Correct motherboard for V3-772G - 747a8G75Makk

Options
juhas
juhas Member Posts: 24

Tinkerer

edited August 2023 in 2019 Archives
Hi all,

The motherboard of my Aspire V3-772G - 747a8G75Makk - model VA73 died, and I need to buy a replacement. After some researching from AliExpress I think the correct MB part number for my machine is NB.M7411.001 (with GT750M gpu), but could someone please confirm this, or correct me if I'm wrong.

I also see that there are motherboards 
NB.M8S11.001 (with GTX760M) and NB.MMB11.001 (with GTX 850M) available for not too much extra money. Are these also compatible with my machine or is it likely that I run into problems with anything other than the original MB model? I'm mainly thinking about possible cooling issues with a more powerful gpu.

Thank you very much in advance!
«13

Answers

  • JackE
    JackE ACE Posts: 44,627 Trailblazer
    Options
    Only one mainboard listed on the specsheet for the v3-772G model part number NB.M8S11.001. Other models may fit and work but not guaranteed. Not sure how the existing mainboard 'died' but a solder-reflow might revive it. Jack E/NJ

    Jack E/NJ

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    Hi Jack and thanks for you reply!

    I wonder why only NB.M8S11.001 is listed for this model. My machine has the GT750M graphics while the mentioned motherboard has GTX760M, so it clearly isn't the same board as my machine originally has.

    By 
    'died' I mean that the machine suddenly just totally stopped working. It doesn't even try to start and even the front led won't lit when the power supply is connected. I found out myself that the power supply is broken, but when I took the machine to a repair shop, they couldn't get it started with a working power supply either. They checked that the power connector is OK and also measured voltages from the motherboard without finding any evident fault. Their conclusion was that replacing the motherboard is the only option.

    Sorry for my ignorance but what does solder-reflow mean?
  • MartinJohn00001
    MartinJohn00001 Member Posts: 636 Seasoned Specialist WiFi Icon
    Options
    @juhas
    Hi, I see that you are trying to buy a motherboard. Kindly contact the below link and you will get further help.
    https://us.answers.acer.com/app/answers/detail/a_id/5969

    Kindly click "YES" to "Did this answer the question" if my answer helped you!      
    Thank you and have a Blessed Day  :3
  • JackE
    JackE ACE Posts: 44,627 Trailblazer
    Options
    Not unusual to have production changes or regional differences from the original specs. The Aliexpress board should probably be OK for you.

    Shown below is the top of the mainboard. It should be similar to yours. The power button board (#10) and its connector (#2) should be carefully examined to make sure they are properly seated. There may also be a spring-loaded normally-off safety interlock switch on the bottom of the mainboard that disconnects power to the mainboard if the bottom cover is removed or misaligned. There may be a molded protrusion inside the bottom cover that presses against this normally-off switch to keep it on when the cover is properly aligned.

    If the power button board and/or safety interlock seem to be OK but still no mainboard power, then as a last resort a solder reflow might resolve the issue. To do a solder reflow, all connectors and replaceable boards are first removed from the mainboard. The stripped mainboard is then placed on an aluminum foil cookie sheet and baked in an oven pre-heated to 425*F for about 15mins.  This is essentially the same solder melt/flow technique that was originally used to afix the integrated circuits and discrete components to the mainboard printed circuit. It should repair any loose or cracked solder joints that may be causing the mainboard failure.

    Jack E/NJ 



    Jack E/NJ

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    MartinJohn, thanks for the link!

    Jack, thanks for the profound explanations! The solder reflow thing seems very interesting. If examining the power board and connector doesn't reveal any fault, It seems that I don't have anything to lose with this motherboard, so might as well try that.

    Juha
  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    Hi,

    I ended up buying a used NB.M7411.001 motherboard from Aliexpress. I replaced it myself and now the machine is generally working, but seems to have some stability issues.
    Now I'm wondering should I update the bios - it has an old 1.05 bios version while the newest version is 1.15. Why I haven't done that yet is because I keep reading about possible problems related to bios updating. Now that I have managed to get the machine somehow working, I really wouldn't like to brick the new 
    motherboard... What would you suggest?

    Juha
  • JackE
    JackE ACE Posts: 44,627 Trailblazer
    Options
    >>> seems to have some stability issues.>>>
    Describe 'stability issues' Jack E/NJ

    Jack E/NJ

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    JackE, thanks for your quick reply and sorry for my not-so-quick response...

    The machine works quite OK in basic use, web browsing, office work, light gaming etc. But when my children try to play their more demanding 3d games, like Subnautica, the machine freezes immediately, already when the game is only loading. In these situations it occasionally also gives a blue screen with Stop Code: Video_Scheduler_Internal_Error.

    Juha






  • JackE
    JackE ACE Posts: 44,627 Trailblazer
    Options
    Open Device Manager. What drivers do you see in DisplayAdapters folder? Jack E/NJ

    Jack E/NJ

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    I see:

    Intel(R) HD Graphics 4600
    NVIDIA GeForce GT 750M
  • JackE
    JackE ACE Posts: 44,627 Trailblazer
    Options
    OK. Might be still on the old Win8.1 drivers . What is the driver version number for each adapter? Jack E/NJ


    Jack E/NJ

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    JackE, many thanks for trying to help me. Unfortunately the question of driver versions became irrelevant... the machine stopped working again. More precisely it doesn't get power.

