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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.
Diagnostic LEDs
Instead of beep codes, errors are indicated via the bicolor Battery Charge/Status LED. A specific blink pattern is followed by
flashing a pattern of flashes in amber, followed by white. The pattern then repeats.
The diagnostic pattern will consist of a two-digit number being represented by a first group of LED blinks (1 through 9) in
amber, followed by a 1.5 second pause with the LED off, and then a second group of LED blinks (1 through 9) in white. This is
then followed by a three second pause, with the LED off, before repeating over again. Each LED blink takes 1.5 seconds.
The system will not shutdown when displaying the Diagnostic Error Codes.
Diagnostic Error Codes will always supersede any other use of the LED. For instance, on laptops, battery codes for Low Battery
or Battery Failure situations will not be displayed when Diagnostic Error Codes are being displayed.
Table 10. Diagnostic LEDs
Blinking
Problem Description
Pattern
Amber White
2
1
CPU failure
2
2
System board failure (included BIOS corruption or ROM error)
2
3
No memory/RAM detected
2
4
Memory/RAM failure
2
5
Invalid memory installed
2
6
System board/Chipset error
2
7
LCD failure
2
8
LCD Power rail failure
3
1
CMOS battery failure
3
2
PCI or Video card/chip failure
3
3
BIOS Recovery Image not found
3
4
BIOS Recovery Image found but invalid
Suggested Resolution
Replace the system board.
Flash latest BIOS version. If problem
persists, replace the system board.
Confirm that the memory module is
installed properly. If problem persists,
replace the memory module.
Replace the memory module.
Replace the memory module.
Replace the system board.
Replace the LCD module.
Replace the system board.
Replace the RTS battery.
Replace the system board.
Flash latest BIOS version. If problem
persists, replace the system board.
Flash latest BIOS version. If problem
persists, replace the system board.
Troubleshooting
75
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