Macbook Pro M1 820-02100

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  • Comp_Pro
    Member
    • Jun 2020
    • 33
    • USA

    #1

    Macbook Pro M1 820-02100

    Hello,

    M1 Macbook Pro with 820-02100 board. Came in for liquid damage. Most of the liquid damage was located around UP800 backlight IC. Other than that not much other damage on the board. Computer turns on but shows no display. Originally I could get an image out of the HDMI port but now I only get a quick flicker when closing the lid and then the image disappears from the external monitor. In the brief moment I can see an image I do see the login screen. I tried re flowing and replacing UP800 with no luck. Do not see any shorts or other damaged components. BL_PWR_EN Is showing 1.22V but still no power light. Should be this 3V? Computer seems alive and well except for the display not having any backlight. Any ideas you guys could throw my way please?
  • spidertnt
    Member
    • Jul 2016
    • 34
    • Canada

    #2
    worth checking angle sensor

    Comment

    • Comp_Pro
      Member
      • Jun 2020
      • 33
      • USA

      #3
      So if I understand correctly, it's not possible to simply reset the existing angle sensor correct? A new one must be installed and programmed in order for it to work?

      Comment

      • spidertnt
        Member
        • Jul 2016
        • 34
        • Canada

        #4
        Are you saying the sensor has damage ? yes they need programming

        Comment

        • mon2
          Badcaps Legend
          • Dec 2019
          • 14112
          • Canada

          #5
          See attached. The BL_PWR_EN is 1v2 when active so your measurement shows the correct voltage to enable the backlight circuit.

          1) Confirm that the same voltage is present on each side of RP873 (smd resistor @ 0 ohms).

          2) Measure the voltage to ground of PPVOUT_LUXE @ CP830 or similar large capacitor. If the voltage is not a boosted voltage for the backlight -> power down -> meter in resistance mode -> check the resistance to ground at the same test point of CP830 (to check for any possible shorted capacitor, etc.).

          3) Carefully, measure the voltage to ground of the following points of interest:

          I2C_LUXE_DEBUG_SCL
          I2C_LUXE_DEBUG_SDA

          SPMI_DISP_BKLT_CLK
          SPMI_DISP_BKLT_SDA

          PPBUS_AON_LUXE


          Post each measurement.
          Attached Files

          Comment

          • Comp_Pro
            Member
            • Jun 2020
            • 33
            • USA

            #6
            Thank you much for the valuable input. I'm not sure if the angle sensor is damaged or not, but my guess is no as I just discovered that the display actually does have an image but just doesn't have any backlight. I would imagine if the angle sensor was the issue the screen would not be turning on either correct?

            Thank you mon2. Here are the measurements I took per your indications:

            RP873: All good, voltage on both sides of resistor.
            PPVOUT_LUXE: 0V Diode mode 0.490 Diode mode with display removed: O.L.
            I2C_LUXE_DEBUG_SCL 0.362
            I2C_LUXE_DEBUG_SDA 0.365
            SPMI_DISP_BKLT_CLK 0.278
            SPMI_DISP_BKLT_SDA​ 0.275 <-Did you mean SPMI_DISP_BKLT_DATA?

            I wonder if I got a bad/fake IC or maybe damaged it during install. Curious to try another.

            Comment

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