Macbook A1278 820-2327-A Backlight Issue

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  • Keenan_SCR
    Member
    • Sep 2016
    • 19
    • United Kingdom
    #1

    Macbook A1278 820-2327-A Backlight Issue

    I got following readings on the backlight circuit. Magsafe was on, board was out, LVDS cable disconnected. what do you think? fuse has connectivity and from there it goes to q9806 and not distributed from there on how I see it.


    F9800
    pin1 12.53v (PPBUS_G3H)
    pin2 12.53v (PPBUS_S0_LCDBKLT_FUSED)

    Q9701
    pin1 0V (PPVOUT_S0_LCDBKLT_SW)
    pin2 0V (PPVOUT_S0_LCDBKLT_SW)
    pin3 0V (BOOST_FET_CNTL)
    pin4 0V (BOOST_SINK)
    pin5 0V (PPVOUT_S0_LCDBKLT_SW)
    pin6 0V (PPVOUT_S0_LCDBKLT_SW)

    L9701
    pin1 0V (PPVIN_S0_LCDBKLT_BUF)
    pin2 0V (PPVOUT_S0_LCDBKLT_SW)

    D9701
    pin1 0V (PPVOUT_S0_LCDBKLT_SW)
    pin2 0V (PPVOUT_S0_LCDBKLT)

    Q9806
    pin1 0V (PPBUS_S0_LCDBKLT_PWR)
    pin2 0V (PPBUS_S0_LCDBKLT_PWR)
    pin3 9.65V (PPBUS_S0_LCDBKLT_EN_DIV)
    pin4 12.53V (PPBUS_S0_LCDBKLT_FUSED)
    pin5 0V (PPBUS_S0_LCDBKLT_PWR)
    pin6 0V (PPBUS_S0_LCDBKLT_PWR)

    R9730
    pin1 0V (PPVIN_S0_LCDBKLT_BUF)
    pin2 0V (PPBUS_S0_LCDBKLT_PWR)

    Q9702
    pin1 0V GND
    pin2 0V (LVDS_IG_BKL_PWM)
    pin3 0V (BKL_VREF_IN_4V9)
    pin4 0V (BKL_VREF_4V9)
    pin5 0V (BKL_PWR_EN_L)
    pin6 0V (BKL_PWR_EN_L)

    R9700
    pin1 0V (BKL_PWR_EN_L)
    pin2 0V (BKL_VREF_4V9)
    Tags: None
    • Keenan_SCR
      Member
      • Sep 2016
      • 19
      • United Kingdom
      #2
      Re: Macbook A1278 820-2327-A Backlight Issue

      Anyone?

        Comment

        • Bassman59
          New Member
          • Oct 2015
          • 5
          • Netherlands
          #3
          Re: Macbook A1278 820-2327-A Backlight Issue

          Maybe this helps:https://www.dropbox.com/sh/c3j3gwtdj...kNWM-sWva?dl=0

            Comment

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