The top left corner of my LCD monitor is acting up. The pixels are colored red and green. Not completely on like a stuck pixel, but variably faded. It's a seemingly random distribution, centered on the corner and fading out after a centimeter. It's very light and unnoticeable - I just assumed it was a pixel defect.

What's confusing me is that the pattern changes depending on the image on the screen. While looking at SuperUser, I see absolutely nothing. On this page, I see a ~3cm triangle. On scifi, it's ordered into 2 segmented columns composed of squares - green on the left and red on the right.

I should note that the top left corner's actual image (not counting the fading) is the same for all of these - just the tabs+address bar of my browser. The pattern sometimes stays with the window - dragging it to the right moves the red&green pixels, although it quickly fades out relative to the distance. I say "sometimes" because certain patterns (scifi) will move, while others (keygenmusic) are stationary.

I'm running Linux, although I recall seeing similar things on Windows. I can confirm it's not the graphics card, as it didn't show up on screenshot.

What's causing this?

  • Would you be able to take a picture of it? That does sound strange. – kobaltz Dec 31 '11 at 7:42
  • @kobaltz I might be able to get one later, although I'm not sure if the patterns will show up. – Pubby Dec 31 '11 at 7:45
  • I was thinking it sounds like it might be dryout of the light valves (LCD) Possible tiny crack or something. Shine a light through? try on a different computer? use different connection type (vga) to test if it changes? do a quick check at a very low res, with different single color desktops, or a monitor checker software. – Psycogeek Dec 31 '11 at 9:54
  • tiny monitor checking thing mediafire.com/?4sdarrxd59tqszc (montest 44k) does little to nothing, push some keyboard buttons (arrows RGB), changes colors so you can have single color quick to check, works ONLY in Windows systems. Something behind there putting pressure on the back of the pannel? slightly bent pannel frame. Any (odd) heat that might be there, from components (that dont usually exist there) – Psycogeek Dec 31 '11 at 10:25

If you can capture the effect using a screen shot program then it is likely a graphics card problem, if that doesn't work and you have to use a camera then it is likely a problem with the monitor.

I have a monitor that overheats and causes a strange collection of visual artifacts and the first step for me was to work out if it was the computer or monitor that was causing the problem. The problem is similar to yours in that the type of artifacts vary depending on what the monitor is displaying, ranging from full screen stuttering to white lines to half the screen appearing "dead" and changing the picture on screen by going between applications would recover from one set of artifacts to a different set.

In my case cooling the monitor using a desk fan pointed at the monitor eliminates the problem and has allowed me to continue to use it while I find a replacement.

Monitors do have complicated digital signal processors in them and this could be a sign that the monitor is starting to fail but in your case you still need to work out whether it is in fact the monitor or graphics card causing the problem. I would not expect it to be the graphics card, but you need to be sure.

  • It's not the graphics card. I'll try the fan later and see if that works. – Pubby Dec 31 '11 at 9:30

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