ASUS FX507v No Power

Collapse
This topic has been answered.
X
X
 
  • Time
  • Show
Clear All
new posts
  • noipi
    Senior Member
    • Aug 2017
    • 69
    • Singapore

    #1

    ASUS FX507v No Power

    I have ASUS laptop FX507 when i plug-in the charger nothing happens or the amperes not even raising up it stays to 19.5v(SETTINGS). I decided to disassemble the back case to check the voltages first. I found out that when i test the current sensing resistor for voltage it was fluctuating voltages(3volts to 5v then loop), i checked the voltages of the BQ24800 Battery Charge Controller:..i started with the pin 1 and the results are:
    1. 3.5v to 3.9v
    2. 3.5v-3.9v
    3. 0.3v-1.4v
    4. 0.3v-1.2v
    5. 0v
    6. 2.6v
    7. 0v
    8. 0v
    9. 1.6v
    10. 0v
    11. 0.04v-1.1v
    12. 0.2v- 1.2v
    13. 0.2v
    14. 6v
    15. 0v
    16. 0v
    17. 0.2v
    18. 0.2v
    19. 0.2v
    20. 0.2v
    21. 0.2v-0.9v
    22. 0v
    23. 0v
    24. 6v
    25. 6v
    26. 0.2v
    27. 0.2v
    28. 19.5v

    i Need help, Any idea before i change anything or i suspect the charging IC to be replace, i test the 1st and 2nd mosfets from chrging pin it is not shorted or leaky.. thank you.
    Attached Files
  • Answer selected by noipi at 04-25-2025, 10:33 PM.
    Dcortest
    Member
    • Oct 2023
    • 33
    • España

    Maybe this can help
    Attached Files

    Comment

    • mon2
      Badcaps Legend
      • Dec 2019
      • 13829
      • Canada

      #2
      ACDRV pin #4 is not boosted to the expected ~25v so there is a fault in the power path.

      The DCin mosfets are still suspects. Remove all power. Meter in resistance mode.

      Measure each of the DCin mosfets:

      source / drain
      source / gate
      gate / drain


      Post each measurement. Start with the 2nd DCin mosfet (as per sticky above on charger circuits by piernov).

      Comment

      • noipi
        Senior Member
        • Aug 2017
        • 69
        • Singapore

        #3
        Originally posted by mon2
        ACDRV pin #4 is not boosted to the expected ~25v so there is a fault in the power path.

        The DCin mosfets are still suspects. Remove all power. Meter in resistance mode.

        Measure each of the DCin mosfets:

        source / drain
        source / gate
        gate / drain


        Post each measurement. Start with the 2nd DCin mosfet (as per sticky above on charger circuits by piernov).
        thank you for the very fast reply..i will test today what you mention. i will update later today.

        Comment

        • mcplslg123
          Badcaps Legend
          • Jun 2015
          • 7262
          • india

          #4
          Resistance to GND on Current Sensing Resistor?

          Comment

          • noipi
            Senior Member
            • Aug 2017
            • 69
            • Singapore

            #5
            Originally posted by mon2
            ACDRV pin #4 is not boosted to the expected ~25v so there is a fault in the power path.

            The DCin mosfets are still suspects. Remove all power. Meter in resistance mode.

            Measure each of the DCin mosfets:

            source / drain
            source / gate
            gate / drain


            Post each measurement. Start with the 2nd DCin mosfet (as per sticky above on charger circuits by piernov).
            Both DC-in MOSFET first and second got high resistance ranging Kohms to Mohms when reading for source/gate ; gate/drain. no low resistance got from this side and around the Charging ic mosfets..

            Comment

            • noipi
              Senior Member
              • Aug 2017
              • 69
              • Singapore

              #6
              Originally posted by mcplslg123
              Resistance to GND on Current Sensing Resistor?
              i try to read the resistance to ground on Current sensing resistor is 20Mohms, seems to be good.

              Comment

              • noipi
                Senior Member
                • Aug 2017
                • 69
                • Singapore

                #7
                this time trying to test all mosfets and capacitors that is shorted...motherboards seems so clean no sign of burnt or bad components...still checking this time.

                Comment

                • mon2
                  Badcaps Legend
                  • Dec 2019
                  • 13829
                  • Canada

                  #8
                  first and second got high resistance ranging Kohms to Mohm
                  post the requested measurements.

                  Comment

                  • noipi
                    Senior Member
                    • Aug 2017
                    • 69
                    • Singapore

                    #9
                    here is the Readings of the DCIN mosfets before the Current Sensing resistor

                    the first dcin mosfet measure by resistance mode:
                    source/drain 8.8Mohms (probe RED BLK)
                    source/gate 1.3Mohms (probe RED / BLK)
                    gate/drain 14.34Mohms (probe RED / BLK)

                    the 2nd DCIN mosfet measure:
                    source/drain 7.8Mohms (probe RED BLK)
                    source/gate 1.3Mohms (probe RED / BLK)
                    gate/drain 14.17Mohms (probe RED / BLK)​

                    Comment

                    • noipi
                      Senior Member
                      • Aug 2017
                      • 69
                      • Singapore

                      #10
                      tried to find SCHEMATIC diagram or boardview but i cannot see.
                      Attached Files

                      Comment

                      • Dcortest
                        Member
                        • Oct 2023
                        • 33
                        • España

                        #11
                        Maybe this can help
                        Attached Files

                        Comment

                        • noipi
                          Senior Member
                          • Aug 2017
                          • 69
                          • Singapore

                          #12
                          thank you Dcortest

                          Comment

                          • noipi
                            Senior Member
                            • Aug 2017
                            • 69
                            • Singapore

                            #13
                            Thank you to all for the help, specially to Dcortest for the Boardview that really solve the circuit. i change the 2 mosfets that are P-mosfet and N-mostfet connected to the line of Charging IC.
                            Attached Files

                            Comment

                            Related Topics

                            Collapse

                            Working...