Asus x541u vcc core missing

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  • arber1232
    Badcaps Veteran
    • Dec 2019
    • 367
    • Albania

    #1

    Asus x541u vcc core missing

    Hello everybody . I have an Asus laptop that turns on but does not display the screen. I continued with the voltage measurement.19 v is ok 3.3v is ok 1.5 volts in RAm is ok. but in cpu I do not have 1.0v or 1.2v ... how much can the processor have. And the processor was cold ,, .. After some measurements I noticed that PQl8104 was short. I removed it and replaced it with mosfet 6414A I do not know if it is a choice but please tell me .. I put it in the charger I see that the cpu is hot but there is no image. I did the bios that I found in this forum but again the same problem After the voltages in Pl8102 it is 0v and in Pl801 it is 0 v..This laptop has NCP81216A chip. Please tell me what I can do to diagnose the problem. Thank you Asus X541UVK REV 2.0 (1).rar This is board view ....And the FAn not spining . I try to turn of laptop but turn on agin for 2 sec.
    Last edited by arber1232; 12-04-2020, 04:49 AM.
  • emestee
    Badcaps Veteran
    • Dec 2019
    • 228
    • Bulgaria

    #2
    Re: Asus x541u vcc core missing

    Re-test all secondary power rails for short to ground and short to B+. Remove the CPU and power up the board, test voltages and watch for the board turning off.

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    • arber1232
      Badcaps Veteran
      • Dec 2019
      • 367
      • Albania

      #3
      Re: Asus x541u vcc core missing

      I not understan B+ can me explain ?.. And i not cant remove cpu becouse is soldered in board......... measure in ohm these two points minus the camera in the gnd of the laptop and + in PL801 and pl802 Click image for larger version

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      Last edited by arber1232; 12-04-2020, 05:11 AM.

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      • emestee
        Badcaps Veteran
        • Dec 2019
        • 228
        • Bulgaria

        #4
        Re: Asus x541u vcc core missing

        B+ is the main 19v rail.

        0.3 ohm is a short. This plus CPU heating up is not good news. Interrupt the VCORE power line as close to the CPU as you can and measure the voltage on it. If the voltage is normal after you replaced the mosfet, and the mosfet you replaced was the high side switch, then there is a good chance the 19v went straight into the CPU and you now have a donor board...

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        • arber1232
          Badcaps Veteran
          • Dec 2019
          • 367
          • Albania

          #5
          Re: Asus x541u vcc core missing

          the mosfet is ok ... i close line in pl801 and pl802 but the cpu is hott . and voltage is 0.2 v in mosfett

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          • emestee
            Badcaps Veteran
            • Dec 2019
            • 228
            • Bulgaria

            #6
            Re: Asus x541u vcc core missing

            This means there's a short in the CPU and its pulling down the voltage, which is why you should test it by interrupting the VCORE line to verify it. Pull out the coil or some other component in the path to the CPU to verify. However, it does appear that your CPU is dead...

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            • arber1232
              Badcaps Veteran
              • Dec 2019
              • 367
              • Albania

              #7
              Re: Asus x541u vcc core missing

              ok i understand you maybe my cpu is dead . but i not understand when i closed lin in pl801 and pl802 why not have voltage in mosfet ?

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              • emestee
                Badcaps Veteran
                • Dec 2019
                • 228
                • Bulgaria

                #8
                Re: Asus x541u vcc core missing

                I dont know what PL801/802 do. I cant open boardview because im at work.

                What do you mean you "closed" the line? The 0v you're seeing is because the short on the CPU sends the voltage to the ground. This is why I am telling you you need to _disconnect_ the CPU to verify that the voltage goes back to normal when the CPU is disconnected.

                Originally posted by arber1232
                ok i understand you maybe my cpu is dead . but i not understand when i closed lin in pl801 and pl802 why not have voltage in mosfet ?

                Comment

                • arber1232
                  Badcaps Veteran
                  • Dec 2019
                  • 367
                  • Albania

                  #9
                  Re: Asus x541u vcc core missing

                  ok pl801 and 802 are behind the mosfet that supply the processor with voltage. that should give 1.5 volts or less .. when I disconnect these I have no voltage. yes it is logical not to give because the cpu is in shorttt ... In processor i have 1.0 v coming from 2 points pjp 8104 and 8303. when I disconnect these laptops it turns on for a while and turns off .. now I have left only pjp 8303 connected and the cpu heats up a bit. pjp 8104 connect +vccsa and +vcccio_cpu pjp8303 connect +1.0vo and +1.0vsus
                  Last edited by arber1232; 12-04-2020, 06:27 AM.

