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820-2936-B - Turn ON and OFF

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  • 820-2936-B - Turn ON and OFF

    Green Light - OK
    PPBUS_G3H - OK
    PP3V42_G3H - OK
    PP5V_S5 - OK
    PP5V_S0 - 2.20v and drop for 0v (turn on and off fan)


  • #2
    is this on-off loop or just on-off once???

    Comment


    • #3
      aprendiz, yes in loop. ON and OFF

      Comment


      • #4
        check R7402....

        Comment


        • #5
          Checked! Looks fine

          Comment


          • #6
            Looks fine? Measure it!
            If R7402 is ok then measure voltage on Y2805 should not exceed 1.6V else clock chip is dead.
            I assume this was a liquid damage?

            Comment


            • menatwork
              menatwork commented
              Editing a comment
              A mean: I measure and is fine! Yes, liquid damage.

          • #7
            if resistance over C7050 doesn't exceed 2.2 to 4 ohms then U2800 is probably dead. so check duke's advice because that is the best way to tell if U2800 is dead. i am also going to guess your liquid damage was on the rim, by either vp0r sensor, thunderbolt area, or smc. even if the clock chip has no corrosion or water on it, just water in that area, it means it is dead..

            Comment


            • #8

              dukefawks larossmann I replaced U2800 and works (fan spin), but i don't backlight.
              Last edited by menatwork; 06-21-2016, 12:48 PM.

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              • #9
                Got image without backlight? Read the sticky post about the backlight applies to 2936 too.

                Comment


                • #10
                  Yes, no image or chime. And yes, the model is 820-2936

                  Comment


                  • #11
                    What is is not?? You say no backlight and now there is no image or chime......
                    Connect a USB mouse and see if it lights up, CPU Vcore present?

                    Comment


                    • #12
                      dukefawks, i have light in the mouse(usb). I will check Vcore

                      Comment


                      • #13
                        Ppcpuvccio_so - 1.05v
                        smc_cpu_isense - 0v
                        ppvoce_so_cpu_ph1 - 0.76v

                        Comment


                        • #14
                          Board is working. Connect a known good LCD and hold a flashlight to the back of the Apple logo to check if there is an image.

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                          • #15
                            Yes, i have folder question mark.
                            Backlight is a problem right now.

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