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Monitor switches off on its own

Discussion in 'Electronic Repair' started by qwerty, Jul 14, 2007.

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  1. qwerty

    qwerty Guest

    I have a monitor that used to work fine, but now when the
    computer starts up, the monitor switches off immediately,
    without even showing the bios screens. If I unplug it from the
    computer it shows the "signal not found" screen fine. Once I
    plug it in again, it switches off immediately.

    The monitor is a LG Studioworks 700S. I tried it on other
    computers and it showed the same behaviour. It's out of
    warranty, is there any hope of getting it fixed?
     
  2. JAD

    JAD Guest

    I have a monitor that used to work fine, but now when the
    computer starts up, the monitor switches off immediately,
    without even showing the bios screens. If I unplug it from the
    computer it shows the "signal not found" screen fine. Once I
    plug it in again, it switches off immediately.

    The monitor is a LG Studioworks 700S. I tried it on other
    computers and it showed the same behaviour. It's out of
    warranty, is there any hope of getting it fixed?
     
  3. Guest


    WhenI think of black screens, there are several things that can be the
    cuprit. I'll list them here for informational purposes but I'm
    assuming this is a CRT (Big Tube) type display. since you indicate it
    has a power saving feature. Unless you are knowledgeable about the
    extremely high voltage components (20,000 + Volts) inside, DO NOT
    ATTEMPT TO FIX IT ON YOUR OWN AS THE DANGEROUS COMPONENTS INSIDE can
    hurt you.

    List of Culprits
    1. VESA power saving feature, See: http://en.wikipedia.org/wiki/VESA_Display_Power_Management_Signaling.
    These components are designed to turn your screen black (turn off the
    High Voltage) when they cannot detect missing horizontal and vertical
    synchronization signals coming from your video card. But since, the
    monitor knows you pulled the cord and displays it's internal video
    message "signal not found". I would say this is NOT THE CULPRIT.
    2. High Voltage failure will cause a black screen. Since you are able
    to get a "signal not found" message tells me this is NOT THE CULPRIT"
    3. Too much high voltage (transformer circuit creating the high
    voltage goes into a runaway state, an X-ray safe shut off feature
    intended to shut off the monitor as it nears 30,000 volts). Again,
    since you are able to get a "signal not found" message tells me this
    is NOT THE CULPRIT"
    4. Video from the display card is dropped somewhere in the early
    stages as it arrives in the monitor. There are 3-video connectors
    that provide the full range of colors, so I don't think it's a
    connector issue, but possible video circuit malfunctioning in the
    early stages of circuitry, but since the internally injected video
    signal "signal not found" is displayed it has to be in the very early
    stages of video circuitry. If you get a black screen, yet are still
    able to get some background lighting when you turn on contrast/
    brightness controls to maximum, I usually start tracking down the
    video path with an oscilloscope. (POSSIBLE CULPRIT).

    Good luck, but my recommendation with the low price of monitors today,
    you'd be good to trash this device, and purchase a low powered flat
    screen monitor. The power you save in the long run will pay for the
    cost of the new monitor.

    Take care..

    Albert
     
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