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VisionQuest 24" monitor: works sometimes

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    VisionQuest 24" monitor: works sometimes

    VisionQuest 24" monitor
    Product name: VQL-24WD
    Model: 1,050
    Manufactured: July 2009

    Problem: Works sometimes. When on, stays on until screen or laptop are turned off. Restarting can take weeks.

    Background: Bought new around 2010. Used for 2-3 years, then had problems, stopped using. Sat around until a few months ago. Plugged it in to laptop and it worked! Used it for around a month at a time, a couple of times. However, when screen or laptop went to sleep or laptop turned off, then turned on again, monitor was dead. (I kept laptop on and no screen sleep to keep it going for weeks.) Once off, getting monitor to turn on again could take weeks of trying.

    Details: The monitor power button doesn't seem to work. I plug it in at the AC, the power light blinks a few times, then either:

    ...image appears and everything's fine, all control buttons except power work.

    OR

    ...power light goes off. Sometimes, the splash screen with the manufacturer name appears before this happens. Sometimes, the power light stays on unblinking for a couple of seconds before going out. If I replug immediately, either after unplugging when blinking stops or during blinking, sometimes the same blinking happens. After max two plugins, nothing happens when replugged, no power light at all.

    IMPORTANT: This behavior seems connected to how long the monitor has been left unplugged. After about a day, replugging will get blinking. Before that, usually not. The second time I got it restarted, I left it for about a month; when I plugged it in, it worked. But a month is no guarantee, and that's the longest I've left it, other than the years it was unused.

    Even if I can't fix this, I'm trying to find out what might be wrong before adding it to the planetary landfill. It seems such a waste since there's apparently a perfectly fine monitor just past the blinking.

    Thanks.

    #2
    Re: VisionQuest 24" monitor: works sometimes

    Does this monitor use a separate power supply adaptor? If yes, try another adaptor, if no
    Sounds like a bad capacitor in the power supply, You will need to open it and post some pictures, Usually a bad startup cap on the controller ic vcc line.
    Last edited by R_J; 05-12-2022, 04:13 PM.

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      #3
      Re: VisionQuest 24" monitor: works sometimes

      No separate power supply. I'll open it up and take some pics!

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        #4
        Re: VisionQuest 24" monitor: works sometimes

        When you open it up look at the area around the switching power supply transformer there should be a switching power supply regulator of some type there should be some very low value capacitor under 50uf replace them if there are more than one and see if it is still doing the same thing if this resolves the issue recap the board except the main filtering capacitor unless it is leaking or the top or bottom of the capacitor are swollen then replace it as well
        Last edited by sam_sam_sam; 05-13-2022, 11:34 AM.
        9 PC LCD Monitor
        6 LCD Flat Screen TV
        30 Desk Top Switching Power Supply
        10 Battery Charger Switching Power Supply for Power Tool
        6 18v Lithium Battery Power Boards for Tool Battery Packs
        1 XBox 360 Switching Power Supply and M Board
        25 Servo Drives 220/460 3 Phase
        6 De-soldering Station Switching Power Supply 1 Power Supply
        1 Dell Mother Board
        15 Computer Power Supply
        1 HP Printer Supply & Control Board * lighting finished it *


        These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

        1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
        2 Hem Saw Computer Stack Board

        All of these had CAPs POOF
        All of the mosfet that are taken out by bad caps

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          #5
          Re: VisionQuest 24" monitor: works sometimes

          Opened the case. Best shots I could get without two sides separated.





          What do I need to take apart? I have to figure out how to unplug the various connectors to separate the screen from the back without breaking anything during the unplugging. Working things out as I go...
          Attached Files
          Last edited by Curious808; 05-14-2022, 11:45 AM.

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            #6
            Re: VisionQuest 24" monitor: works sometimes

            Examined the capacitors. No bulging or leaking, all look clean The white stuff on some of them I IDed as glue.

            What's next step? Do I remove all the capacitors and test them?





            Attached Files

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              #7
              Re: VisionQuest 24" monitor: works sometimes

              I would start by replacing the small electrolytic next to the mosfet in the center of the power supply board, this cap can dry out over time and result in the power supply not starting
              Attached Files

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