How to check the screen for broken pixels

Trust but verify: testing your TV set before buying

It would seem that to choose and buy a TV set, what can be easier?? The modern market of home appliances offers an incredibly large range. But how not to miscalculate and buy a quality device? This is a technically complicated product, it is often not easy to return it to the seller, and some defects of the screen are not even considered a defect. Here’s how to properly test your TV without taking it out of the store.

To avoid buying a pig in a poke, you should get ready for the purchase at home. And it’s not just about browsing the many online resources. The presence of good reviews of the model indicates only that their authors had a successful copy. Nevertheless, a certain percentage of defects is present even at the most reputable manufacturers. Yes, and not every seller will be willing to test the device for the buyer. Therefore, even after deciding on a model, first of all we need to arm ourselves with knowledge of how to check the TV before buying it.

How to find and repair dead pixels on your notebook or PC monitor

Normal work on the computer involves the dynamic mixing of colors on the monitor, so it is quite difficult to notice a clear discrepancy. But sometimes for a while you can observe a monochrome screen, where you can clearly see all its flaws. dirt, dust, stains of unknown origin.

As a rule, these contaminants are easily removed by wiping with a special cleaner. If after such a general cleaning there are dots on the monitor that are different in color from the surroundings, we can assume that these are broken pixels. How dangerous it is and whether it can be dealt with independently, we today and tell our readers.

How many dead pixels are allowed on the matrix

Even if you have tested the monitor for dead pixels and found the problem, the seller has the right to refuse a return. The fact that there are norms that allow the presence of non-working elements on the display. The ISO13406-2 standard has been developed for this purpose, clearly specifying the number of. It all depends first of all on the class of the product:

Therefore, it is better to do a check for broken pixels in the store, rather than at home. Then you can simply refuse to buy and look for another model, the store. The detected defect after the purchase will be more difficult to arrange, you will have to go to the examination, to find out the cause of the breakage.

How to check a monitor for dead pixels

Checking the monitor for dead pixels is a task that requires a small amount of time and special tools that can quickly assess the condition of the matrix. We strongly advise you not to buy monitor without preliminary testing because there is always probability that the monitor is defective, even if you buy it from some premium brand, which has all sorts of regalia. Factory defects are something no one is immune to.

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The defective pixel is manifested by the fact that its color and luminous intensity does not change whatever picture is displayed on the monitor screen. Under dead pixels we often mean “dead” pixels. the points that do not work at all, they are easy to notice on a completely white background. In addition to these, other defects can occur for various reasons, which are often confused with broken pixels:

  • Hot pixels are pixels that show incorrect color due to excessive heating of the sensor. Usually they are bright red, green, blue or white dots, visible against a contrasting background.
  • Dependent pixels. in this case, the color and brightness of a dot will depend on the state of the pixels surrounding it. These are the hardest to spot, because they do change the character of the glow, depending on what image is now on the monitor.
  • Stuck pixels are those dots that always stay on because of a damaged transistor that continuously carries electricity to the RGB field. These pixels emit a certain color. red, blue or green under all conditions.

The good news is that sometimes defective pixels can be repaired, and in general they are not common, because modern matrix production is at a very high level, and the whole process is strictly controlled.

The bad news is that you can’t fix completely “dead” pixels and that’s why it’s crucial to check your monitor for dead pixels before buying. About this we will tell you further.

Response time and Hertzian speed of the monitor

In the TFT Monitor Test app select the moving square mode. You can use it to visually assess the performance of your monitor. Plus it will show you the average response time. In a nutshell, the blurring of the square in motion indicates a high response time. Lower is better.

About screen refresh rate, you need to plug your monitor properly and see how much is available. For example, on my HP Omen 27i monitor when I connect HDMI, only 144Hz is available. You must use DisplayPort 1 to get the claimed 165Hz.2.

Check your monitor for dead pixels (white, red, blue dots on the screen). How can I recover some broken pixels

Question from a user


I got a white dot in the middle and a red one in the corner. The one in the corner. I don’t care about it, but the one in the center. Sometimes it’s annoying and frustrating. When showing a color picture is not so noticeable, but with a monochrome (and especially dark). does not look good.

I was refused in the monitor repair, they say that these bit pixels can’t be repaired (it’s easier to buy a new monitor). Is it true and is there any way to remove these dots, to restore the broken pixels?

Check Your Screen for Dead Pixel/Stuck Pixel (up to 4K UHD) PixelFixel



In fact, one of the common problems with monitors is the appearance of dots on the screen that don’t change their color (t.е. don’t work). Most of the time they just glow the same color: white, dark, red, etc. Such pixels on the monitor are called broken pixels.

In this article I will try to answer both your question and the ones related to this topic. I’ll show you how to check your monitor for these bits and also give you some tips to bring these pixels back to life.

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#x1f4cc; Important!

