power ccfl backlight from mains 240v AC?

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  • frosty3907
    Member
    • Sep 2014
    • 30
    • Australia

    #1

    power ccfl backlight from mains 240v AC?

    I've got an old 42 inch backlight array with inverters i was going to hack together into a coffee table infinity table.

    Powering with a 24v 9a adapter and 3.8v to on/off only succeeds in illuminating for two seconds before a shut down, i read about this elsewhere on the site and apparently people had success bypassing a controller IC designated oz*something by applying 2v to pin 1 after lifting it from the PCB, i found oz9982gn on mine but couldn't find solid data on pins or required voltage. I measured it in circuit and at power on it goes to ~150v(?!) And then down to 4.8v steady.

    I tried lifting it and applying a steady 5v but the circuit doesn't complete, pretty sure I'm using the wrong pin.

    Anyway; is there a better way than going ac-dc-ac?
    Can you power the ccfl's directly or with a simple (cheap) adapter from 240v AC?
    Otherwise is there a way I can bypass the protection and cram the 24v into the transformers whether they want it or not?

    Thanks guys
  • kc8adu
    Super Moderator
    • Nov 2003
    • 8832
    • U.S.A!

    #2
    Re: power ccfl backlight from mains 240v AC?

    or your ccfl/inverter has a defect?

    Comment

    • eccerr0r
      Solder Sloth
      • Nov 2012
      • 8701
      • USA

      #3
      Re: power ccfl backlight from mains 240v AC?

      I don't think you can light a CCFL with 240VAC directly mainly because the voltage isn't high enough to strike. Even if you could, you still need the large inductor ballast to make sure it doesn't do thermal runaway.

      Usually when a good fluorescent ballast controller detects that the bulb is missing, it will shutdown to save itself...

      Comment

      • frosty3907
        Member
        • Sep 2014
        • 30
        • Australia

        #4
        Re: power ccfl backlight from mains 240v AC?

        It has 16 lamps, they all light and appear fine.
        Guess this should be moved to TV repair?

        Comment

        • xxxvirus1987xxx
          unlegendary
          • Sep 2014
          • 24
          • philippines

          #5
          Re: power ccfl backlight from mains 240v AC?

          their are only twoo reason for that
          iether bad inverter section.
          or cfl or backlight problem activating the protect sytem to shutdow yung tv unit...
          bypassing the controller for inverter sometime dangerous to other components....
          test all the cfl if it is working fine....use cfl tester improvise etc..
          to confirm if the cfl are realy bad or not....gud luck..
          also try this......
          https://www.badcaps.net/forum/showthread.php?t=10419
          Last edited by xxxvirus1987xxx; 09-14-2014, 10:40 PM.

          Comment

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