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Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

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    Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

    Hi all, First post here
    Decided to up my game in electronics repair, and bought this dead notebook as learning material. The guy had already sold the screen assembly and ssd, I got the rest very cheap. Told me that he left it charging, and a power surge killed the non original USB C charger in use, and the note.

    Schematics seem to be non existent, only sites I`ve found with reference to this model are just trying to serve me malware.

    Been probing arround to reverse engineer the board, and made some progress:

    - USB PD controller chip (TI TPS65994 AC, very small flip chip bga) is working, it can switch power acording to de usb port in use, and pass it to the battery charger.
    - Battery controller (ISL9241) seem to be ok. Without battery plugged, it converts whatever comes from usb to 8.4V base Vsys, present in several parts of the board. With the battery, it pases Vbatt to Vsys.
    - All the other power converters on board are inactive, except one near the bios chip that has 0ohm to ground. The 4 caps beside it are grounded on both sides. There`s some kind of mosfet beside them, that gets a little warm with power present; not the caps. The short is not a big one, some kind of logic is controlling it. With a proper 65w usb C power adapter is about 20ma. With a dumb usb A phone charger at 5v is arround 200ma, and I can hear some coil whine.

    So my question here is for help identifing the suspected component. Searching for the markings "AWSDPK" bring no results. What should be my next steps? I`m not sure if it is usefull trying to desolder it if i can`t find a replacement.

    I include high resolution images of the board, and a detail of the problem area.

    Thank for your help
    Attached Files

    #2
    Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

    Is the coil meant for 1.05V PCH Power?? If yes, then PCH part of the SOC is dead. The IC connected to coil is not readable in image posted by you. Google the IC number and findout whether it stands for what i fear.

    Comment


      #3
      Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

      Please help me identify it. I'm just learning this. I'm more used to desktop hardware; this laptop stuff looks very different.

      I can't find any chip that look like a traditional PCH. is the ITE part? seems to be an input controller.

      I don't know what this power circuit is suposed to feed. It's output seems to go to an inner plane of the board. The suspected IC is marked "AWSDPK"; google returns nothing. There's another one with the same markings feeding the memory. Seems to be a dual mosfet with integrated digital control

      Comment


        #4
        Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

        https://www.badcaps.net/forum/showpo...1&postcount=12
        OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

        Comment


          #5
          Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

          Thanks!
          That helped a lot. Theres no datasheet for this piece, but a I could see the pinout on the schematics linked

          Originally posted by mcplslg123 View Post
          Is the coil meant for 1.05V PCH Power?? If yes, then PCH part of the SOC is dead. The IC connected to coil is not readable in image posted by you. Google the IC number and findout whether it stands for what i fear.
          Now I understand what you are saying: PCH is integrated in the cpu, so it is quite possible the cpu is toast, and there's no problem on the caps or VRM?
          How could I test that? Remove vrm parts, and if the short is still there, the problem is the PCH?

          Comment


            #6
            Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

            Remove all power. Meter in lowest resistance scale.

            Check the resistance to ground of the Vcore (CPU) rail. Post the measurement.

            Often, the CPUs, being current pigs, will have their power rail split across multiple buck regulators. Respectively, look for multiple coils in the vicinity of the CPU IC. Each such coil takes turn powering the CPU so that not one is burdened with the task and will run cooler from this duty cycle.

            Being an Asus model, you probably do not have schematics so just look for the cluster of grey coils (3-4) that are working to power the CPU.

            If the resistance is too low, the CPU could be toast. Wish to note again that on a macbook pro a few weeks ago, the CPU rail was at 1 ohm yet the CPU was working fine.

            Comment


              #7
              Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

              There are 3 power phases feeding in to the cpu with 48ohm that must be Vcore
              Another circuit with dual coils at 10ohm also feed it.
              And the third power circuit in the area is the one shorted. Goes into an inner board plane

              Attached is all coils readings and locations
              Attached Files

              Comment


                #8
                Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                Focus on the one with 0 ohm resistance.

                Any chance you have a thermal camera? An adjustable power supply? (Always to be used at low voltage of 0v8 to 1v0 max).

                See if you can find any discolored capacitor in this area.

                Comment


                  #9
                  Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                  I wish I had a thermal camera
                  I'm not very well equiped for this tipe of job. I have a soldering station, and a hot plate where i'm very succesfull at building things with smd components. Need to get a hot air station asap.

                  Tried a variety of usb power sources on the usb C plug, and the only one that caused some meaningfull power draw was a dumb 5v basic phone charger. In that condition, IPA evaporated quicker from the menctioned coil and mosfet IC.
                  Don't have a propper lab power supply, but some generic CC/CV boards. Minimum Volts is suposed to be 1.25V, but maybe it can be used given it has CC limit?

