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Horizontal scan lines seen on TV

Discussion in 'General Electronics' started by Samir, Dec 28, 2003.

  1. Samir

    Samir Guest

    It seems to me that I see horizontal scan lines on TV. They are
    white lines and visible clearly whenever the picture is dark or there
    is no signal. The image quality behind the lines are still good.
    My TV is Samsung CS6818Z. Has anyone experienced this? Has anyone
    know how can I fix this?

    Thanks in advance,

    Samir
     
  2. sofie

    sofie Guest

    Samir:
    Have you tried backing off on the brightness and contrast a little. What
    you described can also be caused by an improperly adjusted screen control on
    the flyback high voltage transformer...... read "high voltage".... dangerous
    to novices.... electrical shock hazard, etc.
    You may want to have an experienced tech do a proper and safe adjustment for
    you.
     
  3. b

    b Guest

    Seen this many times, need to adjust Screen pot on LOPT/ flyback
    transformer. Read the FAQ for this newsgroup.If you still arent sure ,
    take it to a tech. This is not an expensive problem.
    Ben
     
  4. Rich Grise

    Rich Grise Guest

    They're probably the vertical retrace, which is supposed to happen
    during the "vertical blanking interval." So it's either an intensity
    or contrast adjustment, or something about the vertical sync phase.
    TV's used to have a "vertical hold" control, which was nothing but
    the vertical osc. freq. control; adjusting it would change what
    part of the cycle lined up with the sync. pulse (hence "phase.")

    If you can find a pot with a label tha sounds like one of these, you
    can probably diddle with them without destroying the set - one
    advantage is that you can see the result of your diddling real-time.
    You might need a mirror. And a cheater cord. :)

    Have Fun!
    Rich
     
  5. Samir

    Samir Guest

    Thanks all for the help. This will be my next weekend project :)
     
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