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Macbook Air A1466 820-000165 Fan allways on 6200rpm

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    Macbook Air A1466 820-000165 Fan allways on 6200rpm

    Hello, i have a Macbook Air A1466 820-000165 where the fan is constantly running 6200rpm, as soon as i hit the power button.
    I already tried a different fan, reset of SMC and PRAM. No difference.
    So i measured the voltage on the connector
    1:5V PP5V_S0
    2:1.6V TACH
    3:4.6V Motor Control
    4:0V GND

    I checked HW Monitor temperatures are in the normal range, no missing signals.

    What can i check next?

    #2
    Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

    Measure the voltages on the following:

    SMBUS_SMC_3_SDA
    SMBUS_SMC_3_SCL


    and post the readings.

    Comment


      #3
      Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

      Thank you for the fast reply. Both signals are 3.3V

      Comment


        #4
        Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

        Review this thread:

        https://www.badcaps.net/forum/showthread.php?t=93255

        Comment


          #5
          Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

          Originally posted by Mannislav
          fan is constantly running 6200rpm, as soon as i hit the power button.
          Originally posted by Gabr
          after 10 seconds the fan spin starts to rise and reaches maximum speed
          Completely different problems.
          OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

          Comment


            #6
            Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

            Focus on mosfet @ Q6060. Apply flux and reflow it.

            Confirm the resistance and presence of R6061.

            Confirm the connections in this area to the fan connector.
            Attached Files

            Comment


              #7
              Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

              I already found that thread and switched with a known good one.
              Resistance of the Resistors in this area are right.
              Then i reflowed it as best as possible with the connectors nearby, but no difference.
              I also measured from SMC_FAN_0_CTL to R6061 using a testpoint on the backside near C7601 and i get 400/500KOhm depending on which side of the resistor i measure. But reading the schematics there should be no resistance, since it is a trace on the board. Or am i thinking wrong?

              Comment


                #8
                Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

                Confirm prescence of fan tach using a scope to the SMC. If it’s missing, fan will be driven at full speed.

                Comment


                  #9
                  Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

                  Try another fan.

                  Comment


                    #10
                    Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

                    I already tried another Fan. I have no scope to Check tach but with mac Fan control it displays RPM Signal.
                    Last edited by Mannislav; 06-30-2022, 11:15 PM. Reason: Spelling error

                    Comment


                      #11
                      Re: Macbook Air A1466 820-000165 Fan allways on 6200rpm

                      Fix,change mosfet

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