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  1. #1
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    820-00923-A BKLT_EN_R missing

    Hi all,

    I need some help.
    I received Macbook pro A1706 820-00923-A from customer that was water damage.
    After open it there was a liquid damage around lcd connector. I clean it and measure but there is no short.
    Tried to turn it on but got blank display but the fan spin and the keyboard backlight is on so i think it only has problem with backlight or display.
    So later i measure J8500 port:
    PPVOUT_S0_LCDBKLT = 0v
    PP3V3_S0SW_LCD = 3,2v
    PP5V_S0SW_LCD = 5v

    So i measure R8442 near Backlight ic and found out there is no Voltage on BKLT_EN_R.
    The BKLT_EN_R goes straight to CPU. does it means that CPU is fail or am i missing something.

    Really appreciate for the help.
    Last edited by kingskie; 01-08-2020 at 09:33 AM.

  2. #2
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    Re: 820-00923-A BKLT_EN_R missing

    Not sure on this model, but other Macs need to have comms with the display established before backlight is enabled.
    Check the comms lines to see if there's activity

  3. #3
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    Re: 820-00923-A BKLT_EN_R missing

    Quote Originally Posted by sargfowler [Only Registered and Activated Users Can See Links. Click Here To Register...]
    Not sure on this model, but other Macs need to have comms with the display established before backlight is enabled.
    Check the comms lines to see if there's activity
    ok bro, i will check again with lcd plugged

  4. #4
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    Re: 820-00923-A BKLT_EN_R missing

    after i plugged the lcd still not getting any voltage for BKLT_EN_R.
    now i am looking for the source as you can see in the picture that
    LCDBKLT_EN_L is 12.9V
    PPVIN_S0SW_LCDBKLT_R is 13V
    but i get 0V on PPVIN_S0SW_BKLT

    so does it mean that the main problem is Q8400 mosfet?

    really need help from the experts here.

    [Only Registered and Activated Users Can See Links. Click Here To Register...]
    Last edited by kingskie; 01-09-2020 at 01:54 AM.

  5. #5
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    Re: 820-00923-A BKLT_EN_R missing

    can somebody help please

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    Re: 820-00923-A BKLT_EN_R missing

    Liquid around LCD connector? Then also probably liquid to CPU power supplies. Power + trackpad + fan + no-video + no USB activity + liquid to CPU power area = dead CPU 99% of the time. Exception would be if external video works, but even then, the eGPU is likely toast. RIP this board.

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    Re: 820-00923-A BKLT_EN_R missing

    Quote Originally Posted by sjword [Only Registered and Activated Users Can See Links. Click Here To Register...]
    Liquid around LCD connector? Then also probably liquid to CPU power supplies. Power + trackpad + fan + no-video + no USB activity + liquid to CPU power area = dead CPU 99% of the time. Exception would be if external video works, but even then, the eGPU is likely toast. RIP this board.
    Does it mean that it would not be useful if i try to replace mosfet or backlight ic?

  8. #8
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    Re: 820-00923-A BKLT_EN_R missing

    You can if it will make you feel better but it won't do anything. Liquid to the top-edge of 00239/00923/etc is catastrophic.

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    Re: 820-00923-A BKLT_EN_R missing

    Of you find damage to the pins on the TCon board or the display connector or logic board socket then it is toast.

  10. #10
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    Re: 820-00923-A BKLT_EN_R missing

    sigh, why apple design this board if it is not repairable...
    thanks for all the help. i will return this macbook to customer now.

 

 

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