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Latitude E6440 screen darker on right side
Hello
I've searched on this condition, but haven't found what I think is a definitive answer. As of yesterday, I noticed that about the right 1/3rd of the screen on my trusty old E6440 is suddenly slightly darker than the rest. I'm attaching a screenshot, below. My laptop has the original FHD screen and is AMD/Intel.
This condition persists when running Windows or Linux, so isn't a driver or GPU issue, AFAICT. I'd also note that in some circumstances the line is only visible (to me, who's colorblind) on windows or portions of the screen that are of a particular shade, generally fairly light but not bright white or darker colors (where I can't really see it). I think this is a totally unimportant observation, but thought I'd put it out there. The screenshot I chose has an off-white background, where you can see the change very clearly.
The screen has always had some bleed at the bottom, but now I also see some very slight areas of darkness right at the bottom (looks like a couple of extremely low mountains on a flat horizon). One is directly below the vertical line that splits the lighter and darker parts of the screen, and the other is maybe midpoint between that and the right edge.
If I press with a decent amount of pressure on the bottom of the screen just around where it changes, I can make the darker area get brighter again (return the screen to uniform brightness).
My guess is this has to do with the LCD cable - either it's bad or needs reseating, maybe at the back of the screen. But could it be the screen itself? I don't think this model has a separate backlight or inverter. Something like an inverter may be build into the cable.
Anyway, looking for any advice before I pull it apart.
Thanks
filbert
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May 26th, 2023 13:00
AFAIK, I believe the display's self-test is purely internal, not taking a signal from the GPU. So, I believe that any fault seen on that test indicates a problem with the display.
JimDandy68
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May 26th, 2023 08:00
I cannot get photos to show up here, not sure why.
https://photos.app.goo.gl/eFYzudPC5Kx69yxt9
JimDandy68
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May 26th, 2023 08:00
filbert
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May 26th, 2023 08:00
Hold down the D key and press the power button to power up the laptop and run the LCD built-in self-test (BIST). That will run diagnostics on the display panel.
How to Run the LCD Built-in Self-Test on a Dell Laptop | Dell UK
filbert
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May 26th, 2023 09:00
If the display looks fairly normal in the self-test, but not when in normal operation, then you might have an issue with your GPU or possibly the cable.
Run Dell Diagnostics:
Immediately after pressing the power button to turn on the laptop (or after clicking the Reboot command), press and hold F12 to enter the One Time Boot Menu, select Diagnostics and press Enter. The Dell Diagnostics will test major hardware components. Choose to run the extended tests.
If you decide to reseat the display cable, follow the procedures in the Latitude E6440 Owner's Manual. Look on YouTube for videos showing disassembly of your model. But, be cautious with them, as some use steps or methods that are not appropriate. Use the videos to add to your understanding of what to do, but follow the steps in Dell's manual.
If the issue turns out to be the discrete AMD GPU, I believe it is not removable. It is soldered to the system board. The integrated graphics are of course part of the CPU. The CPU is removable, but likely not worth the expense of replacing in such an old laptop if that is the issue.
Whenever touching components or working inside a computer, wear a grounded wrist strap, also called anti-static wrist strap, ESD wrist strap, or ground bracelet. It's a cheap and sensible precaution. Rest the laptop on an anti-static mat or at least a reasonable alternative such as corrugated cardboard.
JimDandy68
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May 26th, 2023 09:00
@filbert, thanks. So, interesting. I only see those two little black shadows (the "low mountains") on the bottom during the self test. The screen otherwise looks entirely uniform in brightness, cycling through all of the colors. Although, I would say, all of the colors in the test are either primaries or pure white, and like I said, I can't see this darker area on either dark colors or pure white, when booted into an OS.
https://photos.app.goo.gl/R2SpZ2EiBXufRhgh8
JimDandy68
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May 26th, 2023 12:00
It did appear during the self-test, but as when booted in an OS, it's only visible in areas that are in a certain range of colors
JimDandy68
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May 26th, 2023 12:00
@filbert, everything passes in diagnostics, but I do see that darker area on some screens. It all depends on the colors that are being displayed.
So I'm left thinking this is a cable issue (connection or cable itself). Thoughts on that? Thanks
filbert
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May 26th, 2023 12:00
Oh. When you wrote that "screen otherwise looks entirely uniform in brightness", I thought that meant that the issue was mostly not present on the display self-test. If the issue occurred there, then there is a hardware problem with the display.
filbert
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May 26th, 2023 12:00
If the issue did not appear when running the display's self-test, but does appear in both Windows and Linux, then I would suspect cable or connection or GPU.
You could boot into BIOS to see if the issue occurs there. I suspect that it will. And if you have access to an external monitor, you could connect it to see if the issue is visible on it. I suspect that it will be.
JimDandy68
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May 26th, 2023 13:00
Thanks for the help
JimDandy68
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May 26th, 2023 13:00
@filbert, so you're saying that from what I've described (seeing the issue during the self-test), you deduce it's not an issue with the cable, but the screen itself?