I have a bizarre problem with my Hyundai W240D monitor, I have it connected to my video card via a DVI to HDMI adaptor and then via a long HDMI cable. I also have a HP ZR24w monitor connected the same way (the only difference is that it also has a HDMI couple and a HDMI to DVI cable). The HP has no problems at all.

Since I cannot describe the problem in words, here is a video I took of it happening ... http://www.youtube.com/watch?v=WhHNigEzrRw

Has anyone seen anything like this before? I suspect it's the cable that is at fault. As I also get horizontal lines flickering across the width of the entire screen depending on what it on the screen at the time they appears at different positions.

The Effect! It starts off by the colours going "hatched", fading in between looking focused and defocused (the hatching), then blocks of distortion appear (usually at the bottom), the it seems to fade to black and back again, but still with the image underneath. Eventually it ends up with a kind of black "blob" taking over the screen and spreading to the edges but not quite blacking out the whole screen.

Additional Information My setup is as follows ...

  • W240D Monitor connected to 1st DVI output of video card via DVI to HDMI adaptor and long HDMI cable
  • HP ZR24w Monitor connected to 2nd DVI output of video card via DVI to HDMI adaptor and long HDMI cable, then to a HDMI coupler and a short HDMI to DVI cable

The reason for this is that I have my PC located in the loft while my monitors (and all USB equipment, via an active USB extension cable) are in my office.

The HP monitor has no problems at all with either cable connected to it, and neither does the Hyundai monitor when only one cable is in use. But when I plug both monitors in I get the effect shown in this video.

So, I've tried the Hyundai monitor plugged into both HDMI cables coming from the loft and only when both are plugged in does it have the problem. But the HP monitor is perfect. So, it could be interference between the two cables, but the HP doesn't have a problem. So, maybe there is a fault/design flaw in the Hyundai's HDMI connection where it's overly sensitive to interference where the HP isn't.

I am still completely stumped by this.

  • This being a Q&A site, while a link to a Dropbox folder might suffer link rot far too soon, I guess you really must try to describe things in words... (I did not watch the video.)
    – Arjan
    Commented Dec 16, 2010 at 12:17
  • @Arjan: I don't know how I would describe this problem, other than psychedelic.
    – paradroid
    Commented Dec 16, 2010 at 12:23
  • If you suspect the cable - have you tried borrowing the cable from the working screen and seeing if the problem occurs then? (FYI: I also haven't watch the video)
    – DMA57361
    Commented Dec 16, 2010 at 12:28
  • i looked at the video...that's weird...essentially the screen brightness cycles from low to high in unpredictable ways and a black blob engulfs the screen at one point...no ideas Commented Dec 16, 2010 at 12:28
  • @paradroid - indeed. I will try to describe it and add to my question Commented Dec 16, 2010 at 12:29

2 Answers 2


On my friend's laptop which also was in an HDMI setup saw nearly same situation.
It goes black, blue, red, and normal in random frequences or events (e.g. on boot, playing games, writing docs, waiting idle).

We discovered that laptop's HDMI output was overheating.

You might want to swap out the HDMI cables or maybe cool down the computer.

  • I don't think it's that. My CPU monitor is reading 41C and system temp is 32C. Interesting that someone else has seen it though. Commented Dec 16, 2010 at 13:01
  • Actually i didn't refer the system or cpu temp. In our laptop, only the hdmi out is heating, not the system or cpu or gpu or anything else. the not so related but in like our sony vaio issue : forum.notebookreview.com/sony/… Commented Dec 16, 2010 at 13:31
  • as I said the computer is in the loft, which is pretty cold at the moment. So, are you saying the HDMI port itself could be overheating? I only quoted my GPU (i made a typo, my GPU temp is 41C) and System temps as they're pretty low. Commented Dec 16, 2010 at 14:11
  • Yes, only the HDMI ports (both on monitor and converter) could be overheating. Commented Dec 16, 2010 at 14:17
  • actually, now you come to mention it the Hyundai monitor does produce quite a bit of heat. I'll try plugging it back in when it's cooled down. Commented Dec 16, 2010 at 14:36

My graphics card has two power connectors to it, for that extra oompf. Could be that its not got enough power to run two cables. Can you check your power connectors to your graphics card.

Alternatively, try swapping the graphics card and see if that helps. That way you'd know for sure if its cables or graphics card.

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