Our LCD displays are the most-used output device on our computing systems. In this video, you’ll learn about troubleshooting input sources, LCD projector bulbs, fuzzy images, burn-in, dead pixels, flashing screens, and more.
If you’ve ever turned on your computer but your screen is black or it gives a message that says no signal, then you’ll need to do a bit of troubleshooting to determine why that’s occurring. One of the first things you’ll probably want to try is also one of the most easiest. You’ll want to find out if the monitor really is connected properly.
You should check to make sure that the video cable between the computer and the monitor is connected and that the connections are pushed in completely. You’ll also want to check the power for the monitor and make sure that it’s getting the proper amount of power to be able to even turn on. This is a very common problem, and although it sounds almost patronizing to ask somebody if the monitor is actually plugged in, you’ll find that a great deal of the time, that’s exactly what the problem happens to be.
If all of those cables are properly connected, we can move on to the next step, which is to check the input selection on the monitor configuration. There may be multiple input types for this particular monitor. It may support HDMI and DisplayPort, VGA, DVI, and many multiples of those connections.
Many monitors will automatically determine where the signal is coming in, and they will switch themselves automatically to that input. But not every monitor performs that function, so you’ll want to check the monitor configuration and make sure that if you’re plugging in an HDMI cable that your monitor is configured to look for, signal from the HDMI port. If you can see a video signal but the screen is very, very dim, your problem could be with the brightness or the contrast. Most monitors have options to allow you to turn up and turn down those values. So it may be a simple configuration setting to get that brightness turned up so that you can see the display.
And if nothing seems to help this problem, it could potentially be a hardware problem with the monitor itself. So you may want to try moving this monitor to another computer and see if the problem still occurs. Or you might want to find a known good monitor and plug into this computer, and if you’re still having problems, you know the issue probably isn’t with the monitor hardware.
And you may be able to see information on the screen when you’re booting up. There may be bios messages that go by. You might even see a Windows splash screen.
But as soon as that splash screen disappears, the screen remains black. It could be that the configuration settings of the operating system are not set properly for the type of monitor that you’re using. So if you’re booting into Windows, you may want to try the Windows VGA mode, which you access by pressing the F8 key while the system is booting up. VGA mode is a generic mode that works with practically any monitor. So you know running in VGA mode should be one that is compatible with the monitor that you’re using.
If you’ve ever been in a conference room, you’ve probably seen these LCD projectors that are hanging from the ceiling or sitting on the table. And you’ll notice that they give a very bright display. They’re able to do this because inside of this very small device is a very bright metal halide bulb. That bulb gets very, very hot because it is putting out a lot of light. If you were to measure it, it gets around 1,000 degrees Celsius inside of that bulb.
Because these bulbs get so hot, you’ll notice that these projectors have fans inside that are constantly running. There are also temperature sensors inside of these projectors, and if they get too hot, the projector will shut down to avoid damaging that bulb. And if you gracefully power down this projector, you’ll notice that even though the light turns off, the fan will continue to run for a number of minutes. That’s because the projector is slowly cooling off that bulb to help prevent it from having any damage to the bulb itself. These bulbs are relatively expensive, so this entire process of cooling the bulb is to make sure that we don’t damage the bulb, and that the bulb stays active and working as long as possible.
With enough use, however, these bulbs will eventually fail, and you’ll need to swap the bulbs out. On many of these projectors, it’s a relatively modular process. They’re designed for the end user to be able to open up the projector, take out the old bulb, and replace it with a new bulb. If someone is going through the process of replacing the bulb, especially if these projectors are ceiling-mounted, you might want to spend some time cleaning all of the dust and replacing the air filters inside of these systems. This will ensure that you have plenty of cool air that is able to be pulled through this projector and is able to keep that bulb as cool as possible.
One of the things you’ll notice about LCD display specifications is they tell you exactly what the horizontal pixels and vertical pixels are for that display. That’s because those pixels never change. You will always have that number of pixels in the horizontal, and you will always have that number of pixels in the vertical.
We refer to these numbers of pixels on the display as the native resolution, and if you want this display to be as crisp and clear as possible, you will want to match that native resolution in the video settings of your operating system. If you set your computer’s video output to be different than the native resolution of the display, it will try to adjust the screen to fit into the resolution that you specified. But one of the things you’ll notice is that the text and the graphics will not be as crisp as you might expect.
This graphic shows us what the monitor looks like when you set the operating system to a resolution that is not compatible with that native resolution of the display. You’ll notice that some of the text is trying to adjust to that different size by expanding and contracting the size of the letters. And if you look at this overall on the display, it is certainly not as crisp and clear as if you had selected the native resolution.
