Acer A715-75G NO POWER

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  • madjid911
    Badcaps Veteran
    • Dec 2016
    • 387
    • France

    #1

    Acer A715-75G NO POWER

    hello, i have an Acer A715-75G FH5VF LA-J861P laptop that won't start, 19V ok 5V ok but no 3V, enable2 (ENLDO_3V5V) 4V5, enable1 0V, can you help me please , I am not an expert, I looked at all the resistors and short-circuit nothing seems abnormal to me.

    I changed the 3V chip (SY8288BRAC) three times but no result, it is well supplied with 19V5 but does not trigger the 3v

    I attach the diagram for those who need it

    Thank you for your help

    (my english is basic sorry)
    Attached Files
  • reformatt
    Badcaps Legend
    • Feb 2020
    • 1403
    • Australia

    #2
    Re: Acer A715-75G NO POWER

    +3VLP (pin 17) voltage? You have an enable for it, so you should get +3V. This powers the EC, which I'm assuming must be working in some fashion to get +5VALWP.

    Check MAINPWON and 3V_EN_R. 3V_EN must be high to get +3VALWP.

    Comment

    • madjid911
      Badcaps Veteran
      • Dec 2016
      • 387
      • France

      #3
      Re: Acer A715-75G NO POWER

      Originally posted by reformatt
      +3VLP (pin 17) voltage? You have an enable for it, so you should get +3V. This powers the EC, which I'm assuming must be working in some fashion to get +5VALWP.

      Check MAINPWON and 3V_EN_R. 3V_EN must be high to get +3VALWP.
      MAINPWON 3V26
      3V_EN_R 0V (RB15 1MOHMS, RB14 1Kohms its ok)
      DB1 mode diode 0V305 ans 0V its ok
      +3VLP (pin 17) 3V27V
      ENLDO_3V5V 4V5 its too high? or normal ? PR301 PR302 and pr301 its ok.

      Thanks

      Comment

      • reformatt
        Badcaps Legend
        • Feb 2020
        • 1403
        • Australia

        #4
        Re: Acer A715-75G NO POWER

        All good so far. Review your power sequence diagram on Pg 5 of the schematic. You will only get +3VALWP after power button on/off.

        Check the power button for +3V and confirm it drops to 0V when pressed. Then confirm whether you have 3V_EN_R go high from the EC.

        Comment

        • madjid911
          Badcaps Veteran
          • Dec 2016
          • 387
          • France

          #5
          Re: Acer A715-75G NO POWER

          Originally posted by reformatt
          All good so far. Review your power sequence diagram on Pg 5 of the schematic. You will only get +3VALWP after power button on/off.

          Check the power button for +3V and confirm it drops to 0V when pressed. Then confirm whether you have 3V_EN_R go high from the EC.
          Hello, yes I had not seen this page 5, now that I press the power button, the laptop starts and restarts constantly, the 3 v is triggered and remains constant.

          before, the chipset was shorted, I changed it and reballed a new one bought on ali express, maybe the soldering is not good I don't know if I received a chipset with lead-free off or with lead so I heated between the two.

          Do you think the chipset is married?

          Thanks

          Comment

          • madjid911
            Badcaps Veteran
            • Dec 2016
            • 387
            • France

            #6
            Re: Acer A715-75G NO POWER

            Originally posted by madjid911
            Hello, yes I had not seen this page 5, now that I press the power button, the laptop starts and restarts constantly, the 3 v is triggered and remains constant.

            before, the chipset was shorted, I changed it and reballed a new one bought on ali express, maybe the soldering is not good I don't know if I received a chipset with lead-free off or with lead so I heated between the two.

            Do you think the chipset is married?

            Thanks
            I heated the new stronger chipset, now it works, thanks for your help

            Comment

            • reformatt
              Badcaps Legend
              • Feb 2020
              • 1403
              • Australia

              #7
              Re: Acer A715-75G NO POWER

              Do I understand you replaced the PCH? No mention of that in your first post.

              If that is what you've done, then you will also need to clean your ME in the BIOS.
              Last edited by reformatt; 02-13-2023, 04:15 PM.

              Comment

              • madjid911
                Badcaps Veteran
                • Dec 2016
                • 387
                • France

                #8
                Re: Acer A715-75G NO POWER

                Originally posted by reformatt
                Do I understand you replaced the PCH? No mention of that in your first post.

                If that is what you've done, then you will also need to clean your ME in the BIOS.
                Yes I had replaced it because it was shorted which had burned the 3v chip

                Comment

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