HELP. Burnt component on GT72 motherboard

Discussion in 'MSI' started by johnbb, Nov 23, 2018.

  1. johnbb

    johnbb Notebook Consultant

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    Hi everyone,
    I need your help! A MSI GT72 motherboard I got has a burnt MOSFET (Q24) next to the MXM slot and the RAM slot.
    I was able to pull a large picture from the internet but it's not clear enough for me to read the inscription on the MOSFET itself.
    Could you help me out?
    Thanks fellas.
     

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  2. Falkentyne

    Falkentyne Notebook Prophet

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    Pinging @Khenglish
    Any chance you can mail him the board? He can fix it for you but please reimburse him for his hard work. He's probably the only person here besides brother @Prema who is capable of this.
     
  3. Khenglish

    Khenglish Notebook Deity

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    Judging from the location it will be a power switch for the 19V rail to the MXM slot. It will be a p-channel FET. The other side of the board should have the same transistor in parallel that you can read a part number off of, or you can just buy any 5x6 mm pFET. Look for something under 30 mOhm, the lower the better.
     
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  4. johnbb

    johnbb Notebook Consultant

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    Thanks mates!
    I'll try to see if there is the same transistor on the other side of the board.
    Do you think I can replace it with any 5x6 pFET? I can most probably find that on a cannibalized old Packard Bell LJ65 motherboard.
     
  5. senso

    senso Notebook Evangelist

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    Spend 3-4$/€ and buy a decent know good part from Mouser/Digikey, worst case, from eBay, thats an old laptop, its MOSFETs wont be all that good.
     
  6. johnbb

    johnbb Notebook Consultant

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    Hi, on the other side, there's a APL5930 VR730 SOP8 chip. Is that what you were talking about? It's labeled PU10 on the mobo. Burnt component is labelled Q10.
    I also found a Q3 labelled (8 pin MOSFET) somewhere else on the other side of the board: AO4413 BA5H1T is the reference. Could it be that one instead?
    Thanks again for taking time to answer me.
     
  7. Khenglish

    Khenglish Notebook Deity

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    Q3 looks right. Is the burned component labeled Q2 or Q4?
     
  8. johnbb

    johnbb Notebook Consultant

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    Burnt component is Q10 actually, the one next to the MXM port
     
  9. Khenglish

    Khenglish Notebook Deity

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    Hmm, usually FETs in parallel are one digit away in numbering. That AO4413 is still the right type of FET though. You can put in that or anything that matches the following criteria:

    p channel
    Vds max of -30V
    5x6mm form factor
    Rds on < 15 mOhm. Lower is better.

    Mouser and Digikey are good places to find FETs.

    Does the system work anyway despite the blown FET? It's almost always supposed to be on anyway, so if it's melted and shorted it might not really matter.
     
  10. Kevin@GenTechPC

    Kevin@GenTechPC Company Representative

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    It may be unstable somewhere along the line if the circuit is damaged. Also, a motherboard has multiple layers so what if the circuit in the under layer is also damaged from the burn?
     
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