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                  • arber1232
                    Badcaps Veteran
                    • Dec 2019
                    • 367
                    • Albania

                    #10
                    Re: Asus x541u vcc core missing

                    Originally posted by emestee
                    I dont know what PL801/802 do. I cant open boardview because im at work.

                    What do you mean you "closed" the line? The 0v you're seeing is because the short on the CPU sends the voltage to the ground. This is why I am telling you you need to _disconnect_ the CPU to verify that the voltage goes back to normal when the CPU is disconnected.
                    i mean i cut line

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                    • emestee
                      Badcaps Veteran
                      • Dec 2019
                      • 228
                      • Bulgaria

                      #11
                      Re: Asus x541u vcc core missing

                      Originally posted by arber1232
                      ok pl801 and 802 are behind the mosfet that supply the processor with voltage. that should give 1.5 volts or less .. when I disconnect these I have no voltage. yes it is logical not to give because the cpu is in shorttt ... In processor i have 1.0 v coming from 2 points pjp 8104 and 8303. when I disconnect these laptops it turns on for a while and turns off .. now I have left only pjp 8303 connected and the cpu heats up a bit. pjp 8104 connect +vccsa and +vcccio_cpu pjp8303 connect +1.0vo and +1.0vsus
                      If that's the case, I'd put an oscilloscope probe on mosfet gates. If nothing's there, then check enable signals on the DC-DC converter that feeds it, then the converter itself

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                      • arber1232
                        Badcaps Veteran
                        • Dec 2019
                        • 367
                        • Albania

                        #12
                        Re: Asus x541u vcc core missing

                        The Dc is ok I have 19v in mosfets

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                        • emestee
                          Badcaps Veteran
                          • Dec 2019
                          • 228
                          • Bulgaria

                          #13
                          Re: Asus x541u vcc core missing

                          Originally posted by arber1232
                          The Dc is ok I have 19v in mosfets
                          No, I am asking about the gate control

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                          • arber1232
                            Badcaps Veteran
                            • Dec 2019
                            • 367
                            • Albania

                            #14
                            Re: Asus x541u vcc core missing

                            the gate control not have voltage is 0v .

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                            • mcplslg123
                              Badcaps Legend
                              • Jun 2015
                              • 7262
                              • india

                              #15
                              Re: Asus x541u vcc core missing

                              0.3Ohms on cpu line may not be short as cpu is soldered. +1.8V is present?? Check all pwrgood signals.

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                              • arber1232
                                Badcaps Veteran
                                • Dec 2019
                                • 367
                                • Albania

                                #16
                                Re: Asus x541u vcc core missing

                                pwgrd in ncpe is present is 3.3 v .. Which +1.8 v ?
                                where i find +1.8
                                please can you explain to me a little deeper where i can see all pwrgd and +1.8 v
                                Last edited by arber1232; 12-04-2020, 08:37 AM.

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                                • piernov
                                  Super Moderator
                                  • Jan 2016
                                  • 4435
                                  • France

                                  #17
                                  Re: Asus x541u vcc core missing

                                  CPU VCore should be around 6 ohms to ground.
                                  OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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                                  • arber1232
                                    Badcaps Veteran
                                    • Dec 2019
                                    • 367
                                    • Albania

                                    #18
                                    Re: Asus x541u vcc core missing

                                    Originally posted by piernov
                                    CPU VCore should be around 6 ohms to ground.
                                    IN pl8102 i have 13.6 ohm to ground in pl8101 o have 0.13 ohm this point ore cpu vvcc core ?

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                                    • piernov
                                      Super Moderator
                                      • Jan 2016
                                      • 4435
                                      • France

                                      #19
                                      Re: Asus x541u vcc core missing

                                      PL8101 is iGPU VCore but it should be around the same value than CPU VCore.
                                      OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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                                      • arber1232
                                        Badcaps Veteran
                                        • Dec 2019
                                        • 367
                                        • Albania

                                        #20
                                        Re: Asus x541u vcc core missing

                                        then I have gpu in short

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