Faint horizontal lines when screen is black - Please help!!

Discussion in 'Archived Threads 2001-2004' started by Scott Kroll, Mar 6, 2002.

  1. Scott Kroll

    Scott Kroll Agent

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    I tried to search for this, but could not find anything.

    I am actually doing some research for a neighbor of mine who has a 27" Sony Flat screen. Not sure of the exact model, but it is probably 4 years old and still has a great picture. Here is the issue... When watching TV and the picture is bright you don't notice too much, but in darker scenes or especially when a program switches to a commercial and the screen is black there are 10 to 15 horizonal white lines that are spaced about 1 inch apart that run across the screen.

    I have tried different cables (Composite, RCA and S-video) and it has not fixed the problem. Has anyone seen this before and is there anyway to fix it?

    Thanks for the help
     
  2. Jack Briggs

    Jack Briggs Executive Producer

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    I doubt that his set is four years old; Sony has only marketed 27-inch WEGAs in the U.S. for about two years.

    Where exactly are these lines located? At the extreme top or the extreme bottom of the screen? If so, it sounds like he has zero overscan. Can't say anything more definitive without a more detailed description of the problem.

    Gregg Loewen, do you want to take a crack at this one?
     
  3. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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    Gregg Loewen
    well since you requested...
    How is the brightness and contrast set? Ive seen a lot of artifacts on sets where the B and C have been cranked. If turning these settings down fixes the problem then your golden.
    If not...
    then it is an interference issue inside of the set (since you have mentioned that you have already trouble shooted with different cabling and source materials). Time to call the service tech (and hold your breath) [​IMG]
    Regards
    Gregg
     
  4. Scott Kroll

    Scott Kroll Agent

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    Thanks for your help.

    The horizontal lines the entire length of the tube. They start at the top of the screen and are spaced about 1 inch apart and run all the way to the bottom.
     
  5. Allan Jayne

    Allan Jayne Cinematographer

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    Scan lines 483-525 may be appearing on the picture tube as the electron beam returns to the top. Lowering the brightness may help. Also look in the service menu for controls described as electronic matting (or vertical retrace). Otherwise only a serviceman would know if or how it can be fixed.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     

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