If this is what your display looks like, you may want to try changing the display resolution in your operating system. If you don’t want to use the native resolution of the monitor. You could try a multiple of that native resolution to get the best possible output on that display screen.
If you ever look at a monitor that is always on and always displaying the same type of information, you’ll start to see information that is still on the screen even though the other information on the screen has already changed. You may see some ghosting or some background colors from information that previously used to be shown on that particular display.
We refer to this ghosting of information that is no longer being shown as burn in. That’s because the information that was displayed on the screen has been there for an extended period of time. Many monitors will try to prevent this from occurring by examining the information that’s being displayed on the screen. And if the monitor notices that not much on the screen is changing, it will slightly shift the image on the screen a few pixels in one direction or another.
This is in the hopes that it’s able to move the monitor just enough to prevent any type of burn in but not move the picture enough that you might notice. You may see this mentioned in the monitor configuration as pixel shift, and you may want to make sure that is turned on for your monitor. This was a much larger issue on the older style CRTs, or Cathode Ray Tubes. But these days, even LCD monitors have this particular issue.
On LCD monitors, you may hear this referred to as image sticking, and it might be possible to remove that image from the screen by putting a different image on the screen for an extended period. For example, you might want to display a white screen overnight just to see if you can remove that image sticking from your LCD monitor.
Here’s another view of this burn in or image sticking on a monitor. You’ll notice right at the top the screen used to say departures. Now it says departures all airlines. We know that it used to say departures because you can almost read the word departures that has been ghosted into the screen at the very top. And we can see similar problems with colors and other text that’s on the screen because it’s been displaying similar information over such an extended period of time.
These LCD displays consist of millions of pixels. So it is possible that one of those pixels might go bad. When that occurs, you have a dead pixel, which means that you have a pixel on the screen that is always going to be black.
This is probably a manufacturing defect, and it’s unlikely that you would be able to remove that dead pixel by replacing a cable or changing a display setting. Before you call the manufacturer to swap out this monitor, though, you might want to be sure that it really is a dead pixel. So make sure that the screen is clean and that you’re not just seeing a little bit of dirt that may have attached itself to the outside of the screen.
This is something you can’t fix inside of this monitor. It’s not possible to undo a dead pixel once this pixel has failed. So to resolve the problems of a dead pixel, you’ll need to replace the entire display.
It might be that the dead pixel is at the corner of the screen. You probably won’t even see it, and you may be able to work with that. But it seems more often than not that that pixel is somewhere that we always see it on the screen, and the only way to fix this is to get a new monitor.
There may be times when someone is working on their computer. They’re surfing the internet, working on a document, and everything is looking fine until suddenly, the screen goes black, and then suddenly, just as quickly, everything comes back. In that particular case of a flashing screen, there are a number of troubleshooting steps you can go through to determine why this screen is flashing.
One of the first things you’ll want to check is that the video cable connections are tight and that the cable itself is not loose or falling out of any of those connectors. Sometimes the cable itself is faulty, and if you swap out the video cable, you may be able to resolve the issue. The problem could be within the monitor hardware itself. So you may want to try swapping this monitor for a known good display and see if the problem still occurs.
And you might also want to look at the configuration settings of your operating system and that it is set to exactly the make and model of the monitor that you’re using. You might also want to look at the display configurations of your operating system, and make sure that those settings are compatible with the specifications of your monitor. When you’re using a monitor, you expect to have bright whites and colors that are very vibrant. But occasionally, you might get a monitor like this one, where the colors are not quite correct.
You’ll notice that they’re either too blue or too green, and none of the color representation matches what really should be shown on this display. The monitor itself has settings where you can define things like the tint. There may be custom color presets in the monitor configuration, and there may be a button to factory reset all of these settings so that you can take it back to a known good configuration.
The operating system also can set output controls for the color. So you may want to look at the color tint inside of your display settings and make sure that they are not skewed in one direction or another. Some operating systems have a night mode or a night light setting that dramatically changes the colors on the screen.
For example, during the nighttime, you may notice that the screen has more of a blue tint. If you’re someone who’s doing graphics design or video editing, that might cause problems when you’re using that device. So check your night mode settings inside of your operating system and see if you can toggle those settings on and off as you need them.
Many monitors we use today are for more than just video output. Many of these monitors have speakers inside of them, and we can use them as audio output as well. If you’re having a problem getting any sound out of the monitor or the volume levels are very low, you’ll probably want to do some troubleshooting.
If the monitor has speakers, then it probably also has a volume control setting. So you may want to check that volume control to see if it’s turned down or if someone may have muted the speakers entirely. We also might be getting the audio input from a number of different sources.
