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Monitor Flickering


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Monitor Flickering

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I just bought a new Dell XPS 1640 and hooked it up to my Dell 2407WFP monitor.  The monitor worked fine with my other Dell laptop and I have used a VGA cable.  I just went through several frustrating hours with technical support to find the problem - the flickering goes away when I unplug the AC power adapter.  Dell tech support told me to "go buy a new cable".   ...that the hardware was working fine and "as designed" (yeah, I don't think so).   Finally they got me to a supervisor and he tried to convince me that everything is fine.  ...but maybe I should go out and buy a HDMi to DVI cable.  I have a Dell laptop, a Dell monitor and cables supplied by Dell. If something isn't working properly, shouldn't Dell offer to send replacement cables? 

After searching the internet, I find that this is a "known issue" and I am not alone.  I'm sure a few of you have had this problem as well.  Since i hit a dead end with the tech support folks on chat - should I call or email somebody else?  Any suggestions?


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  • An update to this post.  After some extensive searching, I find that I'm not alone in this issue.  Although Dell won't provide an answer, the problem is "ground loop interference".  By snipping off the ground plug on the monitor AC plug (the third "leg" of the plug that is the ground), that solved my issue.  ...gee, maybe that should have been in the manual...  ...sure, one should never do this, but since I was given no solution by Dell, that was all that I had left and it worked.  ...but why hasn't this issue been resolved by Dell?  Why did I have to discover this on my own and resort to such a drastic "hack solution" rather than be given a decent resolution by Dell?  ...not sure, but for certain, our run of 15+ Dell PC's in my office is now over...

  • Thank you very much for your post. I recently bought a Dell Precision M4400, and then a HP 23-in monitor. After connecting the external monitor to the laptop, the monitor kept flickering  I then returned the HP monitor, and bought a Dell 23-inch. However, the flickering still happens. I tried it with a ThinkPad, and it worked no problem. Thinking that now I probably have to deal with the Dell Support, I saw the message you posted. I tried it and it worked perfectly. Although it took only a few seconds to rip off the 3rd leg, who on the Earth would think about it. Anyway, thank you again for the solution. The irony is that in my case, Dell's problem actually generated a sale opportunity for them (though I got a $50 coupon for the monitor, which wasn't bad :-)

  • Confirmed that removing the ground on the monitor's AC plug solves the problem.  I have a new Dell Precision M4400 laptop with a new Dell E2210Hc external monitor.  The external monitor flickers in vertically moving waves of luminosity variation, noticeable especially on dark to medium backgrounds.  When I run the laptop on battery power, the monitor stops flickering.  But if I want to run the laptop on AC power, I need to remove the ground from the monitor cable.  I didn't cut off the pin, I used a 3-prong to 2-prong adapter. 

    This wasn't a generic problem of line-based electromagnetic interference, because I put the laptop and monitor on a high-end power filter (using separated power banks for laptop and monitor), and that made no difference.  Also it wasn't due to over-the-air interference from the laptop's huge adapter, because moving the adapter far away from the monitor made no difference.

  • pefect!!! it works for my laptop DELL U2211H external monitor! Thanks

  • I had exactly the same issue with the my U2311H DELL monitor and an ACER TravelMate 6292 laptop and thanks to your post everything seems to be now fine!! 
    I had tried to narrow down the problem and I had made the wrong assumption that the problem was with my laptop's video card, since by connecting my monitor via VGA with another laptop the problem seemed to be going away...but this wasn't in the end the case, the problems seems to come from the DELL's grounding in a combination with some specific laptops....very strange.... Anyway, my problem is now sorted and I am very happy about it! My eyes had started getting so tired from the flickering, which was mostly appearing while moving the mouse or keyboard.... Many thanks! 

  • I just tried this (cutting the ground pin)......and it did not work for me....................any tother suggestions someone?




  • Hi nonamedad,

    Video flickering issues could also be caused by outdated or corrupted drivers; incorrect settings like the refresh rate and a faulty or loose vide cable.

    Please let me know the models of the system and the monitor that you are using and the operating system installed on the system. Also let me know if the flickering appears all the time or during some specific application. I will then provide you with the specific tests that you can try on your system.

    In the meantime, please check the video connections and ensure that they are not loose. You can try changing the video cable. Also try loading the defaults on the monitor by using the On Screen Display (OSD) menu on the monitor. You may also run a self-test on the monitor. For running the test, please disconnect the video cable from the back of the monitor and power on the monitor. After some time, a box with different colors starts floating on the screen. See if the monitor flickers during this time and let me know.

    Another thing that you can try is changing the refresh rate of the display. The steps are listed below:

    For Windows XP:

    1. Click Start, click Control Panel, click Appearance and Themes, and then click Display.
    2. Click the Settings tab, and then click Advanced.
    3. Click the Monitor tab, and then click one of the screen refresh rate from the options.

    For Windows Vista/7:

    1. Right click on the desktop and click on Screen Resolution.
    2. Select the display you want to change the screen refresh rate for.

    NOTE: You will only be able to select a different display if you have more than one monitor connected.

    3. Click on the ‘Advanced settings’ link.
    4. Click on the Monitor tab.
    5. Select an available Screen refresh rate from the drop down menu.

    WARNING: It is recommended to leave the Hide modes that this monitor cannot display box checked to prevent possible damage to your monitor.

    6. Click on OK.

    You may try different refresh rates and set it to the value that works best for you. You may also try installing the latest video drivers for your system.

    Please revert with the details and findings. Let me know if you need the detailed steps for any of the suggestions above. I will be glad to assist you further.

    Thanks and regards,

  • I had the same problem with vostro laptop 3460 and U2412M  external monitor. If I unplug the power source and run in battery mode, the wave disappeared. Now the problem is that I am in Japan and we use only 2 pin power source. I dont know how to remove the ground loop, if it is the correct reason, in this case. Any help?

  • I noticed that the problem is solved after connecting the monitor using the DVI output, rather than the VGA. Give it a try.

    In my case I had removed the ground pin and had connected the monitor using a VGA cable connector and it was good, although I noticed later that connecting the monitor using the DVI and without having to cut or alter the way the ground pin is connected, the monitor works and the flickering is not happenning any more.

  • Thank you Kongon,

    My laptop does not have DVI output, unfortunately.

    I did try with different VGA cable but it does not work. Still very stuck.

  • Unplugging the power adapter "works" because it puts the laptop into a lower power mode. I only have the flickering problem when my laptop is in high performance mode.

    I have a Precision M4800 with dual vidfeo cards (Intel and nVidia)

  • Thanks for your post!

    I was experiencing external monitor flickering (NEC 2690WUXi2) whenever I ran both the laptop monitor and the external monitor in "extend" mode. It wouldn't happen if I used solely the external monitor. It also wouldn't happen if I used it in "extend" mode, but the laptop wasn't plugged in. I had thought it was something previously to do with the ground pin power connection (as per many other people's experiences) - but I tried removing that to no avail. Then your suggestion came up.

    I have a Studio XPS 1645 with the Radeon 4670M, running Windows 10. I don't use it for games (anymore), so this solution is entirely acceptable to me. I've outlined what I've done below, and it works for me.

    Go to power options -> change plan settings -> advanced power settings.

    Find ATI Graphics Power Settings -> ATI Powerplay settings

    Change the setting for "Plugged in" to be the same as "on battery" (i.e. change it to "maximise battery life")

    This meant the graphics card is now behaving as if it's in "battery mode" all the time. This lower power state seems to mean I don't get the screen flicker on my external monitor in dual monitor use anymore.