Getting strange boot-up artifacts

[TheBigFarmer]

Hey guys, I've been having a strange and worrying problem with my PC for the last few weeks

This is what it happens when I turn my PC on: https://www.youtube.com/watch?v=A0vSjdOZDo0

When it first started happening, it was very brief (lasted just a few seconds) as soon as Windows finished loading. This first led me to believe it was a software (possible GPU driver) issue. So I reinstalled my drivers, but the problem didn't go away. Then, each day, it started to last longer and become worse. It's now started happening over the POST-screen, which means it's probably a hardware issue.

The problem now lasts for a good few minutes, starting immediately when I turn the PC on and won't go away for a few minutes, though Windows still loads normally behind the artifacts and I can even log in (though I can't see anything), but the artifacting still won't go away for about a minute after I'm at the desktop. Basically, it seems to be a graphical only problem that lasts for a set amount of time (which seems to increase every day as well). But here is the weirdest part about it:

It only happens if the PC has been off for a while. For example, I turn the PC off, go to bed, wake up the next day, turn the PC on, it happens. If I just reboot or power down then power on straight after, nothing happens. It seems that the longer the PC is off for, the longer the effect occurs.

My next thought was that it might be my GPU dying. However, I don't get any other problems other than this boot-up issue; no artifacting at the desktop, no problems in-game, etc. Forunately, I had a spare GPU lying around and put that in. I turned the PC on straight after putting the GPU in, and I got a slightly different problem: I got a very small amount of artifacting as Windows started to load (the loading circle below the logo was scattered across the bottom of the screen, and a few black lines struck through the logo itself), and Windows actually didn't load; the PC rebooted itself, and then it worked fine, no artifacting. However, because I can only reproduce the effect (in the video) if the PC has been off for several hours, I can only do 1 test a day. After testing my other GPU, I turned it all of, went to bed, came on the next day, the effect happened again. So it would seem the GPU isn't the problem. I put my original GPU back in (MSI 280X) and again, Windows didn't load and I had to reboot 2 times for it to work.

My next suspicion was a dodgy power supply. I read about cold boot errors, and it would kind of explain why the affect only happens if the PC has been off for a while. I also have a spare PSU, so I plugged that in, tested it the next day, and the exact same issue occurred. So it can't be the PSU.

I'm now running out of ideas (can still test the monitor, but it wouldn't really explain why the effect only happens after the PC has been off for a while, and also wouldn't explain the failures to boot the two times I changed the GPU).


Does anyone have any idea what could be causing the problem? It doesn't seem like a serious problem right now as I only get an issue during boot-up (including the post-screen), but the effect does last slightly longer every day, and who knows what might happen next.

Thanks for reading, sorry for the wall of text!

tl;dr: my PC screen goes nuts when I turn the PC on (only after several hours of being off, rebooting is fine). It looks like the GPU and PSU aren't the problem.

 

[TheBigFarmer]

Well, looks like the monitor was the problem all along. I tried swapping monitors with another PC and the effects carried over to the 2nd PC, while my main one was fine. I don't know why it wasn't the first thing I tried out.

 

[TheBigFarmer]

After some more experimentation, it looks like any darkness on the monitor causes it to corrupt. For example, if I open up a large image with a lot of dark colours on it, or even turning the brightness down through the OSD causes the corruption to appear. The darker the image on the screen, the worse the effect gets. Changing back to a brighter image/turning the brightness back up fixes the problem immediately. Any ideas what could possibly cause this? Perhaps bad capacitors?

 

[TheBigFarmer]

Well, over half a year later, I managed to fix the problem. Although I posted this like 8 months ago, I thought I'd come back and post my solution anyway, in the small chance that it might help someone else out there.

RECAP: About half way through last year, I started noticing that my BenQ XL2411T 144hz monitor (which I had owned for 3 years at this point) was having some strange corruption artefacts that was progressively getting worse as the weeks went by (video: https://www.youtube.com/watch?v=Kr4ZM32yA3Q). I didn't know what it was at first; perhaps it was the graphics card, some driver problems, or the monitor itself. After trying out different monitors and GPUs, I concluded that the monitor was the problem. Eventually, the issue got so bad that I had to buy a new monitor, so I went with its successor: the BenQ XL2411Z (144hz <3).

