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Alienware 15 R3 Motherboard Issues Help Plz!

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    Alienware 15 R3 Motherboard Issues Help Plz!

    Hi, I have an Alienware 15 R3 that I just bought a new motherboard for from ebay.. I have been trying to figure out this issue for 2 weeks already and I've decided I need help from the pros.

    Laptop specifics:

    Model : Alienware 15 R3

    CPU : i7 6820HK
    GPU : Nvidia GTX 1080 Max Q
    RAM : 16GB PC4-19200 (8GB x 2)
    STOR : 256GB M.2 SSD + 1TB HDD

    Motherboard : Compal LA-D753P Rev 1.0

    Problem : The laptop runs fine with most things, even GPU/CPU stress tests seem to run without problems for extended periods of time. BUT the laptop just shuts off when I run games. I undervolted the CPU and GPU which helped, some games run fine now, others wont even start.. About 25% of the time when the laptop shuts off unexpectedly the AC adapter also shuts off (blue light ring goes out until power cycled). I have tried everything possible on the software side, there has to be a hardware issue of some kind. The only thing I have been able to find by visual inspection is there is one (of a pair) of 100uF 25V capacitors that has a dent in the top. Is there any chance that the dented capacitor could be the cause of this? I will attach a picture.
    I have already bought a new 240w adapter but that made no difference from the old one. Another thing that may be relevant is the computer originally had a GTX 1070 with i7 7700HQ, I replaced the board and am using the heatsink from the original configuration. I don't believe it is a heat problem though because I setup remote monitoring with hwinfo64 on another laptop and when it shuts off from the games it doesn't like, the GPU and CPU temps are usually very low, under 80C - sometimes around 60C.. And the same games work every time, as well the same other games cause it to shut off before they even finish loading. I have tested the cpu and gpu with every stress test I know of, those never cause it to shut off. Except for Catzilla, it shuts off every time right when the cat shoots the laser from its eyes. No matter what resolution its set to. And on the other hand since undervolting I can run Red Dead Redemption 2 at 1080p with everything maxed out and it has no problem running it. Is there any chance that replacing that cap that is damaged would solve everything? or is that pipe dreaming?

    I apologize for the long post, I'm just trying not to leave anything out that may be useful.

    Thanks everyone for your time and knowledge, I appreciate you!!

    -ZK

    --Edit-- One more detail, I doubt its significant but I am running the laptop as a desktop, no battery.. (it swelled)
    Attached Files
    Last edited by z32KRAzY; 08-07-2022, 06:09 AM. Reason: Forgot a detail

    #2
    Re: Alienware 15 R3 Motherboard Issues Help Plz!

    Remove all power. Meter in resistance mode.

    Measure the resistance across the 2 pins of these dented capacitors. Post their readings and the scale used on your meter.

    Comment


      #3
      Re: Alienware 15 R3 Motherboard Issues Help Plz!

      I would start checking for cold solder joints in the DC-IN circuit. Challenged cracked ferrite beads a few times causing random shutdowns, especially under load. Also a detailed inspection of the DC-Jack cable would be a idea. Check for bad contacts where the cable are soldered.
      FairRepair on YouTube

      Comment


        #4
        Re: Alienware 15 R3 Motherboard Issues Help Plz!

        Originally posted by mon2 View Post
        Remove all power. Meter in resistance mode.

        Measure the resistance across the 2 pins of these dented capacitors. Post their readings and the scale used on your meter.

        Okay I checked them with a Fluke 177, the 2 caps both gave the same readings, I assume they are connected in parallel.. On auto range it used 600K Ohms and the reading started at 180 and continuously dropped. I also tried 3 manual ranges, @60M - 0.002, @600K - started at ~14 and increased to 30 in a few seconds still rising, @6K - started at ~0.6 and increased until it hit OL after a second or so.

        I'm not sure how to interpret these readings, I am assuming this is showing that the cap is behaving as expected?

        Thanks for your help and suggestions, I will happily try anything I have the tools to test..

        Comment


          #5
          Re: Alienware 15 R3 Motherboard Issues Help Plz!

