I will be buying a second hand monitor, a Benq LED Benq 24 V2420H FullHD.

What methods can I use to test that the monitor is OK. I mean like dead pixels etc.?

  • nice question. +1
    – kokbira
    Jul 7, 2011 at 18:14

1 Answer 1


Best way I can think of is show a fullscreen completely white image. Try to get the contrast on the monitor up a bit, then the dead pixels should stick out like a sore thumb.

Check out: http://jasonfarrell.com/misc/deadpixeltest.php

For stuck pixels: http://www.gdargaud.net/Hack/DeadPixels.html

  • 2
    While this is true for dead pixels, it may not reveal stuck pixels. So in addition to white, several other colors or combinations. I for example have a stuck pixel which shows fine on each of the tests but is obvious on the title bar of any program.
    – AndrejaKo
    Jul 7, 2011 at 15:27
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    I'd only add that you can crank up brightness a bit, as stores tend to be rather bright, and then cycle through several different solid background colors. Make sure to set the taskbar (if in windows) to auto hide so you get the bottom edge checked as well. Most stores with tech departments (Fry's Service Department, Best Buy Geek Squad) should allow you to open the monitor you're planning on buying and connect it to one of their computers for this testing. Jul 7, 2011 at 15:42
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    Also, while the store will generally not have an issue returning devices with dead/stuck pixels, most manufacturers have different definitions of how many stuck or dead pixels are necessary before the screen counts as defective. BeHardware had an article regarding this. The site reported some sort of SQL error first time I accessed it, but it loaded OK on refresh. behardware.com/articles/666-1/a-look-into-dead-pixels-2007.html Jul 7, 2011 at 15:48
  • It's also worth nothing to test the actual settings of the screen. The buttons on the bottom, do they work?
    – n0pe
    Jul 7, 2011 at 15:50
  • I use a lot of colors. In my LCD, dead pixels are more apparent with black screen.
    – kokbira
    Jul 7, 2011 at 18:16

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