Aoc Lm727

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  • anno
    Senior Member
    • Sep 2007
    • 140
    • netherlands
    #1

    Aoc Lm727

    I have a AOC 17 inch lcd monitor, model LM727 with a backlight problem.
    the ccfl lamps goes off after an hour. The Green light stays on and if i look on the screen there is still an image visible , but the lights are off.

    I checked all caps with ESR meter, and they were all good. And i resoldered some things in inverter area. But still the same problem

    What can be the problem? Is it overheating? How to find the problem?
    Tags: None
    • PlainBill
      Badcaps Legend
      • Feb 2009
      • 7034
      • USA
      #2
      Re: Aoc Lm727

      Originally posted by anno
      I have a AOC 17 inch lcd monitor, model LM727 with a backlight problem.
      the ccfl lamps goes off after an hour. The Green light stays on and if i look on the screen there is still an image visible , but the lights are off.

      I checked all caps with ESR meter, and they were all good. And i resoldered some things in inverter area. But still the same problem

      What can be the problem? Is it overheating? How to find the problem?
      If the monitor is several years old, I would hazard a guess that one or more of the CCFLs are dying. It could also be overheating. If the timing is consistent, try changing the temperature in the room and see if it has an effect. (Or cover the back to trap the heat CAUTIOUSLY.)

      If you had a schematic of the inverter and an oscilloscope, it would be possible to determine WHY the inverter was shutting down. This would go a long way towards fixing the problem.

      PlainBill
      For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

      Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

        Comment

        • EGuevarae
          Badcaps Legend
          • Nov 2008
          • 1336
          • USA
          #3
          Re: Aoc Lm727

          Originally posted by PlainBill
          If the monitor is several years old, I would hazard a guess that one or more of the CCFLs are dying. It could also be overheating. If the timing is consistent, try changing the temperature in the room and see if it has an effect. (Or cover the back to trap the heat CAUTIOUSLY.)

          If you had a schematic of the inverter and an oscilloscope, it would be possible to determine WHY the inverter was shutting down. This would go a long way towards fixing the problem.

          PlainBill
          I had one of those and one of the lamps were dead. It failed when hot, so PlainBill's suggestion has sense to me.
          There are 10 kind of people in this world: those that understand binary, and those who don't.
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            Comment

            • anno
              Senior Member
              • Sep 2007
              • 140
              • netherlands
              #4
              Re: Aoc Lm727

              okay. I checked the voltage on the IC in the inverter and when the lamps go off, there is still voltage on vcc pin of IC. i think it is indeed the ccfl lamps too. I try with other ccfl lamps . thanks

                Comment

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