How to test a computer monitor that isn’t working

Nothing appears on the monitor? Fortunately, testing a monitor is one of the easiest steps in troubleshooting your computer.

By fully testing your monitor through a logical troubleshooting process, you can be sure your monitor is or is not working properly, and then take the necessary steps to get it up and running again.

Follow these easy troubleshooting steps to test your monitor.

How to test a computer monitor that isn’t working

Time Required: Testing a monitor can take anywhere from a few minutes to much longer, depending on the cause of the problem.

  1. Check that the monitor is on! Some monitors have more than one power button or switch; make sure they are all on.
  2. Check for disconnected monitor power cord connections. The monitor may be working fine and your only problem is that the monitor’s power cord is loose or unplugged. Also be sure to check for any cable adapters that are not fully secured, such as a small connector that joins an HDMI or DVI cable to a VGA plug, or vice versa.

    A disconnected monitor power cable could be the cause of your problem if the monitor’s power light is completely off.

  3. Check for disconnected monitor data cable connections. Once again, the monitor may turn on without a problem, but no information can get to it because the cable connecting the monitor to the computer is disconnected or loose.

    A disconnected monitor data cable could be the cause of your problem if your monitor’s power light is on but is amber or yellow instead of green.

  4. Fully turn up the monitor’s brightness and contrast settings. The monitor may be showing information, but you can’t see it because the screen settings are too dark.

    Most monitors today have a single on-screen interface for all settings, including brightness and contrast. If it turns out that your monitor isn’t working at all, you probably don’t have access to this interface. An older monitor may have manual controls to adjust these settings.

  5. Check that your computer is working properly by connecting a different monitor than yours to make sure it works properly on your PC. The monitor may be working properly, but the computer may not be sending information to it. If the new monitor you have connected does not show anything either, go to step 6.
  6. If the new monitor you connected displays information from your computer, go to step 7.

    When testing your new monitor, be sure to use the data cable that came with it and not the one from the original monitor.

  7. Determine why the computer is not sending information to the monitor. Since neither monitor is working, you already know that the computer is not sending information to the monitor. In other words, you have shown that your computer, not the monitor, is the reason why nothing appears on the monitor. Chances are your original monitor is working fine, but something else is to blame, like a disconnected or faulty video card, for example.
  8. Test your original monitor with a monitor data cable that you know is working . The monitor may be working properly, but it cannot receive information from the computer because the cable connecting the monitor to the PC is no longer working.

    If possible, try using the monitor data cable you successfully tested with in step 5. If not, purchase a replacement monitor data cable to test with. The data cable on some older monitors is permanently attached to the monitor and is not replaceable. In these cases, you will need to skip this step and continue with step 8.

  9. If nothing else works, replace the monitor.

    A computer monitor is not a device that can be accessed by the user. In other words, don’t open the monitor and try to fix it yourself. If you prefer to have your dead monitor serviced rather than replaced, please have it done by a professional.

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  10. If even that didn’t work, you may not have had a problem with the monitor, but instead there may be a problem with the rest of the computer system. As mentioned in step 7 above, it’s probably time to find out why nothing is being sent to the monitor.