Some users confuse dead pixels with ripples, bands and other image distortions on PC screen. If you have ripples and other artifacts. I recommend this article

Pour black on the monitor and a broken pixel looks like “in the palm of your hand”

Checking the monitor: doing a test to see if there are any broken pixels

A few important points

If you think that only old monitors have dead pixels, you’re way off. Even more offensive when you buy a new big monitor, and then in the process of work you find that one pixel in the center is not “lit” (or rather lit red). What’s more frustrating is that you probably won’t be able to get this monitor back under warranty!

According to the standard, monitors are divided into different classes (I, II and so on).). Each class is allowed a certain number of dead pixels and until the number is exceeded it’s not a warranty case!

So be very careful when you buy a new monitor, I recommend you test it directly in the store!

One of the tables with the allowable number of dead pixels is given below. Generally, IV. class is essentially a defect (and they are not on sale in the mass market), more often, the usual home monitor is a II or III class device.

So you need at least 2 or 3 dead pixels to get it back under warranty. My point is that checking when buying is very important!

How many dead pixels are allowed on a monitor (depending on its class). Important: This plate. this is just an example, the standards for discrepancies often change.

The essence of the test: you need to fill the screen in turns with different colors: white, red, green, black, etc. Whenever you pour, be sure to carefully look over the entire surface, to see if there is a point that stands out from the rest. See. The 2 pictures below show very well what to look for.

On a color picture a dead pixel is practically invisible!

But it is very well noticeable on a black (dark) background

The best way is to “fill” the monitor with different colors using special utilities. One of the most convenient is IsMyLcdOK (more about it below).

With the IsMyLcdOK program

One of the best utilities to check your monitor for dead pixels!

IsMyLcdOK. main program window. tips on the control buttons

It is very simple and you do not need to install or set up anything. It weighs only 36 KB and can be burned on any media. After starting the game you just need to press the numbers on your keyboard: 1, 2, 3, etc.д., or press the Ctrl key. and the whole screen will be successively filled with different colors. All you have to do is watch closely what happens.

So, using IsMyLcdOK you can evaluate monitor’s condition in few minutes. I recommend it as a must-have!

  • Small size. only 36 KB, you can write it on any flash drive;
  • No need to install or set up anything. Just start it and press a single Ctrl button;
  • It is free and works in all Windows versions.

Online method

Check the monitor can be and online way, but you need access to the Internet (not all stores can connect the tested PC / monitor to the network). In addition, another disadvantage of this method is that not the entire monitor is filled, but only the part that is shown in the browser (which is 90-95%, the stripes at the bottom and top are not filled).

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Otherwise it is the same effective way: the site address I gave above, clicking on the link you can run the test and click on the different colors. When the screen is filled with the right color. carefully review the entire surface, then fill again. After 3-4 iterations, it will already be possible to talk about the presence/absence of broken pixels.

When you need a test for dead pixels

When you buy a TV or monitor, you need to test for broken pixels. The examination helps to avoid the hassle of warranty service or replacement. To prove that the product can be returned, you will need to conduct an examination. And only after the matrix is checked for dead pixels and the presence of defects is confirmed, it is possible to speak about a malfunction. But this is not a guarantee of exchange for a new device, because the owner will have to prove that it was not his actions that caused the failure.

ISO13406-2 standards state that each monitor, may have a certain number of defective pixels when sold.

Different manufacturers have different standards for the presence of dead pixels depending on

For example, LG’s standards recognize the presence of 10 stuck and 3 “dead” pixels on the screen with a diagonal of 20 inches. Samsung’s standards call for 7 dead spots, while Dell’s are 6 stuck and 13 dead spots, depending on which display was found faulty. Therefore, even a pre-sale inspection of a Samsung screen for dead pixels, revealing a few dead pixels in acceptable quantities, is no big deal. But if you have more than one device, the test for dead pixels will allow you to choose the “healthiest” device.

Cases when you should refuse to buy. if the test for dead pixels revealed a deviation from the norms of the standard:

  • If the monitor or TV is assigned to class 4 (it can have up to 50 burning dots, 150 “dead” dots, 500 “stuck” dots),
  • If the monitor matrix is class 3 (this implies 5 “hot spots”, 15 “dead”, 50 “stuck”),
  • monitor’s quality class 2 means only 2 burning or “dead” pixels and only 5 “stuck” pixels,
  • If the monitor’s matrix is of the first class. there should be no discrepancies or defects at all on such goods.

Most common brands of monitors or screens are in the second class. They should also be checked for dead pixels. Inspection should reveal no more than 5 pixels that are not working correctly.

Visual inspection

This method will be especially relevant when the monitor is checked in a store, or is purchased out of hand and there is no possibility to use special software and online services.

This way of testing is quite simple in terms of implementation. Its essence is to display on the monitor monochrome images of several different colors. Namely:

These 5 colors are standard for this procedure. By displaying them and turning on full screen mode, you can detect with your own eyes possible broken, dead, burning or stuck pixels.

Preliminarily it is necessary to write down the corresponding images on USB flash drive and with it to come to the store or to the seller of the second-hand monitor.