Monitor WTF
April 8, 2014 9:04 AM   Subscribe

About six months ago we started having issues with our computer monitor. Upon booting our 2-ish-year-old Dell desktop, the monitor would blink on and off a couple of times, then work as normal. As time went on, the blinking went on longer and longer until it was doing it for close to a half-hour.

We switched out the monitor and things went back to normal for a while until that monitor began doing the same thing. Things got so bad that it would blink for a day or more and we wouldn't be able to use the computer. Eventually we just left the computer on all the time once the monitor was usable and that worked great until somehow it got turned off a few days ago and we haven't been able to get the monitor to work since then.

The computer is working fine and booting up normally. We have tried both monitors again and neither work. I have plugged both of them into the wall alone and they blink. I find it hard to believe that the power cords are bad on both of them, but is that the case? What else can I try? What else could it be?
posted by altopower to Technology (10 answers total) 1 user marked this as a favorite
Are these identical monitors? Have you tried plugging them into a different power outlet?

Check the monitor warranty. If one or both was purchased with a computer, it's likely that they have the same warranty as the computer.

If they're identical, it could be that they're both bad with the same issue. If they're not, either there's something wrong with the power coming from that outlet (which will be apparent by plugging them into another outlet), or it may be that bad power from the outlet goofed up both monitors the same way. Either way, consider getting a small UPS, which will deliver consistent power to the monitors and will eliminate the chance of burning out a third monitor, if that's what happened the other times.

It's not likely to be two bad power cords. I don't think I've ever seen a power cord go bad.
posted by cnc at 9:14 AM on April 8, 2014

I think you need to isolate whether it's really the monitor or the computer. For it to happen on two monitors is ... weird. If you could try one of the monitors on another computer, that'd be good.

I'm leaning towards it not actually being the monitor but instead being the computer's video card. A failing video card can cause lots of weird intermittent issues. The common cause is bad solder joints creating loose connections as the card heats up and cools down.

If the video card is a removable one (or if the computer has the ability to take a removable video card, e.g. a 16x PCIe slot), you could replace it inexpensively and see if that fixes everything. If the video card is integrated to the motherboard and there's no way to add an aftermarket one, you may be stuck. (In that case, back up your stuff and prepare to migrate to a new computer...)
posted by Kadin2048 at 9:18 AM on April 8, 2014

Are you also changing the DVI or VGA cable? Cables can fail in very odd ways.
posted by rockindata at 9:25 AM on April 8, 2014

The monitors are not identical. Neither was purchased with the computer, they are both older but not ancient. They have been plugged in to the same power strip with the computer itself so I don't think the power strip is the problem (though I admit not really knowing much about this kind of thing).

I plugged them into a wall outlet last night without having them connected to the computer and they still blinked which leads me to believe it's not the video card, unless a video card can do that kind of damage to a monitor.

When I switched out the monitors I also switched out the cables.

I'm bringing home a monitor from work today to try out and we'll see what that shows.
posted by altopower at 9:42 AM on April 8, 2014

Seconding the video card in your computer.
posted by weapons-grade pandemonium at 10:37 AM on April 8, 2014

Try and replicate this issue by connecting another computer to the monitor, such as a friend's laptop. If the same behavior occurs, the problem lies with either the monitor or the cable. If the same behavior does not occur, the problem lies with the original computer.

If the same behavior occurs on another computer, try replacing the VGA/DVI cable you're using. If that still doesn't solve the problem, buy a new monitor.

Is your monitor plugged into a power strip by any chance?
posted by oceanjesse at 12:47 PM on April 8, 2014

I brought a monitor home from work and plugged it in and it works fine so far (though obviously it has to go back tomorrow). My plan is to take the old monitors to work with me tomorrow and try them with a computer there though my guess is that they won't work. And yes, the monitor is plugged into a power strip, though it behaved similarly when plugged into a wall outlet after it became unusable.

If it's the video card, is it possible that it somehow destroyed both monitors but not the computer? And would it possibly destroy this work monitor before tomorrow morning (eek)?
posted by altopower at 2:35 PM on April 8, 2014

Are these LCD/LED monitors (flatscreens)?

I haven't heard of a bad video card destroying a monitor since the very early days of CRTs. And I don't think it was even possible on the later generations of CRT, they had self-protection circuitry built in.

Either it was just coincidence the two monitors failed at the same time, or there's something weird going on with your electric supply, or there's something else going on that's causing them to fail that hasn't been described. (Are you testing EMPs in the next room? Is someone running an arc welder on the same circuit? Etc.)

I'm curious whether the monitors are really broken or whether they're in some sort of weird mode, perhaps as a result of getting a bad input from the computer. When you say they're "blinking on and off" do you mean the entire screen backlight is blinking on and off? Or just the power indicator light blinking on and off? If it's the latter it could be some sort of error triggered by a bad video signal, especially if the monitor hasn't been reset by connecting it to a good signal since. If it's the actual screen backlight flickering on and off even in the absence of a video signal at all ... that's pretty strange. I've never seen that before.
posted by Kadin2048 at 2:50 PM on April 8, 2014

On the wall outlets, too? Hmm. How's your voltage -- any fluctuation? Do any other devices, like incandescent lamps especially, exhibit this behavior? How sensitive your equipment is can depend on a lot of things.

You can probably get the power company to come out and give you a clean/not bill of health as far as that.
posted by dhartung at 1:10 AM on April 9, 2014

Yes, these are flatscreens. The blinking was originally the backlight going on and off, but now is to the point where it's just the power indicator light, even when it's connected to the computer. I brought one with me to work and I connected it to one of the PCs here and as expected, it doesn't work. The power indicator light just blinks. So, I guess we'll just buy a new monitor and hope for the best. I'd still like to know the cause, though, just so we don't burn out another one, but maybe there's no answer.

We don't seem to have any problems with voltage...the computer and other devices are plugged in in the same general area and don't have issues.
posted by altopower at 7:44 AM on April 9, 2014

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