Symptoms
Dell Latitude 5420 computer may experience the internal display flickering issue while running in DC mode, and no device plug-in.
Cause
This issue is only seen in older BIOS versions.
Resolution
Download and Updated the BIOS to version 1.8.0 or later to resolve this issue.
Updating the latest BIOS version on the computer will help resolve the issue. To download and install the latest BIOS:
WARNING: Dell recommends disconnecting devices such as external hard drives, printers, scanners, and so on, before updating the BIOS.
WARNING: Dell laptops must have the battery that is installed and charged to at least 10% before you begin the BIOS update. Dell recommends connecting the laptop to AC power before proceeding with the update process.
NOTE: To learn more about updating the BIOS on a Dell computer, see the Dell knowledge base article Dell BIOS Updates.
NOTE: To install the BIOS, your user account must have administrator privileges.
Browse to https://www.dell.com/support/drivers.Identify your Dell computer.
Click Download & Install SupportAssist to auto-detect your Dell computer. Follow the on-screen instructions to install Dell SupportAssist. For more information, see the Dell knowledge base article Dell SupportAssist (formerly Dell System Detect): Overview and Common Questions.Enter the Service Tag of the laptop and click Search.Or, click Browse all products and select your Dell computer from the catalog.
Select the Operating System that is installed on the Dell computer.Under Category, select BIOS.Locate the latest System BIOS.Click Download and save the file to your computer.Open File Explorer and browse to the location where the downloaded file is saved.Double-click the BIOS setup file and follow the on-screen instructions to complete the installation process.