          Originally posted by Sephir0th View Post
          I would start checking for cold solder joints in the DC-IN circuit. Challenged cracked ferrite beads a few times causing random shutdowns, especially under load. Also a detailed inspection of the DC-Jack cable would be a idea. Check for bad contacts where the cable are soldered.
          Hi, I'm trying to figure these ones out.. By cold solder joints on the DC in, do you mean on the DC-IN connector? And the ferrite beads, I'm not even sure which components these would be on the board. I looked at everything in the area of the DC-IN and I couldn't see anything that looked cracked, I'm not really sure what I'm looking for though.. I am going to pull the motherboard out right now so I can inspect the DC-Jack cable. Will update with my findings.. Thanks for your suggestions and taking the time to help!

          Comment


            #6
            Re: Alienware 15 R3 Motherboard Issues Help Plz!

            Originally posted by Sephir0th View Post
            I would start checking for cold solder joints in the DC-IN circuit. Challenged cracked ferrite beads a few times causing random shutdowns, especially under load. Also a detailed inspection of the DC-Jack cable would be a idea. Check for bad contacts where the cable are soldered.
            So I couldn't see any faults with the DC cable, but I didn't want to unwrap it, so I just ordered a new one, it'll be here tomorrow. I couldn't see any cold solder joints on the DC-IN connector but I reflowed the solder to the pins just to be sure. I haven't reassembled it yet though. I also used my boroscope camera (closest thing I have to an electronics microscope) to get a better close up look at the board and components, but I didn't see anything that stood out as damaged to me. Thanks again. Please if you have any more suggestions I would really appreciate them. 🙂

            Comment


              #7
              Re: Alienware 15 R3 Motherboard Issues Help Plz!

              Yes yes, rule out all possibilities. Everything you can think off. A new DC-Jack cable might rule it out for sure. I'm pretty interested in the result although it would be hard to source more ideas if it doesn't solve the issue...
              FairRepair on YouTube

              Comment


                #8
                Re: Alienware 15 R3 Motherboard Issues Help Plz!

                Replace the battery first. Some charger designs utilise power from the battery when the system power requirements exceed that of the adaptor. Given your adaptor shuts off, that is the likely scenario.

                Comment


                  #9
                  Re: Alienware 15 R3 Motherboard Issues Help Plz!

                  Originally posted by reformatt View Post
                  Replace the battery first. Some charger designs utilise power from the battery when the system power requirements exceed that of the adaptor. Given your adaptor shuts off, that is the likely scenario.
                  I had considered that, but my original motherboard was able to run without a battery without issue. However this is a different GPU and CPU than the original board so its possible. I just ordered one so we'll see if that's the cause. Thank you for your input!

                  Comment


                    #10
                    Re: Alienware 15 R3 Motherboard Issues Help Plz!

                    Hey guys, that DC cable arrives today and the battery tomorrow.. But I just noticed something, I took off the heatsink to inspect the components that were under it and I noticed this.. I think it's a power inductor if google got me to the right conclusion. Would this be the cause?? I hope that is the culprit, could one of you that knows more than I please let me know if that seems likely? Thank you all!
                    Z
                    Attached Files

                    Comment


                      #11
                      Re: Alienware 15 R3 Motherboard Issues Help Plz!

                      Forget about it. Even when it has a slight crack it should be still full functional.
                      FairRepair on YouTube

                      Comment


                        #12
                        Re: Alienware 15 R3 Motherboard Issues Help Plz!

                        Originally posted by Sephir0th View Post
                        Forget about it. Even when it has a slight crack it should be still full functional.
                        Awe that's disappointing, I thought that was going to be it for sure.. The dc cable arrived, I'll swap it out and reassemble and see if there's any change shortly. I will post my results of course..

                        Comment


                          #13
                          Re: Alienware 15 R3 Motherboard Issues Help Plz!

                          Well guys I want to say thank you to everyone who provided suggestions! I am not 100% sure yet what was the cause, but I will narrow it down and post the known solution. I switched the dc port cable, reflowed the dc-in connector on the motherboard, and got a battery since I last tested. And now it does not shut off, so one of those was the cause. I suspect it was the lack of battery, but I will narrow it down to provide my verified solution. Now I have the problem that the cheap battery I bought from amazon doesnt charge. It just shows 6% available (plugged in) when I hover over the battery icon, I have tried uninstalling the ac adapter and battery drivers but that didn't change anything.. If I can't get the battery to charge its not a huge deal, I'll just return it to amazon. THANK YOU GUYS AGAIN!! I seriously love this forum!

                          Comment


                            #14
                            Re: Alienware 15 R3 Motherboard Issues Help Plz!

