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Faulty monitor or faulty VGA cable?

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#1 stebbinsd


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Posted 22 February 2018 - 08:00 AM

My desktop monitor currently doesn't display anything. It's a pitch black screen despite the computer fully functioning in the background. Also, the power button for this machine is green, not yellow, which tells me that some data is being sent to the machine. When I disconnect the VGA cable, the power button usually turns yellow.


Trying to use my monitor as a secondary display for my laptop (which I'm on right now) yields the same problem.


But here's where it gets really weird: If I press the power button to turn the monitor off for a brief moment, and then turn it back on, I will get a display on the screen for about 1.5 seconds ... only for it to suddenly go dark again.


In the brief moments I can get the monitor to work, I can see my Windows desktop image in the background, with all my icons. So that at least assures me that the computer itself is still booting up.


I also use a VGA-to-HDMI adapter. But I'm fairly certain that isn't the problem because, as mentioned before, switching to my laptop still causes the same problem of the monitor only briefly working before going black again. I can connect my VGA cable into my laptop directly, so eliminating the HDMI connector has no effect. Thus, the connector isn't the problem either.


So at this point, we've narrowed the problem down to one of two components: The monitor itself, or the VGA cable?


Is there any way to tell definitively which one is the problem?

My current build:


Motherboard: Gigabyte GA-970A-UD3P
Processor: AMD FX-8350
RAM: 12GB (2x2GB+8GB)
Video Card: Geforce GTX 1050ti

OS: Windows 7 64-bit Ultimate

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#2 Platypus


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Posted 22 February 2018 - 08:27 AM

It's almost certainly going to be a backlight fault in the monitor, showing briefly when first powered on is a typical symptom that there is no reason for the VGA cable to cause.

One way to check is with the system including monitor powered up, so that you would briefly see the desktop if you power cycled the monitor, get a small flashlight, turn off the room lighting and gently rest the flashlight, lit, against the front of the screen. If you faintly see the desktop images in a circle of reflected torchlight, then everything is operating up to the screen inside the monitor, except the backlight is not lit.

Edited by Platypus, 22 February 2018 - 08:30 AM.

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