However, I don't like throwing broken stuff away, so I decided to stuff it under my bed and leave it, so that one day I maybe I could try opening it up and seeing if I could fix something. After all, the glass hasn't cracked or anything, so maybe I could so something, but the problem did look very bad regardless.

And today that day has come (well, more like the past few days). In my most recent reply I suspected (more like an educated guess, I know barely anything about electronics) that perhaps a burst capacitor was the problem, but really I had no idea. So I opened the monitor up (haven't opened a monitor before so I was quite anxious about all the plastic clips around the bezel, hoping I didn't break any of them) and wouldn't you know, my suspicions were true; a couple of 680uF 16v capacitors had gone bad, with one of them bulging and the other had outright burst at the top.

http://imgur.com/rCOA7Mv
Here's a photo of the monitor's guts. Not a very useful photo though, I didn't take a picture of the burst capacitors for some reason.

http://imgur.com/TRoqADy
And here's my ridiculous setup. To save myself from having to constantly disassemble and reassemble the monitor, I placed the monitor downwards and placed the circuit boards on top of a magazine resting on the back of the monitor itself. I had to do this because the cables were far too short to have it any other way. However, if I had the monitor facing directly down on the floor then, well, I wouldn't be able to see it. So I suspended the monitor with some boxes and used a mirror to get a rough idea of what was going on with the screen.

So I went on Amazon and bought a couple of replacement capacitors. I did very little research about capacitors and "concluded" that I'd be okay getting some 1000uF caps, as I couldn't find an 680uF ones. 2 days later they arrived, I soldered them on, and the majority of the problem was gone. However, now there was a new problem; exactly half of the monitor was all fuzzy and corrupt looking. It wasn't nearly as bad as the initial problem, though it was still unacceptable. Perhaps getting 1000uF capacitors was a bad idea and I should've just been sensible and found some 680uF ones instead? I hopped on to eBay (why didn't I just do this in the first place) and got some 680uF capacitors for even cheaper than the ones I got off amazon. 2 days later, I take off the 1000uF caps and stick the 680uF ones on. But the problem is the same; the really bad artefacts were gone, but still half the screen was all fuzzy and corrupt.

I was starting to feel defeated at this point, that perhaps there is another issue with this monitor that I won't be able to fix. Did I break something else when opening the monitor up? Who knows. Anyway, I did another google search to see if anyone else had this strange issue where exactly half the screen was going fuzzy, and well, all this sorrow and it turned out its just something to do with the refresh rate. I was testing the monitor using a dual-link DVI cable in to a DVI to display port adaptor hooked up to a laptop (my laptop doesn't have DVI on it, only DP).

http://imgur.com/K6wx2vp
So, I brought the mess over to my desktop, plugged the DVI straight in, and all was well!

If only I had done this 8 months ago, I could've spent £1.50 on a working monitor instead of a full £220 Oh well, I guess I can have a dual 144hz monitor setup now!

Thanks for reading, and hopefully this post can help someone out there. If your monitor is having some really bad artefacts, but the LCD itself isn't actually cracked, you might just be able to correct the problem with no more than a few pounds (and some simple soldering).

 

[Cracoidic]

Thank you... i have the same problem and also... same monitor. I'll try your solution.

 

[Cracoidic]

Replaced bad capacitors with similar ones (680uF, 105C) but I found only with higher voltage limit, 25V. Bigger voltage limit is always fine for capacitors anyway.
Problem went away.
Thank you for your instructions.

 

[Crispy Whiskery]

Thank you for posting your solution, same monitor (think its about 4 or 5 years old now) EXACT same problem. Will def try replacing the capacitors.

 

[oscar.olsson]

Took about 5 months before the artifacts on my monitor got so bad i couldnt use it at all. Live in EU and found new capacitors with 680 uF 35 VDC here:

https://www.elfadistrelec.no/en/aluminium-electrolytic-capacitor-680-uf-35-vdc-panasonic-automotive-industrial-systems-eeufm1v681/p/11070068?q=EEUFM1V681&page=1&origPos=1&origPageSize=25&simi=99.65&no-cache=true

but they were physically bigger in size (almost twice as big). Switched them out and they worked fine. Thanks TheBigFarmer