LCD Built-in Self-Test (BIST)
Dell laptops have a built-in diagnostic tool that helps you determine if the screen abnormality you are experiencing is an inherent
problem with the LCD (screen) of the Dell laptop or with the video card (GPU) and computer settings.
When you notice screen abnormalities like flickering, distortion, clarity issues, fuzzy or blurry image, horizontal or vertical lines,
color fade and so on, it is always a good practice to isolate the LCD (screen) by running the Built-In Self-Test (BIST).
How to invoke the LCD BIST
1. Turn off your computer.
2. Disconnect any peripherals that are connected to the computer. Connect only the AC adapter (charger) to the computer.
3. Ensure that the LCD (screen) is clean (no dust particles on the surface of the screen).
4. Press and hold the D key and press the power button to enter LCD built-in self-test (BIST) mode. Continue to hold the D
key until the computer boots up.
5. The screen displays solid colors and change colors on the entire screen to white, black, red, green, and blue twice.
6. Then it displays the colors white, black, and red.
7. Carefully inspect the screen for abnormalities (any lines, fuzzy color, or distortion on the screen).
8. At the end of the last solid color (red), the computer shuts down.
NOTE: Dell SupportAssist Preboot diagnostics upon launch initiates an LCD BIST first, expecting a user intervention to
confirm functionality of the LCD.
Diagnostic error codes
The Service LED is used for system diagnostics, and it emits amber or white light. A Dell service representative uses the LED
light patterns to troubleshoot your device.
NOTE:
An error code of 35 indicates an EC power-rail error. This may occur during POST (Power-On Self-Test). Contact
Dell Support for assistance.
Recovering the operating system
When your computer is unable to boot to the operating system even after repeated attempts, it automatically starts Dell
SupportAssist OS Recovery.
Dell SupportAssist OS Recovery is a stand-alone tool that is preinstalled in Dell computers running Windows operating system.
It consists of tools to diagnose and troubleshoot issues that may occur before your computer boots to the operating system. It
enables you to diagnose hardware issues, repair your computer, back up your files, or restore your computer to its factory state.
You can also download it from the Dell Support website to troubleshoot and fix your computer when it fails to boot into the
primary operating system due to software or hardware failures.
For more information about the Dell SupportAssist OS Recovery, see Dell SupportAssist OS Recovery User's Guide at
Serviceability Tools at the Dell Support Site. Click SupportAssist and then, click SupportAssist OS Recovery.
Real Time Clock—RTC reset
The Real Time Clock (RTC) reset function allows you or the service technician to recover the recently launched model Dell XPS
systems from No POST/No Boot/No Power situations. You can initiate the RTC reset on the system from a power-off state
only if it is connected to AC power. Press and hold the power button for 32 seconds. The system RTC reset occurs after you
release the power button.
NOTE:
If AC power is disconnected from the system during the process or the power button is held longer than 40
seconds, the RTC reset process gets aborted.
The RTC reset will reset the BIOS to Defaults, un-provision Intel vPro and reset the system date and time. The following items
are unaffected by the RTC reset:
● Service Tag
104
Troubleshooting
To Next Page
Loading...
