Owners Manual

How to invoke L-BIST Test:
1. Press the power button to start the system.
2. If the system does not start up normally, look at the battery status LED:
● If the battery status LED flashes an error code [2,7], the display cable may not be connected properly.
● If the battery status LED flashes an error code [2,8], there is a failure on the LCD power rail of the system board, hence
there is no power supplied to the LCD.
3. For cases, when a [2,7] error code is shown, check to see if the display cable is properly connected.
4. For cases when a [2,8] error code is shown, replace the system board.
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 PC settings.
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
the system boots up.
5. The screen will display solid colors and change colors on the entire screen to white, black, red, green, and blue twice.
6. Then it will display 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 system will shut down.
NOTE:
Dell SupportAssist Pre-boot diagnostics upon launch, initiates an LCD BIST first, expecting a user intervention
confirm functionality of the LCD.
System diagnostic lights
Battery-status light
Indicates the power and battery-charge status.
Solid white—Power adapter is connected and the battery has more than 5 percent charge.
Amber—Computer is running on battery and the battery has less than 5 percent charge.
Off
● Power adapter is connected, and the battery is fully charged.
● Computer is running on battery, and the battery has more than 5 percent charge.
● Computer is in sleep state, hibernation, or turned off.
The power and battery-status light blinks amber along with beep codes indicating failures.
For example, the power and battery-status light blinks amber two times followed by a pause, and then blinks white three times
followed by a pause. This 2,3 pattern continues until the computer is turned off indicating no memory or RAM is detected.
The following table shows different power and battery-status light patterns and associated problems:
Table 18. LED codes
Diagnostic light codes Problem description
2,1 Processor failure
2,2 System board: BIOS or Read-Only Memory (ROM) failure
90 Troubleshooting