Service Manual

When you notice screen abnormalities like flickering, distortion, clarity issues, fuzzy or blurry image, horizontal or vertical lines,
color fade etc., it is always a good practice to isolate the LCD (screen) by running the Built-In Self Test (BIST).
How to invoke LCD BIST Test
1. Power off the Dell laptop.
2. Disconnect any peripherals that are connected to the laptop. Connect only the AC adapter (charger) to the laptop.
3. Ensure that the LCD (screen) is clean (no dust particles on the surface of the screen).
4. Press and hold D key and Power on the laptop to enter LCD built-in self test (BIST) mode. Continue to hold the D key, until
you see color bars on the LCD (screen).
5. The screen will display multiple color bars and change colors on the entire screen to red, green, and blue.
6. Carefully inspect the screen for abnormalities.
7. Press Esc key to exit.
NOTE: Dell SupportAssist Pre-boot diagnostics upon launch, initiates an LCD BIST first, expecting a user intervention
confirm functionality of the LCD.
Dell SupportAssist Pre-boot System Performance
Check diagnostics
About this task
SupportAssist diagnostics (also known as system diagnostics) performs a complete check of your hardware. The Dell
SupportAssist Pre-boot System Performance Check diagnostics is embedded with the BIOS and is launched by the BIOS
internally. The embedded system diagnostics provides a set of options for particular devices or device groups allowing you to:
● Run tests automatically or in an interactive mode
● Repeat tests
● Display or save test results
● Run thorough tests to introduce additional test options to provide extra information about the failed device(s)
● View status messages that inform you if tests are completed successfully
● View error messages that inform you of problems encountered during testing
NOTE:
Some tests for specific devices require user interaction. Always ensure that you are present at the computer
terminal when the diagnostic tests are performed.
For more information, see Resolve Hardware Issues With Built-in and Online Diagnostics (SupportAssist ePSA, ePSA or PSA
Error Codes) .
Running the SupportAssist Pre-Boot System Performance Check
Steps
1. Turn on your computer.
2. As the computer boots, press the F12 key as the Dell logo appears.
3. On the boot menu screen, select the Diagnostics option.
4. Click the arrow at the bottom left corner.
Diagnostics front page is displayed.
5. Click the arrow in the lower-right corner to go to the page listing.
The items detected are listed.
6. To run a diagnostic test on a specific device, press Esc and click Yes to stop the diagnostic test.
7. Select the device from the left pane and click Run Tests.
8. If there are any issues, error codes are displayed.
Note the error code and validation number and contact Dell.
Troubleshooting
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