    When I have the battery removed and the power cord plugged in, the machine doesn't start and no leds are lit, looks like completely dead. However, if I attach the battery, the machine starts and boots normally, but the battery isn't charging.

    I guess that this same thing happened also with the original motherboard, but as there was no charge left in the battery, there was no way of knowing that the machine might still start with battery power.

    I disassembled the machine again and removed the power connector and its cord and measured that they should be ok, so the failure seems to be in the motherboard.

    I wonder what can cause this kind of thing to happen in the first place and then again with a new motherboard. 
  • JackE
    JackE ACE Posts: 44,627 Trailblazer
    Options
    Earlier you said >>>I found out myself that the power supply is broken, but when I took the machine to a repair shop, they couldn't get it started with a working power supply either. They checked that the power connector is OK and also measured voltages from the motherboard without finding any evident fault. Their conclusion was that replacing the motherboard is the only option.>>>

    How did you first come to the conclusion that the power supply was broken? The reason I ask is that the battery for this model is 11volts, lower than most laptops at 15-17 volts.  The 19volt charger is ***supposed*** to autodetect  & autoadjust accordingly so it can be used for different models. So at this point, the power supply (if original) would be my prime suspect in instigating the issue again. Jack E/NJ

    Jack E/NJ

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    After the first incident I measured the output voltage of the original power supply, but could't get any sensible readings. The repair shop where I took the machine confirmed me that this was the case.

    So when I replaced the motherboard I needed also a new power supply. However I couldn't find an original Acer one, so I bought a universal Deltaco SMP-120WD power supply with replaceable connectors for different laptop brands. This power supply selects the correct output voltage based on the selected connector, so when I selected the Acer type connector, the voltage was automatically set to 19 volts.

    But you are now saying that the correct voltage for this machine is actually 11 volts? So, have I destroyed the new motherboard by running it with the Deltaco, which probably doesn't autodetect & autoadjust, but just puts out 19 volts based on the selected connector?

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    Yes, I'm sure I could have found an original charger, but the Deltaco one was readily available from a nearby shop, so I decided to grab that. As the original Liteon charger was specked at 19V/6.32A/120W, and the Deltaco is specked at 18–19V/6,66–6,31A/120W when using a dedicated Acer connector, it never even crossed my mind that it would not be compatible...
  • JackE
    JackE ACE Posts: 44,627 Trailblazer
    Options
    You might want to doublecheck with Deltaco anyway . It might be compatible with 11volts even though the ads feature 15-20volts. https://www.deltaco.eu/en/Pages/Support.aspx
    Jack E/NJ


    Jack E/NJ

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    Hi, I should really stop trying to pretend that I understand something about computers, electricity, voltages, measuring... I took the original charger out of the bottom of my drawer to check once again its specs. Out of a sudden impulse, I plugged it to the computer and pressed the power button - and the ***** machine started! I really don't understand what I have measured back when I concluded that the charger was broken. The only thing that makes me feel a little bit less ashamed now is that also the repair shop guy made the same conclusion for some reason.

    Anyway, now I'm back in the situation where the machine works ok for basic use, but freezes or gives a blue screen with heavier load.

    To answer your earlier question about driver versions, here they are:

    Intel HD Graphics 4600: 10.18.15.4248
    NVIDIA GeForce GT 750M: 22.21.13.8205

  • JackE
    JackE ACE Posts: 44,627 Trailblazer
    Options
    OK. The old adapter may have an intermittent wire break near the laptop plug or wall plug.


    The Nvidia looks like a generic Win10 driver. The only ACER drivers are for Win.8.1. But we could try to install them anyway in Win10's Win8.1 compatibility mode if bluescreening remains. Or possibly use DriverBooster or similar driver tool freeware to see if it can find anything better.

    Jack E/NJ 


    Jack E/NJ

  • juhas
    juhas Member Posts: 24

    Tinkerer

    Options
    OK, I installed the Intel graphics driver that you suggested and left the Nvidia driver as is. Then I installed the DriverBooster, which is satisfied with both drivers. It found 20 other out-of-date drivers which I let it update.
    I also updated bios to the version is 1.15 and Windows to the latest build 1903.
    None of these had any effect on the main problem, i.e. freezing or bluescreening when trying to start more demanding games.

    At this point I started to pay attention to the fan behaviour. It runs at high speed almost all the time. Sometimes it turns to high speed almost immediately after Windows has been loaded, sometimes after I open some app, but when it turns to high speed, it never returns to lower speed during the same session. But most of the time I don't see any good reason for the high speed. When I use the DriverBooster's Performance Monitor to see the system temps and CPU usage, I don't see any alarming values there. For example at the moment when I'm writing this message, the CPU temp is 38 degrees Celsius, GPU temp 37 and motherboard temp 32, and CPU usage is mostly between 0-2%, but the fan is running at 1798 rpm. And yes, before you ask, I did clean the fan thoroughly as part of the motherboard replacing procedure so there's no dust preventing the air flow.

    I did however disassemble the machine once again and replaced my earlier, possibly not so good thermal paste with Noctua NT-H1 for both CPU and GPU. After this I didn't see any change in the fan behaviour, but surprisingly the mentioned more demanding games started to work, but only if I disable the Nvidia driver and use only the Intel graphics. If I enable the Nvidia driver and use it for these games the same freezing or bluescreening occurs again. However, even just before these freezing occasions I don't see any excessive temps in the Performance Monitor.

    Can you find any clues from the above long and meandering description for what might be wrong and what I could try next?

    Thank you.