User Guide

5. Clear the Turn on fast startup check box, and then click Save changes.
To disable the built-in battery:
1. Restart your computer. When the logo screen is displayed, immediately press F1 to enter the UEFI BIOS
menu.
2. Select Config ➙ Power. The Power submenu is displayed.
3. Select Disable Built-in Battery and press Enter.
4. Select Yes in the Setup Confirmation window. The built-in battery is disabled and the computer turns off
automatically. Wait three to five minutes to let the computer cool.
Replace a CRU
Follow the replacement procedure to replace a CRU.
Base cover assembly
Prerequisite
Before you start, read Appendix A “Important safety information” on page 71 and print the following
instructions.
Note: There might be a risk of short circuits if you remove the base cover assembly when your computer is
connected to ac power.
Replacement procedure
1. Disable the built-in battery. See “Disable Fast Startup and the built-in battery” on page 49.
2. Turn off the computer and disconnect the computer from ac power and all connected cables.
3. Close the computer display and turn the computer over.
4. Loosen the screws
1 , and then remove the base cover assembly 2 .
50 T490s and X390 User Guide