Red output missing in video signal

Posted on 2006-04-25
Last Modified: 2010-04-25
Ever had the R part of the RGB disappear?

I was building my new computer, and took several components out of the old one.  I took out the video card, a Geforce 6800GT, and set it on top of my (plastic) case.  After I got everything I needed, I put the video card back in, and gave the case, containing the mobo, the CPU, and the graphics card, all properly installed, to my boss for him to play with at home.  However, in two days of trouble shooting, he can't get any red to come from the video card.  The blue and green channels are fine, giving everything a teal tint.

He's reseated the card, changed monitors, tried an analog to digital adapter, and verified the cable worked by using it on another monitor.  He's running a 19" Acer LCD monitor.

Question by:mvarner2000
    LVL 69

    Expert Comment

    Normally, I would check for bent pins or a bad cable, but if you used the cable on another monitor and swapped monitors, it's time to look at the video card.  Check for a bad socket connection, or swap the card out for another one.  If the POST screen has white lettering, then I suspect a Windows setting, because a hardware problem would show teal letters there.
    LVL 3

    Author Comment

    The POST screen is tinted teal as well.  He's tried an old 16MB video card which seems to be OK.  

    He's going to bring the video card in tomorrow and try it in another machine here at work.  That will erase any doubt as to whether it's the card or not.  Just can't figure out how it would have happened, as little and carefully as it was handled.
    LVL 70

    Accepted Solution

    Cards do fail -- although so do pins.  Carefully check the connector at the rear of the video card; and try another cable -- even though the one he's using tests okay, it may not quite be making contact with the red signal; either because the pin isn't quite long enough (you could look at the cable to see if this looks likely) or because the socket has receded a bit.   If your boss doesn't have another cable, tell him to try the same cable with the ends reversed.

    LVL 3

    Author Comment

    Well, he got it working last night.  He saw an old CGA cable in his closet and just tried it on a whim.  Fixed the problem.  garycase gets the points because he mentioned the video cable!

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