How to Test a Computer Monitor that Isn’t Working
1. Check to make sure it is switched on! Some monitors have more than one power button or switch so you should always check first to make sure its switched on.
2. Check for disconnected power cable connections. Your monitor might be working fine and your only problem may be a loose or unplugged power cable.
Note: A disconnected power cable could be the cause of your problem if your power light is completely off.
3. Check for disconnected video cable connections. Again, your monitor might be turning on without a problem but no information can get to it because the cable that connects it to your computer is disconnected or loose.
Note: A disconnected video cable could be the cause of your problem if your power light is on but is amber or yellow instead of green.
4. Turn the monitor’s brightness and contrast settings completely up. Your screen might be sending a signal but it may not be visible simply because the 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 it 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, you should always make sure you use the video 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 it. In other words, you’ve proven that your computer is the reason that nothing shows up on your screen. Chances are your original monitor is working fine.
7. Test your original monitor with a video cable that you know is working. It may be possible that the monitor itself is working properly but it can’t receive information from the computer because the cable that connects it to the PC is no longer working.
Note: If possible, test using the video cable from the monitor that you successfully tested with in Step 5. If not, purchase a replacement cable to test with.
Note: The video cable on some older monitors are permanently connected and are not replaceable. In these cases, you’ll have to skip this step and proceed to Step
8. Replace the monitor.
WARNING: A computer monitor is not a user serviceable device. In other words you should not open it 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.