, and provides no warranties for failures or damage arising out of their use.

The Vantage app provides an automatic battery diagnostic test that determines if the built-in battery is defective. A built-in battery should not be replaced unless this diagnostic test shows that the battery is defective. The only exception to this is if the built-in battery is physically damaged or a customer is reporting a possible safety issue.

If the Vantage app is not installed on the computer, the customer should download and install the program to diagnose the built-in battery, before replacing a non-physically damaged built-in battery. Note that the replacement of a physically damaged built-in battery is not covered by the warranty.

For access, do the following:

1. Disable Fast Start up and the built-in battery. See Before you replace any CRU.
2. Turn off the computer and disconnect the computer from ac power and all connected cables.
3. Close the computer display and turn over the computer.
4. Remove the base cover assembly. See Base cover assembly.

Tool needed: Philips head screwdriver

CAUTION:
Remove any foreign objects before reassembly.
Ensure that the base cover assembly is secured in place. Otherwise, the battery connection might fail.

Follow the instructions to replace the M.2 solid-state drive and M.2 solid-state drive bracket.

Before you start, read Generic Safety and Compliance Notices and print the following instructions.

Attention:

• If you replace a M.2 solid-state drive, you might need to install a new operating system. For details on how to install a new operating system, see How to install a Windows operating system?.

The M.2 solid-state drive is sensitive. Inappropriate handling might cause damage and permanent loss of data.

When handling the M.2 solid-state drive, remove or insert the M.2 solid-state drive horizontally. Otherwise the slot might get damaged.

When handling the M.2 solid-state drive, observe the following guidelines:

• Replace the M.2 solid-state drive only for repair. The M.2 solid-state drive is not designed for frequent changes or replacement.
• Before replacing the M.2 solid-state drive, make a backup copy of all the data that you want to keep.
• Do not apply pressure to the M.2 solid-state drive.
• Do not touch the contact edge or circuit board of the M.2 solid-state drive. Otherwise, the M.2 solid-state drive might get damaged.
• Do not subject the M.2 solid-state drive to physical shocks or vibration. Put the M.2 solid-state drive on a soft material, such as cloth, to absorb physical shocks.

1. Disable the built-in battery. See Disable the built-in battery.
2. Turn off the computer and disconnect the computer from ac power and all connected cables.
3. Close the computer display and turn over the computer.
4. Remove the base cover assembly. See Base cover assembly.

Tool needed: Philips head screwdriver