dv51113us LCD back-light controller not working properly

Discussion in 'Mobile Technology' started by BitFracture, Jan 17, 2013.

  1. BitFracture

    BitFracture Geek Trainee

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    I have an HP dv51113us laptop with an interesting problem with the back-light. When the PC has booted windows, it will keep the back-light on for a maximum of 5 seconds, then turn it off. Sometimes it will come on for a few seconds and go off at completely random intervals. I see no patterns other than it almost always being fine before the drivers are initialized.
    I have the latest drivers and bios. My inverter works perfectly as far as I can tell, and the bulb is sitting out of the display, seems to be working fine too. The inverter shows an input voltage in milivolts when the light is off, and 30v when it is working.
    Does anyone know how I should approach this? I have ran out of fixes I know how to perform.

    Thank you for any help!
     
  2. BitFracture

    BitFracture Geek Trainee

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    I apologize, I had a few computer problems of my own.

    The CCFL lamp is fine, I can solder myself if need be. However, after narrowing down the problem to the inverter, and after replacing both the inverter and video cable, the problem persists. More info though, if I ground the inverter pin1 (input) to the chassis, the inverter will work fine for about 2 minutes. By connecting the pins 1 and 2 (input) on the inverter with a bridge, the machine turns on the back-light before initializing video, but it works seamlessly. I am going with the conclusion that the video controller is bad, and this custom modification is the only way this system is going to back-light properly.
    I don't see any other side affects of this modification, and my customer is happy that he didn't need to buy a new laptop. Custom repairs are my specialty.

    If you know a fix to this other than my solder bridge, please let me know. Thank you so much for your response.
     

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