HELP! MSI GT72 power issues

Discussion in 'MSI' started by Yan92, Oct 9, 2020.

  1. Yan92

    Yan92 Notebook Enthusiast

    Reputations:
    0
    Messages:
    46
    Likes Received:
    5
    Trophy Points:
    16
    Thanks Senso, looks like RS have it. Just to check, is this the right part?
     
  2. senso

    senso Notebook Deity

    Reputations:
    548
    Messages:
    1,627
    Likes Received:
    756
    Trophy Points:
    131
    I looks like it is.
     
  3. Yan92

    Yan92 Notebook Enthusiast

    Reputations:
    0
    Messages:
    46
    Likes Received:
    5
    Trophy Points:
    16
    The MOSFETs have arrived, just waiting on the hot air station now.

    Does anyone have any advice on removing/installing MOSFETs? I've not done this before, so would appreciate instructions.
     
  4. senso

    senso Notebook Deity

    Reputations:
    548
    Messages:
    1,627
    Likes Received:
    756
    Trophy Points:
    131
    Flux, lots of flux.
    Pre-heat the pcb at around 120ºC for 3-4 minutes and then put the hot air at around 380ºC and circle on MOSFET at a time, and use fine point tweezers to remove the MOSFET, take note of the rotation, add more flux and put the new mosfet, circle around for 20 seconds a bit further away so the new MOSFET heats up and then solder tension will put it in place, just make sure you dont rotate it 180º.
     
    Yan92 likes this.
  5. Yan92

    Yan92 Notebook Enthusiast

    Reputations:
    0
    Messages:
    46
    Likes Received:
    5
    Trophy Points:
    16
    Thanks @senso. So there's no need to use a soldering iron at all? I can use the hot air gun to add the new MOSFET, as well as remove the old?

    Is there also no need to add/remove solder either?

    How can I check whether the MOSFET was correctly installed once complete? I'm assuming I should be checking with a multimeter before putting the card back in.
     
  6. senso

    senso Notebook Deity

    Reputations:
    548
    Messages:
    1,627
    Likes Received:
    756
    Trophy Points:
    131
    Maybe just a tiny bit of solder, that chip has a big solder pad under it, so you can't really solder it with just a soldering iron.

    To check, the pads need to be all aligned with the component footprint, and the chip needs to be correctly oriented.
    Watch this video:


    But your chip will not come off that easy, due to much higher thermal pass of the power planes on the gpu pcb.
     
  7. Yan92

    Yan92 Notebook Enthusiast

    Reputations:
    0
    Messages:
    46
    Likes Received:
    5
    Trophy Points:
    16
    That all makes sense and the video is very helpful, thanks!

    Don't I need to worry about the solder touching the wrong pins and creating a short? Or exposing the new part to too much heat?
     
  8. Yan92

    Yan92 Notebook Enthusiast

    Reputations:
    0
    Messages:
    46
    Likes Received:
    5
    Trophy Points:
    16
    I've just attempted to replace the existing two MOSFETs and add an additional two to the empty pads on the same phases.

    Unfortunately the first one was quite difficult and I ended up blackening the PCB with the hot air gun. The other 3 were relatively easy.

    Does a blackened PCB matter?

    I've also gotten some solder on a neighbouring copper pad, which I'm struggling to remove. It doesn't look like it's creating any bridges. Does this matter?

    Pictures here and here.

    Are there any tests I should do before installing the GPU? I've tested the resistance between the two large pins on the bottom right of the card and there's 58.5k ohms resistance. This is less than before I started but, as I understand it, doesn't show a short.
     
    Last edited: Oct 23, 2020
  9. Yan92

    Yan92 Notebook Enthusiast

    Reputations:
    0
    Messages:
    46
    Likes Received:
    5
    Trophy Points:
    16
    Update: Since replacing the MOSFETs on the GPU (and adding two additional ones), I've been gaming for a week or so now with no crashes!

    Apparently its rare for the GPU to work at all if its the MOSFETs are causing the problem. However, the MOSFET replacement seems to have fixed my intermittent problem!

    A big thanks to everyone that helped out! In particular @hacktrix2006 @Khenglish @johnbb @senso
     
    Khenglish, Papusan and hacktrix2006 like this.
  10. hacktrix2006

    hacktrix2006 Hold My Vodka, I going to kill my GPU

    Reputations:
    513
    Messages:
    1,658
    Likes Received:
    983
    Trophy Points:
    131
    Glad it's up and running bud.

    Sent from my SNE-LX1 using Tapatalk
     
Loading...

Share This Page