If the sound is being received over the same cable that’s being used for viewing, you might want to look at your monitor configuration and that the audio input matches the video input. So if you’re using an HDMI connection, make sure that your sound is also set for an HDMI input. You might also want to look at your operating system and confirm that it’s configured to send audio out the HDMI port as well. Some monitors also have other connections for audio. For example, your monitor might have an analog audio input. This means you may have to configure the monitor to accept video on HDMI, and accept audio on the analog audio input.
If the monitor is difficult to see, it could simply be that the display settings for brightness and contrast are not set properly. Most monitors will allow you to set those brightness controls, and that should be the first thing to check if you’re having a problem with a dim screen. You might also want to check your operating system. These days, many operating systems are said to modify the display output depending on the time of day or how much light is being received on that particular computer.
So you might want to check to see if there is an auto dimming function in the operating system, or if you’re running on a laptop and you unplug from a power source, it might naturally dim the display on the laptop just so you can conserve that much battery. And of course, the driver settings inside of that laptop or desktop computer may have settings for brightness as well. If you’ve made changes to these settings and the display is still very dim, the issue could be with the backlight of the display itself. This might be very obvious if part of the screen is very bright and other parts of the screen are very dark, and you’ll know that you’ve had a partial failure of the backlight. In some cases, you might be able to order parts to replace in that monitor that would enable the backlight again, or you’ll have to replace the entire monitor.
You’ve probably sat down at a computer and noticed that the display is not quite right. There might be flashing or flickering, or there might be bars that are extending across the screen. This might not be enough to completely prevent us from working, but it certainly doesn’t provide us with the best quality display.
If this is an analog connection, you might want to look at the pins on the connector and make sure that everything is plugging in properly to the interface. You might also want to check your operating system and see what the geometry settings are for this particular monitor and see if there might be any settings for resolution that might be more compatible with the display. A good rule of thumb is to set your computer to match the native display of the monitor to get the best possible screen. So you might want to change the operating system, at least temporarily, to see if making those changes have any effect on the quality of the screen.
And the issue may be related to the cable. So replacing the cable might be an easy check to see if that resolves this particular issue. Some video drivers support the ability to enable or disable hardware acceleration within the video card. This hardware acceleration is designed to give us the fastest possible updates to the screen, which increase the overall quality of the display output. But this hardware acceleration can also cause problems in certain configurations. So disabling the hardware acceleration might improve the overall quality of the image.
It can sometimes be a challenge to get a computer and a display to be completely compatible with each other. Fortunately, many operating systems will recognize any differences and try to adjust the image to give you the best quality output. But sometimes, these settings are disabled and you might get something like this, where the display itself is very small on a screen that is much larger.
Inside your operating system is probably a display setting for scaling, and if you enable scaling on that system, it will expand the image so that it fits the entire height and width of the monitor that you’re using. Another sizing issue you might run into is when you have a very high resolution monitor, and you’re running your operating system at the native resolution of that monitor. This commonly results in tiny little icons that are on the screen and text that is very difficult to read.
But there are configuration settings that allow you to change the scaling of the operating system so that you can keep the same resolution, but simply increase the scale of the text, the apps, and other items in the operating system. This means you can start with a scaling of 100% where you have a 4K display but very small icons on the screen. If you increase this to 200%, then you may be able to work with the user interface components much easier, and increasing to 300% allows you to really read what’s on the screen and makes all of these user interface components of the operating system work at a level that is comfortable to the end user.
Sometimes you’ll work with an LCD display that has flickering or flashing. There may be blocks of information on the screen, or lines that are going across the entire length of the screen. This makes it very difficult to see what’s on the screen and, in some cases, makes it so that you can’t see anything that you’re doing on that particular display.
If it’s an extensive problem, similar to the one that we see on the screen here, then it’s probably a hardware failure of the display. These liquid crystal displays are very easy to break, and you want to be sure that you don’t touch or put anything near that LCD screen. If you do run into this problem, then you’ll probably need to replace the entire display to resolve this issue.
Before you make any drastic changes, though, you might want to swap out the display cable and make sure that it’s not related to any connectivity between the computer and the display. And if you have a separate video adapter, you might want to try replacing that adapter and see if the problem disappears. And it might even be possible that this is a bad video driver, and by adjusting or changing the driver that you’re using, you may be able to resolve this problem.
Many technicians will use test patterns so that they can see exactly where on the screen there might be a problem. They can evaluate the sharpness of the screen and see if the color representation is what you might expect. Based on this evaluation, you may be able to decide whether this is a display that you’re able to fix or whether you need to replace the entire display.