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How To Test a Computer Monitor That Won't Display Or Is Not Working

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Is nothing showing up on your monitor? Luckily, testing a monitor is one of the easier computer troubleshooting steps.

By fully testing your monitor using a logical troubleshooting process, you can be confident that your monitor is or is not working properly and then take whatever action necessary to get back up and running.

Follow these easy troubleshooting steps to test your monitor.

Difficulty: Easy

Time Required: Testing a monitor could take from a few minutes to much longer depending on the cause of the problem

Here's How:

  1. Check to make sure your monitor is on! Some monitors have more than one power button or switch - check to make sure they're all switched on.

  2. Check for disconnected monitor power cable connections. Your monitor might be working fine and your only problem may be a loose or unplugged monitor power cable.

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

  3. Check for disconnected monitor data cable connections. Again, your monitor might be turning on without a problem but no information can get to it because the cable that connects your monitor to your computer is disconnected or loose.

    Note: 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. Turn the monitor's brightness and contrast settings completely up. Your monitor might be showing information but you just can't see it because these display settings are too dark.

    Note: Most monitors today have a single onscreen interface for all settings, including brightness and contrast. If it turns out that your monitor isn't working at all then you'll likely not have access to this interface. An older monitor might have manual knobs for adjusting these settings.

  5. Test that your computer is working correctly by connecting a different monitor that you are certain is working properly to your PC. Your monitor may be working fine but your computer might not be sending information to it.

    • If the new monitor you connected does not show anything either, proceed to Step 6.
    • If the new monitor you connected does show information from your computer, proceed to Step 7.

    Important: When testing with the new monitor, make sure you use the data cable that came with it and not the one from your original monitor.

  6. Determine why your computer isn't sending information to your monitor. Since neither monitor works, you now know that the computer is not sending information to the monitor. In other words, you've proven that your computer is the reason that nothing shows up on your monitor.

    Chances are your original monitor is working fine.

  7. Test your original monitor with a monitor data cable that you know is working. It's possible that the monitor itself is working properly but it can't receive information from the computer because the cable that connects the monitor to the PC is no longer working.

    Note: If possible, test using the data cable from the monitor that you successfully tested with in Step 5. If not, purchase a replacement monitor data cable to test with.

    Note: The data cable on some older monitors are permanently connected to the monitor and are not replaceable. In these cases, you'll have to skip this step and proceed to Step 8.

  8. Replace the monitor.

    WARNING: A computer monitor is not a user serviceable device. In other words - do not open the monitor and attempt to repair it yourself. If you would rather have your dead monitor serviced instead of replaced then please let a professional do it.

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