ACER PEW71 LA-5894P CPU_B+ MOSFET NEED HEPL

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  • jermac0711
    Senior Member
    • Jun 2022
    • 55
    • Philippines

    #1

    ACER PEW71 LA-5894P CPU_B+ MOSFET NEED HEPL

    Brand : Acer
    MOBO: PEW71 LA-5894P
    Issue: initially no power. PQ73 mosfet is busted. (AO4466) . Unit has power now but PQ87 is heating up too much (observerd under thermal camera) causing to shut down the system. I tried to remove the removable CPU and the mosfet temperature went normal. I have a replacement CPU from same model but everytime there's a CPU, mosfet PQ87 temperature is rising rapidly.
    I hope you guys can shed some light. Thank you so much in advance.
  • mon2
    Badcaps Legend
    • Dec 2019
    • 13830
    • Canada

    #2
    Each of these mosfets in this cluster is a suspect. Generally, each of these mosfets should be replaced if one is found to be defective else risk killing of the CPU. The high side mosfets are very dangerous since they pass a much higher voltage down to the CPU voltage but if they leak, then the CPU is toast.

    Remove all power. Meter in resistance mode. Measure the resistance across each of these mosfets.

    source / drain
    source / gate
    gate / drain


    Post each measurement. Each measurement must be hundreds of k ohms or higher else it may be defective. Test each of these mosfets.

    Comment

    • mcplslg123
      Badcaps Legend
      • Jun 2015
      • 7262
      • india

      #3
      You need to replace ADP3212 along with all mosfets connected to it plus the CPU to make it work.

      Comment

      • jermac0711
        Senior Member
        • Jun 2022
        • 55
        • Philippines

        #4
        Originally posted by mcplslg123
        You need to replace ADP3212 along with all mosfets connected to it plus the CPU to make it work.
        Yup that is what I suspected as well since I already replaced all 4 mosfets but still the same. ADP3212 is the one who controls the gate of these mosfets. Thank you for solidifying this. I'll be waiting for the ic to arrived. I will keep you guys posted for future reference.

        Comment

        • jermac0711
          Senior Member
          • Jun 2022
          • 55
          • Philippines

          #5
          Originally posted by mon2
          Each of these mosfets in this cluster is a suspect. Generally, each of these mosfets should be replaced if one is found to be defective else risk killing of the CPU. The high side mosfets are very dangerous since they pass a much higher voltage down to the CPU voltage but if they leak, then the CPU is toast.

          Remove all power. Meter in resistance mode. Measure the resistance across each of these mosfets.

          source / drain
          source / gate
          gate / drain


          Post each measurement. Each measurement must be hundreds of k ohms or higher else it may be defective. Test each of these mosfets.
          I did replace the mosfets already but still heating up. Luckily I have replacement CPU as well. I will be just waiting for the mosfet controller ic to arrived.

          Comment

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