Why diagonal lines on monitor screen ??

Discussion in 'Computer Information' started by arajunk@hiwaay.net, Jul 22, 2005.

  1. Guest

    See an illustration of the problem here.

    http://home.hiwaay.net/~ara36/xx0721scrnLines.gif

    These are very thin lines visible only on dark background without
    bright patterns. I don't believe they are associated with lines
    typical of Trinitron CRTs. I can see the wires associated with
    Trinitron CRT only on bright backgroud and there are only three or four
    fully horizonal . Also, I only noticed recently.
     
    , Jul 22, 2005
    #1
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  2. Kenny Guest

    On a TV these are known as flyback lines, when the spot finishes a trace at
    the screen bottom it "flies back" to the top and are normally blanked out.
    Try adjusting contrast and brightness, either or both may be too high. Can
    also be a sign of this blanking not working or of CRT wear.

    --
    Kenny Cargill


    <> wrote in message
    news:...
    > See an illustration of the problem here.
    >
    > http://home.hiwaay.net/~ara36/xx0721scrnLines.gif
    >
    > These are very thin lines visible only on dark background without
    > bright patterns. I don't believe they are associated with lines
    > typical of Trinitron CRTs. I can see the wires associated with
    > Trinitron CRT only on bright backgroud and there are only three or four
    > fully horizonal . Also, I only noticed recently.
    >
     
    Kenny, Jul 22, 2005
    #2
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  3. JANA Guest

    These are horizontal retrace lines. This can most likely be from a component
    failing in the blanking circuits. This also starts to happen when the
    picture tube is starting to go weak.

    Sometimes the retrace lines can be masked by slightly lowering the G2 or
    screen bias voltage to the CRT.

    If you were to remove the cover from the monitor, the screen bias control is
    normally located on the HV multiplier section of the flyback. It would be
    marked as G2 or Screen. In some monitors this bias control may be mounted on
    the CRT circuit board, but this is not as commonly done.

    To adjust this control, have the monitor running to display the condition.
    Adjust the screen bias control, until the lines disappear.

    Take care for safety issues when going in to a monitor.

    There is a proper factory setup procedure for this. The service manual, and
    proper tools would be required. Considering that the CRT and related
    blanking circuits have been well used, and are most likely a bit warn,
    offsetting the adjustment should fix it temporarily. Eventually, the problem
    will get worse with time, and then the proper service would be required.
    Normally, older monitors are not worth putting money in to.

    --

    JANA
    _____


    <> wrote in message
    news:...
    See an illustration of the problem here.

    http://home.hiwaay.net/~ara36/xx0721scrnLines.gif

    These are very thin lines visible only on dark background without
    bright patterns. I don't believe they are associated with lines
    typical of Trinitron CRTs. I can see the wires associated with
    Trinitron CRT only on bright backgroud and there are only three or four
    fully horizonal . Also, I only noticed recently.
     
    JANA, Jul 23, 2005
    #3
  4. Kenny Guest

    Very bad advice. Unless you're trained and experienced with repairing TV's
    etc. NEVER take the cover off a monitor.

    --
    Kenny Cargill


    "JANA" <> wrote in message
    news:...
    > These are horizontal retrace lines. This can most likely be from a
    > component
    > failing in the blanking circuits. This also starts to happen when the
    > picture tube is starting to go weak.
    >
    > Sometimes the retrace lines can be masked by slightly lowering the G2 or
    > screen bias voltage to the CRT.
    >
    > If you were to remove the cover from the monitor, the screen bias control
    > is
    > normally located on the HV multiplier section of the flyback. It would be
    > marked as G2 or Screen. In some monitors this bias control may be mounted
    > on
    > the CRT circuit board, but this is not as commonly done.
    >
    > To adjust this control, have the monitor running to display the condition.
    > Adjust the screen bias control, until the lines disappear.
    >
    > Take care for safety issues when going in to a monitor.
    >
    > There is a proper factory setup procedure for this. The service manual,
    > and
    > proper tools would be required. Considering that the CRT and related
    > blanking circuits have been well used, and are most likely a bit warn,
    > offsetting the adjustment should fix it temporarily. Eventually, the
    > problem
    > will get worse with time, and then the proper service would be required.
    > Normally, older monitors are not worth putting money in to.
    >
    > --
    >
    > JANA
    > _____
    >
    >
    > <> wrote in message
    > news:...
    > See an illustration of the problem here.
    >
    > http://home.hiwaay.net/~ara36/xx0721scrnLines.gif
    >
    > These are very thin lines visible only on dark background without
    > bright patterns. I don't believe they are associated with lines
    > typical of Trinitron CRTs. I can see the wires associated with
    > Trinitron CRT only on bright backgroud and there are only three or four
    > fully horizonal . Also, I only noticed recently.
    >
    >
     
    Kenny, Jul 23, 2005
    #4
  5. Guest

    They do disappear when I back the brightness all the way down. Think
    I'll just live with the situation for now rather than fiddle with
    12000 volts. :)

    Thanks to all !!!!
     
    , Jul 24, 2005
    #5
  6. Guest

    They do disappear when I back the brightness all the way down. Think
    I'll just live with the situation for now rather than fiddle with
    12000 volts. :)

    Thanks to all !!!!
     
    , Jul 24, 2005
    #6
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