                  Meanwhile, had a look into intel 11th gen datasheet, and found this:
                  the processor has one main voltage rail (VCCIN), the PCH has one main voltage rail (VccIN_AUX) and a voltage rail for the memory interface (VDD2).
                  The maximum limits for those rails are:
                  VCCIN= 2V 65A
                  VccIN_AUX= 1.8V 27A
                  VDD2= 1.115V 1.5A

                  So maybe it's safe to assume the faulty power rail is the one for the memory controller part?
                  Anyway, that info leave me in the same spot: If that part is fried the cpu is dead

                  Comment


                    #10
                    Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                    It is ok..after too many videos and readings, we finally ordered a thermal camera today - chose the Qianli X 3D - which was recommended by TCRS youtube video. The IR sensor inside this camera is the best at affordable pricing.

                    Good observation using the IPA!!

                    What are the markings of the mosfet that is heating up ?

                    Remove all power -> meter in resistance mode -> check the resistance across this same mosfet,

                    source & drain
                    source & gate
                    gate & drain

                    Very likely, this mosfet is shorted / defective.

                    Do you have hot air tools to remove it ? Suggest to flux it and then hot air with low air pressure so that other parts do not go flying. If you are planning to service more in the future, it will be a good investment.

                    We have the BEST 863 (going from memory) and is a clone of the QUICK series. Supports upto 550 C which is nice to have for some of the multilayer PCBs. Aliexpress has these all over the website.

                    PS: Do not worry about the power supply for injection - the power supply needs to be lower to be safe. This is a just-in-case some mosfet is leaking and will allow for your higher voltage to reach the lower voltage rails of the CPU and then it is for sure, game over.

                    Comment


                      #11
                      Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                      Sweet camera that one!
                      Unfortunately i have to add it to a long list of desired expensive tools. I'm not a pro, just a guy that enjoys the pleasure of giving a second life to things others have discarded.

                      The mosfet is an IC that piernov helped to identify earlier in the tread. It's a dual mosfet with integrated controller, so I have no acces to the gates. Corresponding product code is SY8288RAC.
                      Measuring resistance between source and drain is all over the place. Constantly ramping, and reaching different values depending on meter scale. Stabilizes at about 19k in 40k scale, and about 90k in 400k scale. Oposite polarity never sabilize. I guess near components mess the reading.
                      Diode mode shows both sides at 0.375V

                      Tried desoldering some caps with the iron and a blob of solder, but no luck.
                      I definitely need hot air. Gona take a while to get it, local stores have few and expensive options; my best source is aliexpress.

                      Comment


                        #12
                        Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                        Just wanted to update that I finally got my hot air station.
                        Desoldered the suspecting vrm and caps, and the short is still there.
                        Following the traces I couls see that theres no more components between this output and the backside of the CPU, so the short must be internal.

                        So I just wanted to say thanks to everyone that helped me in diagnosing the board.
                        This may be the end of the road for this board, but it was a huge learning experience, that was only possible with the help and information available in this wonderfull forum.

                        Thank you guys!

                        PS: With the knowledge and experience gained, I already managed to repair a discarded Macbook pro A1278. Turns out, it was barely usable because a bad accelerometer chip was sending random resets. That was fun to diagnose!

                        Comment


                          #13
                          Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                          inject 1V 5A to that shorted rail and pour ipa on cpu and io part of cpu. i bet that u will see heatspot on io part

                          Comment


                            #14
                            Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                            Originally posted by ktmmotocross View Post
                            inject 1V 5A to that shorted rail and pour ipa on cpu and io part of cpu. i bet that u will see heatspot on io part
                            haha, I like that. Without some sparks, It's not a good ending

                            Comment


                              #15
                              Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                              Hello!
                              Since there is no schematics i need help from you..
                              @Gorflan or anyone else - i need restistance value from the atachement.
                              Thank you very much!
                              Attached Files

                              Comment


                                #16
                                Re: Asus Zenbook Flip UX363EA killed by a cheap usbc power adapter

                                Originally posted by Legolulu View Post
                                Hello!
                                Since there is no schematics i need help from you..
                                @Gorflan or anyone else - i need restistance value from the atachement.
                                Thank you very much!
                                hi, 125kohm and up mounted in the board

                                Comment


                                  #17
                                  Hello everyone, can somebody help me with the values of circled resistors from photo? I tried to replace ISL9241 with hot air station, i removed the old chip and when i soldered the new one i heard a pop in that area, and laptop now is not turning on. I tried then replacing 3 new ISL chips but wont start anymore! Not sure but maybe a resistor or something got damaged near the ic! Is hard to repair as i don't have a schematic! Thanks!
                                  Attached Files

                                  Comment


                                    #18
                                    If the photo is of your mb,then nothing seems missing to my eyes.

                                    Comment


                                      #19
                                      I ordered a new chip from mouser to try again! Is not about missing them is abut their values , i'm thinking maybe a resistor became faulty because of heat because i herd that pop. Not sure, thanks

                                      Comment


                                        #20
                                        You will have to carefully inspect the ICs where you applied the hot air. Often the pop is due to high heat applied quickly onto an IC that may have had some internal moisture. The high heat causes the ic to crack from the steam buildup or expansion. This is why ics are pre-baked for hours at a low heat temp to draw out the moisture over time. Then the dried ics can be soldered onto a fresh pcb during assembly time. So this ic may have a crack somewhere on its body.

                                        search for ‘popcorn effect in pcb assembly' for more details.

                                        Comment

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