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aspir a515 BQ24780 voltage missing

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    aspir a515 BQ24780 voltage missing

    hello i have an acer aspire a515 turns on without battery when i put battery it turns off,
    voltages on bq24780:
    acn: 18.24v
    acp: 18.24v
    CMSRC:18.74v
    ACDRV:18.73v
    ACOK: 0v
    ACDET: 0v
    VCC: 19.16v
    REGN: 0v

    tanks

    #2
    ACDET: 0v
    This is the wrong value to detect the power adapter. Something is wrong here.

    Also,
    acn: 18.24v
    acp: 18.24v
    This voltage should not be present since the ACDRV is not high enough to enable the 2 x DCin mosfets. Remove the battery and check these measurements again. Do you still see this voltage? If yes, then double check the DCin mosfets - one of them is defective - check the 2nd one first.

    Only if the ACDRV voltage is ~25 volts should BOTH of the DCin mosfets enable to supply the ACN/ACP voltages. Otherwise, ACN/ACP should be the battery voltage.

    The charger IC will enable the ACDRV boosted voltage only after ACDET is > 2v4 AND the REGN voltage is ~6 volts. You do not have REGN at the proper voltage. This is fundamental should be immediately available.

    The charger IC could be defective but start with the above checks. Time for lawn care for me...

    PS: Watching Vagabond (Korean) show on Netflix - they filmed a lot in Morocco - looks very nice Years ago, met Tom Sizemore at the Detroit Airport and shot the breeze with him. He mentioned how he was going to film Black Hawk Down in Morocco (Ridley Scott film?) - nice chat with him for a few minutes. He had relatives in Michigan and was here for Christmas holidays.
    Last edited by mon2; 07-07-2024, 11:32 AM.

    Comment


      #3
      tanks mon2, and I hope everything is going well for you
      so the voltages I gave are without battery, and I changed the charger ic with another one that works on another board, same result

      Comment


        #4
        Which model is yours? Check the logic board markings.

        Click image for larger version

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          #5
          A515-54G-75LV
          motherboard : da0zawmb8g0 rev g

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            #6
            See attached. Review the ACDET resistors. They must be able to supply a voltage that is > 2v4. The raw adapter voltage on its own is too high and will kill the charger IC so 2 resistors are used as a voltage divider to lower the threshold voltage to a safe value.

            Most likely the high side resistor is defective or the trace is not making it to the power adapter. So check resistor @ PR31.

            Click image for larger version

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              #7
              PR31: 880k
              PR211: 136k

              Comment


                #8
                this schematic is for the same board?

                Comment


                  #9
                  In my database, yes, this is the schematic. The resistor values are ok. Carefully measure the voltage on each side of the resistor @ PR31. One side must be the adapter voltage of ~19 volts.

                  Share the voltage to ground measurements on PR31.

                  If no voltage, remove all power -> meter in DIODE mode. Short your meter probes and the meter should tone beep. Then place one probe on the PR31 resistor; other meter probe @ PQ1 (first DCin mosfet) - pin 1-2-3 (any one of these is ok). You should hear a tone beep.

                  If no tone beep, touch the other side of the PR31 resistor. One of the sides of PR31 must tone beep. If not, then there is a PCB trace break between PR31 and the main adapter voltage.

                  Note: For this repair, be 100% sure that you only mate the adapter voltage to the proper side of PR31. DO NOT send this high adapter voltage directly to the charger IC.

                  Share a good pic of the PR31 & PR211 area of the logic board for a quick review. It is important that PR31 high side only mates with the power adapter. The common connection between PR31 & PR211 = ~2v4 when all is working.

                  Click image for larger version

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                    #10
                    voltage on pr31 is 19.27v coming from adapter, the other side is 0v
                    I can confirm that all connections are correct and checked.

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                      #11
                      Good. Check the resistance to ground of ACDET. No power during this check. PR31 may be defective but ACDET may be shorted.

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                        #12
                        ACDET: 124k resistance to ground

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                          #13
                          Remove PQ17 and test again. On your logic board, the DCin power connector (PJ2) is defective.

                          When properly mated with the power adapter, the ADP_ID pin should go low and this action will cause the mosfet @ PQ17 to turn OFF. Only when the mosfet @ PQ17 is OFF, will the proper voltage appear at the ACDET pin on the charger IC.

                          Instead, ADP_ID pin is floating and this action causes the resistors @ PR235 & PR230 to build a voltage divider. The voltage presented at pin 2 (GATE) of the mosfet @ PQ17 is high enough for the mosfet to turn ON.

                          When PQ17 is turned ON, the ACDET pin will shorted to ground and this is why you are observing a 0 volts measurement on the ACDET pin. Then the charger IC believes there is no power adapter connected.

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                          Last edited by mon2; 07-07-2024, 03:28 PM.

                          Comment


                            #14
                            DC jack should click when the adaptor is inserted, shorting ADP_ID to ground. You will also hear an audio bleep if that connection is being made. You can manually just short that pin to ground to prove it. The intent is disable the adaptor till it's fully inserted into the jack.

                            First things I check for on any Acer is power button on the keyboard and DC jack. They are stock faults.

                            Comment


                              #15
                              Are you sure REGN is at 0 Volts as per your post#1?

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                                #16
                                hi mon2 sorry yesterday I couldn't finish the work we started, indeed you were right the transistor PQ17 receives a voltage of 9v on its gate and this short circuit with the ground and ACDET, so I removed the transistor and there I have 2.6v on ACDET, but still ACDRV low (18.75v) and ACOK 0v

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                                  #17
                                  Good start. Confirm the details by mcplslg123 from post # 15. Now that ACDET is OK; chip is being powered; REGN must be ~6 volts. Since it is not, the ACDRV voltage is not boosted.

                                  Is this pin soldered in ok?

                                  Remove all power -> meter in resistance mode -> measure the resistance to ground of the REGN pin. If there is an excessive load, this LDO voltage rail will not work. This is a low current power rail and should always be on at 6 volts.

                                  Has this charger IC been replaced? If not, it may be defective and needs to be replaced.

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                                    #18
                                    yes tanks mcplslg123
                                    REGN is 0v,the ic charger still good its working on another board and soldered correctly
                                    resistance to ground of the REGN pin is 50k

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                                      #19
                                      Confirm the capacitor PC118 is present on the board and soldered to this same REGN pin. It is important to support the 6 volt output.

                                      Consider to flux and carefully remove the gate resistor that is on the ACDRV pin at PR105. Do not lose this 4k ohm resistor.

                                      Then power up again and check if REGN (6 volts) and ACDRV (~25 volts) are at their proper voltage. Be sure that the charger IC is well soldered on the board.

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                                        #20
                                        I checked VCC pin (PQ24780) it is not present 0v, so I was going to check its path it comes from the power resistor PR16 which cracked(i dont now how, after change it I have now all the voltage on the IC charger
                                        tanks mon2 ,mcplslg123 and all the community

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