Announcement

Collapse
No announcement yet.

Acer - N19C2 - MB EH7LW - Sudden death

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Acer - N19C2 - MB EH7LW - Sudden death

    Hello, I got an Acer N19C2 that doesn't show sign of life. It was working properly and died while I was typing. No charging LED.. nothing, so I opened it and I found schematics on this forum,

    https://www.badcaps.net/forum/showth...ighlight=EH7LW

    which is awesome.

    Using my multimeter, I can see 19V on PQB3 but not on PQB4. Does that mean for sure that this Mosfet PQB3 is the problem ?

    Thanks
    Attached Files

    #2
    Re: Acer - N19C2 - MB EH7LW - Sudden death

    https://www.badcaps.net/forum/showthread.php?t=90356
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

    Comment


      #3
      Re: Acer - N19C2 - MB EH7LW - Sudden death

      Thank you. Are you the same Piernov as Rossman forum ?

      Comment


        #4
        Re: Acer - N19C2 - MB EH7LW - Sudden death

        So I have HBP. PRB3 is short to GND. I will try to remove it

        Comment


          #5
          Re: Acer - N19C2 - MB EH7LW - Sudden death

          so I removed PRB3, that's a resistor ? Can I just short it to test?

          Comment


            #6
            Re: Acer - N19C2 - MB EH7LW - Sudden death

            Am I missing something. It doesn't work. Before I create more problem.

            Comment


              #7
              Re: Acer - N19C2 - MB EH7LW - Sudden death

              https://www.badcaps.net/forum/showpo...50&postcount=2
              2.1.2. Short to ground on main power rail
              Most common issue in this case is a short to ground on main power rail caused by a capacitor, and IC, a MOSFET…
              In this case you have to measure *exact* resistance to ground on the main power rail (same point as previously). If it is lower than several kohms there's a short to ground.
              As indicated in the "Begginer's guidelines: what not to do" section, DO NOT inject 19V. Check high-side MOSFETs for short, easiest way is to place one probe on the main power rail and the other probe on each large inductor of the board. If one is lower than 1 ohm, there's a possibility of high-side MOSFET short. If not, you can start injecting voltage *at 1V*, and double check none of the large BGA is warming up. If 1V is not enough, you can start increasing voltage, after making sure none of the large BGA is warming up again.
              Once you find the bad component, remove it, confirm short to ground is gone, and replaced it. Don't apply power to the board if the component is removed without being sure that it'll not cause any harm.
              OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

              Comment


                #8
                Re: Acer - N19C2 - MB EH7LW - Sudden death

                ok, I don't get anything after Mosfet PQB3. Power rail is not shorted. So I'll remove this PQB3
                Attached Files

                Comment


                  #9
                  Re: Acer - N19C2 - MB EH7LW - Sudden death

                  PQB3 could be defective or PQB3 may not be enabled with the proper voltage on the gate.

                  Every mosfet has 3 pins - SOURCE; DRAIN and GATE. Often, to allow for heavy currents through the mosfet (effectively a solid-state relay) - the designers will gang up or group the pins together so they can share the burden.

                  Remove all power / no battery.

                  Check if the mosfet is shorted:

                  Meter in resistance mode (2k is ok).

                  Check the resistance between -

                  SOURCE & DRAIN
                  SOURCE & GATE
                  GATE & DRAIN

                  Post the values.

                  Share the markings on the first mosfet but most likely the details of the pinout are:

                  1-2-3 = SOURCE
                  4 = DRAIN
                  5-6-7-8 = DRAIN

                  You can see the shorts on the PCB layout = copper plane with green solder mask.

                  Comment


                    #10
                    Re: Acer - N19C2 - MB EH7LW - Sudden death

                    Thank you mon2 for you reply, I really appreciate it. Looking at PCB copper, what you describe looks like what I get.