                            Locate the charger IC on the logic board.

                            Post the smd markings. Likely a part from TI (not the rapper) with BQ....

                            It should be near the dc adapter connector.

                            Comment


                              #15
                              Re: Alienware 15 R3 Motherboard Issues Help Plz!

                              Originally posted by mon2 View Post
                              Locate the charger IC on the logic board.

                              Post the smd markings. Likely a part from TI (not the rapper) with BQ....

                              It should be near the dc adapter connector.
                              Okay I found it.. It's marked with:

                              BQ
                              24780S
                              TI 77I(?)
                              AJS8

                              Not sure about the last character in the third line, I'll attach a picture of it..

                              Do you think there's something wrong with the charging circuit? I assumed it wasn't charging just because it's a cheap aftermarket battery..
                              Thanks again!!
                              Attached Files
                              Last edited by z32KRAzY; 08-11-2022, 11:21 PM.

                              Comment


                                #16
                                Re: Alienware 15 R3 Motherboard Issues Help Plz!

                                Hey guys, I guess it is the charging circuit.. This is a screenshot from ubuntu power statistics, it appears it is trying to charge the battery.. What's going to be the likely problem? That TI chip itself?
                                Thanks..
                                Attached Files

                                Comment


                                  #17
                                  Re: Alienware 15 R3 Motherboard Issues Help Plz!

                                  Yes. This is the charger chip.

                                  With the power adapter and battery connected, very very carefully, measure the voltage on each pin of this IC.

                                  From the voltage readings, we will have a better understanding of what the charger IC is doing.

                                  In many cases, the fault is with a defective 2nd dcin mosfet that is driven by this charger IC. See above sticky on charging circuits and their operation

                                  Comment


                                    #18
                                    Re: Alienware 15 R3 Motherboard Issues Help Plz!

                                    Originally posted by mon2 View Post
                                    Yes. This is the charger chip.

                                    With the power adapter and battery connected, very very carefully, measure the voltage on each pin of this IC.

                                    From the voltage readings, we will have a better understanding of what the charger IC is doing.

                                    In many cases, the fault is with a defective 2nd dcin mosfet that is driven by this charger IC. See above sticky on charging circuits and their operation
                                    Alright I'm on it. I will post back with the results after I test. I'll read that sticky too. Thanks again!

                                    Comment


                                      #19
                                      Re: Alienware 15 R3 Motherboard Issues Help Plz!

                                      Originally posted by mon2 View Post
                                      Yes. This is the charger chip.

                                      With the power adapter and battery connected, very very carefully, measure the voltage on each pin of this IC.

                                      From the voltage readings, we will have a better understanding of what the charger IC is doing.

                                      In many cases, the fault is with a defective 2nd dcin mosfet that is driven by this charger IC. See above sticky on charging circuits and their operation
                                      Okay, that was harder than I expected but I got the voltages of each pin. Here's what I got:

                                      BQ24780S
                                      P1 - 18.9v
                                      P2 - 18.9v
                                      P3 - 19.4v
                                      P4 - 19.45v
                                      P5 - 3.323v
                                      P6 - 2.59v
                                      P7 - 0.00v

                                      P8 - 0.00v
                                      P9 - 0.393v
                                      P10 - 1.060v
                                      P11 - 3.39v
                                      P12 - 3.38v
                                      P13 - 0.444v
                                      P14 - 0.54v

                                      P15 - 0.034v
                                      P16 - 3.416v
                                      P17 - 10.2v
                                      P18 - 10.2v
                                      P19 - 10.2v
                                      P20 - 10.2v
                                      P21 - 1.495v

                                      P22 - 0.00v
                                      P23 - 0.00v
                                      P24 - 6.017v
                                      P25 - 9.94v
                                      P26 - 10.07v
                                      P27 - 10.2v
                                      P28 - 19.2v

                                      If anything sounds wrong let me know and I'll check it again.. Thanks!! Oh and the battery is down to 0% now, might help to know?
                                      Last edited by z32KRAzY; 08-13-2022, 03:00 AM.

                                      Comment


                                        #20
                                        Re: Alienware 15 R3 Motherboard Issues Help Plz!

                                        Nobody noticed? From measurements one of your DC-IN MOSFET is internal shorted sind ACDRV doesn't reach 25V. Should be easy to solve from here.
                                        FairRepair on YouTube

                                        Comment

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