Dell Laptop Screen LCD Diagnostics

If your laptop screen is not displaying video properly, you need to run what is called the Built-in Self Test (BIST) to determine if there is a problem with the screen itself or some other issue that is preventing your LCD laptop from displaying an normal image. The BIST will help you isolate problems such as lines on the screen, fuzzy text and images or poor color resolution. This test is important, as it helps run diagnostics outside of the Operating System.If no video is being displayed on the screen, then you can try an external monitor to see if that works. This test, however, is to determine if there is a physical problem with the LCD screen or if this is a problem that can be corrected within software.

Run the BIST Test On Your Dell Laptop

To begin the BIST test, you should hold down the D key and press the power button. Release them both, and this should begin the BIST test. You should see two colored bars appear on the screen, then text asking if you saw them. Select NO to begin the test.

You will see several different screens displayed along with beeping and an error screen at the end. The error message is normal. During the test, you should be looking for the same symptoms you’re getting within Windows, such as lines on the LCD screen, poor color, etc.

If you do not see these problems, then the issue is likely with a bad Windows driver. You should visit the Dell support site and get the latest driver for your graphics card and update the system’s BIOS.

If you did see the same issues you experience within Windows, then you have a physical problem with the LCD screen and it will likely need to be replaced.

Read more of our Dell hardware troubleshooting articles.

Category: Dell

About the Author ()

David is a tech professional with over fifteen years of experience in the IT fields of hardware, software and system administration.

Comments (5)

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  1. Nat says:

    Hi Dave,

    Thanks a lot for your feedback here. I’m having an issue with my Dell latitude laptop display that I can’t seem to diagnose. The display has fuzzy lines in browsers and off-color generally (a spattering of pink and green pixels). I first checked to see if the poor color appeared prior to the loading of the operating system to determine if the problem was a software or hardware one, and when I went into the BiOS setup, the colors appeared off, suggesting that it’s a hardware issue. However, everything looks fine when I run the BIST test or use an external display. Any suggestions on what the problem could be?

    • Dave says:

      Sounds like a bad LCD screen based on the spattering of pixels and the fact that it looks fine on an external monitor.

  2. Jeff Tucker says:

    I seem to be having an issue with the backlight. I can faintly see an image of the window but I have to shine a flashlight on the screen to see it more clearly. If I am looking at the monitor from an arms length away I cannot see an image.

    Is this due to the monitor or the LED ribbon or LED control board?

  3. Russ says:

    My perfect e6400 latitude fell from a footstool about 15 inches onto the floor. Now the screen has a mostly white left one third, two thirds grey on the right side with a view colored vertical lines where they meet. I can’t operate anything except on off.

    I tried the BIST start by pressing FN and ON simultaneously. After about 1 minute the three blue lights (top just left of center) began a series of 3 flashes (together) along with 3 concurrent beeps. It repeated these three beeps and flashes three times; then played a series of quick notes up and down as the three lights flashed quickly in succession. This combination will go on as long as i leave it on.

    If I touch the screen I create waves along the vertical join of the two colors white and grey.

    Any possible diagnosis from that?

    Thank you.


    • Dave says:

      Hi Russ. I would try re-seating the RAM. The hard drive is screwed in, so that should be fine. But based on what you describe it sounds like the LCD panel was damaged. Post on our forums for more help.

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