                    IC = B04N03JL00902 (or somthing near...)
                    https://datasheetspdf.com/pdf-file/1...OS/EMB04N03H/1

                    1 to 2 = 0 ohm
                    2 to 3 = 0 ohm
                    1 to 3 = 0 ohm
                    123(source) to 4 (Gate) = 0.589 (black probe on 4)
                    4 (gate) to 5678 (Drain) = open (tried probe on both side)
                    123 to 5678 = 0.475 (black probe on 5678)

                    Thanks
                    Sam
                    Attached Files
                    Last edited by samstown; 01-25-2022, 01:43 PM.

                    Comment


                      #11
                      Re: Acer - N19C2 - MB EH7LW - Sudden death

                      The resistance checks look ok and the mosfet does not appear to be shorted.

                      Place the meter in DC volts mode (use 30V or higher).

                      Carefully, check the voltage on Pin #1 of this mosfet = should match the DC adapter input voltage.

                      Then, carefully check the GATE voltage. Most likely the voltage on the GATE is not high enough to enable the pass through voltage from SOURCE & DRAIN pins.

                      Post the readings.

                      Comment


                        #12
                        Re: Acer - N19C2 - MB EH7LW - Sudden death

                        Thanks.

                        PIN 1,2,3,4 = 0V
                        PIN 5,6,7,8 = 19.45

                        Comment


                          #13
                          Re: Acer - N19C2 - MB EH7LW - Sudden death

                          Originally posted by samstown View Post
                          So I have HBP. PRB3 is short to GND. I will try to remove it
                          Originally posted by samstown View Post
                          ok, I don't get anything after Mosfet PQB3. Power rail is not shorted. So I'll remove this PQB3
                          ???
                          OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                          Comment


                            #14
                            Re: Acer - N19C2 - MB EH7LW - Sudden death

                            PQB4 excelliance B12N03E looks ok, no short between source, drain and gate
                            Last edited by samstown; 01-25-2022, 02:15 PM.

                            Comment


                              #15
                              Re: Acer - N19C2 - MB EH7LW - Sudden death

                              as I get no Volt on PQB3 and PQB4 source, it must be the two caps... but they are not shorted and just to add, nothing get hot
                              Attached Files

                              Comment


                                #16
                                Re: Acer - N19C2 - MB EH7LW - Sudden death

                                Posting the partial parts of the schematic.

                                It will be a good idea to know the voltages on each pin on the charger IC @ PUB1.

                                Remove the battery but attach the official charger. Then carefully check the voltages on the charger IC. Post the readings.
                                Attached Files

                                Comment


                                  #17
                                  Re: Acer - N19C2 - MB EH7LW - Sudden death

                                  Thank you for your help and patience.

                                  Pin not listed = 0

                                  5 = 2.64
                                  9 = 0.30
                                  16 = 0.4
                                  17 = 0.24
                                  19 = 0.24
                                  20 = 0.24
                                  24 = 1.8
                                  25 = 1.03
                                  26 = 0.24
                                  27 = 0.24
                                  28 = 18.86

                                  Comment


                                    #18
                                    Re: Acer - N19C2 - MB EH7LW - Sudden death

                                    See attached.

                                    Can you confirm again that ACDET = 0 volts ?

                                    This is a simple resistor based voltage divider.

                                    Pin # 1 of PRB11 should be the same as the DC adapter voltage.

                                    What is the reading ?

                                    Then the junction between pin # 2 of PRB11 & pin # 1 of PRB13 should be a much lower but safe value for the charger IC to determine if the charger is plugged in or not.

                                    What is the voltage reading between these 2 resistors ?

                                    The voltage should be a value > 0v unless PRB11 is damaged or is missing from the logic board.
                                    Attached Files

                                    Comment


                                      #19
                                      Re: Acer - N19C2 - MB EH7LW - Sudden death

                                      Hello,

                                      Sorry, my mistake was too late... Pin 5 = 0.

                                      ACDET pin 6 = 2.64

                                      Comment


                                        #20
                                        Re: Acer - N19C2 - MB EH7LW - Sudden death

                                        Hello, ACDET = 2.64V, is this a good thing ?

                                        Comment

                                        Working...
                                        X