AOC U34G3XM, new monitor, black screen with backlight on, possible shortcircuit during dissassembly

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  • turmix
    New Member
    • Jan 2024
    • 8
    • Switzerland

    #1

    AOC U34G3XM, new monitor, black screen with backlight on, possible shortcircuit during dissassembly

    Hello, I'm working on a new deskmod pc project and have a problem with my monitor, an AOC U34G3XM, well, I may have bricked it.

    The monitor was dismanteled and the separate parts parts integrated in the desk. the screen panel alone is on the upper part, and main board/video board + power board on the back of the desk (not enough place on the cover to fit it)
    At first everything was working smoothly, then I decided to change the connexion between the video board and the screen for a longer one. Still working fine

    During another reassembly, I made a mistake, and teared some tracks on the cable between the video board and the screen, some glitches on the screen then... black screen.

    Aaaargh..

    Symptoms: black screen, no OSD, no logo at startup, but backlight is still functionning, and the power led is functionning correctly.

    With a Displayport cable on, at first the power light turn white (on), the backlight is on but there is no image. Then the power light go back to sleep (orange) in 5 sec and the wake up signal from displayport is not working.
    with a HDMI cable on, the wake up signal is working, the screen and backlight stays on, but I still have no image. It seems that I have fried partially the video card

    The power board seems fine, the output voltages for backlight and video board are ok (tested live with a multimeter )
    I don't know where to start troubleshooting for the video card, I checked with a magnifiying glass the components, and nothing is obviously burned/cracked.

    If somebody could give me some advices, it would be great, and I will try everything to repair it.

    I have a multimeter, some micro soldering skills and material, and I hate the idea of new material bricked just for some parts i'm too dumb to find by myself, that's why I ask for your help.

    And I'm sorry if some informations are missing, I will be glad to add anything that can help

    Click image for larger version

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  • turmix
    New Member
    • Jan 2024
    • 8
    • Switzerland

    #2
    Hello, I found that there is no conductivity on all these capacitors (I guess that's a bunch of capacitors because of the "C" before the part numbers? )

    I can change them if somebody could help me find the specifications ? Anyway I keep searching, all the others fuses, capacitors, resistances on this board have a value ..Click image for larger version  Name:	IMG_3109.jpg Views:	0 Size:	564.7 KB ID:	3207166 Click image for larger version  Name:	IMG_3108.jpg Views:	0 Size:	1.37 MB ID:	3207161
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    • turmix
      New Member
      • Jan 2024
      • 8
      • Switzerland

      #3
      here is one of the "no conductivity, no resistance" caps on a size gauge

      Click image for larger version

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      Comment

      • vf fa
        In over my head
        • Jan 2024
        • 19
        • Germany

        #4
        You mean you managed to tear the cable that connects to Mainboard to the T-Con? (LVDS).

        That shouldn't kill the monitor. At least in theory. Unless you managed to short something while doing so.

        You said you replaced the flex cable for a longer one. Have you tried the shorter cable again?

        What do the capacitors measure when removed from the board (capacitance mode). It's unlikely that you managed to damage them all, so this might just be how they were designed. Look for fuses, and take measurements from the probing points on the T-Con board while plugged in and powered up.

        I'm an amateur myself, so take everything I'm saying with a grain of salt.

        Have a confusing problem with my monitor myself right now, so welcome to the party.

        Comment

        • alektro
          New Member
          • Feb 2024
          • 1
          • Indonesia

          #5
          Can you show me where the capacitor is located where there is no resistance?

          Comment

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