YP1922-4L LCD power board repair

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  • Honziq
    Senior Member
    • May 2014
    • 58
    • Kazaksa

    #1

    YP1922-4L LCD power board repair

    I have LG LCD TV. When I turn on the TV backlight turns on for 1 sec and then goes back off. I think it is bad invertor. But i dont know, which of components is bat. MOSFETs and caps seems OK.
    Help me, please.
    Thanks.

    Attached Files
  • selldoor
    Slow Learner
    • Dec 2010
    • 7870

    #2
    Re: YP1922-4L LCD power board repair

    Ok you need to test the inverter transformers secondary windings.
    No Power to Board
    Meter on Ohms 2000 test S1 to S2 and S3 to S4 and post the results
    I will be going to bed soon - early start tomorrow - someone else might follow up

    Which country are you in and mains voltage
    Attached Files
    Last edited by selldoor; 07-15-2014, 03:55 PM.
    Please upload pictures using attachment function when ask for help on the repair
    http://www.badcaps.net/forum/showthread.php?t=39740

    Comment

    • Honziq
      Senior Member
      • May 2014
      • 58
      • Kazaksa

      #3
      Re: YP1922-4L LCD power board repair

      Originally posted by selldoor
      Ok you need to test the inverter transformers secondary windings.
      No Power to Board
      Meter on Ohms 2000 test S1 to S2 and S3 to S4 and post the results
      I will be going to bed soon - early start tomorrow - someone else might follow up

      Which country are you in and mains voltage
      S1 to S2 - 1080 Ohm
      S2 to S3 - 1092 Ohm

      Comment

      • Honziq
        Senior Member
        • May 2014
        • 58
        • Kazaksa

        #4
        Re: YP1922-4L LCD power board repair

        Originally posted by selldoor
        Ok you need to test the inverter transformers secondary windings.
        No Power to Board
        Meter on Ohms 2000 test S1 to S2 and S3 to S4 and post the results
        I will be going to bed soon - early start tomorrow - someone else might follow up

        Which country are you in and mains voltage
        Hello,
        I am in Czech Republic, mains voltage is 220V.

        Comment

        • selldoor
          Slow Learner
          • Dec 2010
          • 7870

          #5
          Re: YP1922-4L LCD power board repair

          Ok they look alright. Are the leads on the lamps long enough for you swap each pair over.
          Often the bulbas at the top age faster and developa a higher resistance.
          Do you have any spare bulbs /another faulty ,even broken monitor or laptop screen.
          Please upload pictures using attachment function when ask for help on the repair
          http://www.badcaps.net/forum/showthread.php?t=39740

          Comment

          • Honziq
            Senior Member
            • May 2014
            • 58
            • Kazaksa

            #6
            Re: YP1922-4L LCD power board repair

            Thanks,
            i try to swap tubes with one laptop screen tube.
            One of the top tubes is bad. When laptop screen is connected TV running always.
            Thanks a lot.

            Comment

            • selldoor
              Slow Learner
              • Dec 2010
              • 7870

              #7
              Re: YP1922-4L LCD power board repair

              Good - Hopefully you can get a tube for it - if its just for yourself and is watchable with just 3 lamps I have heard of people just sitting a bulb inside the back to make it work but to save having to attack the panel. Bulb fitting can be quite tricky.
              Please upload pictures using attachment function when ask for help on the repair
              http://www.badcaps.net/forum/showthread.php?t=39740

              Comment

              • Lumberjack777
                Badcaps Veteran
                • Dec 2010
                • 464

                #8
                Re: YP1922-4L LCD power board repair

                Originally posted by selldoor
                Good - Hopefully you can get a tube for it - if its just for yourself and is watchable with just 3 lamps I have heard of people just sitting a bulb inside the back to make it work but to save having to attack the panel. Bulb fitting can be quite tricky.
                Nice job diagnosing that problem so quickly selldoor.

                I'm one of those people that simply tapes a bulb about the same size or smaller to the panel. And cover it with black electrical tape or duct tape. Unless its a valuable monitor, its way too much trouble to disassemble and spend $15 or more for a bulb for a $25 monitor. We might start replacing with LED strips someday soon.

                Comment

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