Why does my computer monitor randomly turn off?
While there are many reasons why a computer monitor can turn off without warning, it usually has to do with power settings. For instance, many monitors have power-saving features that turn the monitor off if it doesn't receive input from the computer. Also, most operating systems allow users to adjust monitor sleep settings. That said, there are other contributing factors, such as loose cables, heat, and hardware issues.
The following sections contain suggestions and proposed solutions concerning computer monitors randomly turning off. To proceed, we suggest reading each section in the order presented.
If the monitor stays on but loses signal (e.g., the power light goes from green to orange), it's an issue with the computer and not the monitor. See: Why does my computer turn off without warning?
Loose cable
While it may seem obvious, if the power cord is not firmly connected to the monitor, it can cause issues with the flow of electricity. The interruption or total loss of power causes the monitor to turn off immediately. Check the monitor's power to ensure the cord is firmly and properly attached. It's also possible that the cable suppling power to the monitor is going bad. If the power cable is plugged in correctly and you still get power loss, we suggest replacing it.
Power settings
Most issues relating to monitors turning off unexpectedly involve power settings. We suggest looking at the power settings in your operating system to see if they're causing your monitor to sleep.
After reviewing that page, look through your monitor's menus to see if a setting is turning your display off or putting it to sleep.
Video card or motherboard problem
If the monitor stays on, but you lose the video signal intermittently, there could be an issue with the computer's video card. Look at the steps on the page below to verify your video card isn't causing the monitor troubles.
If the video card is working fine or your computer has integrated graphics, the motherboard may have problems. A bulged capacitor or other failing components on the motherboard can cause a computer to shut off and result in no signal to the monitor.
Monitor overheating
While less common with today's flat-panel displays, another reason monitors shut off is overheating. When a monitor exceeds a certain temperature, it turns off to prevent damage to the internal circuitry. Causes of overheating include excessive ambient temperatures, humidity, dust build-up, or other blockage of the vents that allow heat to escape.
If a monitor is overheating, unplug it and let it cool down fully before using it again. Then, if you have canned air (anti-static for electronics), try to blow out any dust inside the monitor casing. If the computer room is very hot, cool it down by turning on a fan or the air conditioning system. Wait until the room cools down before using the monitor again.
Also, if you're using an older CRT (cathode ray tube) monitor, upgrading to a newer flat-panel display resolves many heat-related issues in a hot environment.
Bad monitor
If none of the previous sections have explained or resolved your issue, your monitor has faulty hardware. There could be a short in the wiring or malfunctioning circuitry, causing the monitor to shut off or the screen to turn black. If you believe this to be the case, you can take the monitor to a computer repair shop to have it repaired. However, since the repair cost is often more than the price of a new monitor, replacement is usually the better choice.