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A2159 Touch bar No backlight

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    A2159 Touch bar No backlight

    I have MacBook Pro A2159 EMC 3301 board 820-01598 that Touch bar is working but with No Backlight, I replaced it with a new one , have the same issue
    Checked both connecters J5110 , J5100 from board side and from Touchbar side , it have no issue
    so if anyone know how to make sure backlight voltage is exist , and which pin?

    #2
    Re: A2159 Touch bar No backlight

    From a review of the signal names, this is a single lane MIPI DSI design.

    So you have your

    MIPI DATA_P/DATA_N lanes - the pair = single lane design
    MIPI CLK_P/CLK_N lanes - always required on every MIPI design

    The above are used to configure and stream out the display data.

    Since you can see the display data - the above MIPI lines are ok.

    Backlight will be a power rail also present on the same connector.

    Check PP3V3_G3HSW_DFR on J5110 and post the voltage measurement. This voltage rail is passing through a load switch @ U5111. This load switch is enabled through pin # 1.

    Do also check if the load switch is being enabled or not.

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      #3
      Re: A2159 Touch bar No backlight

      PP3V3_G3HSW_DFR on J5110 pin 18,20,22 is 3.3V
      I couldn't check Voltage on U5111 but R5110 is 7.5kΩ

      side question: can I power on board outside frame without power button?

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