HP Pavilion G4 (DA0R13MB6E0) Doesn't power on, MAINON oscillating

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  • BrennoMaturino1
    New Member
    • Feb 2024
    • 4
    • Brazil

    #1

    HP Pavilion G4 (DA0R13MB6E0) Doesn't power on, MAINON oscillating

    I got this motherboard from HP that wouldn't turn on, after testing it, turns out that the more accurate description would be that the power LED is flickering and it won't display anything, i got some backstory from this board, it wouldn't output video and another technician tried to reseat the LVDS cable with the laptop on hoping it would work, all it did was fry both the display and motherboard, magic smoke was released from the screen and cable, i thought the PCH was probably killed and went full shorted, i tested the PWM and it outputs a power good signal and no fault, but it quickly falls, but for some reason i checked the enable, i could see it oscillating (a quick pulse repeating every ~1 seconds), this power enable signal comes from the SIO in a trace called "MAINON" that tells almost all power chips (and power led i guess) to enable, , i'm starting to think either the SIO or PCH were damaged, is there something else i could check in this board? I also checked all the other coils, i'm pretty sure there is no short in this board
  • Answer selected by BrennoMaturino1 at 12-03-2024, 10:35 AM.
    Sametbey
    Badcaps Veteran
    • Jan 2021
    • 229
    • Turkey

    If you removed and reconnected the LVDS socket while the adapter was plugged in, the PCH is faulty. Good evening,

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    • mcplslg123
      Badcaps Legend
      • Jun 2015
      • 7262
      • india

      #2
      What is the resistance to GND on "Mainon" pin of SIO?

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      • BrennoMaturino1
        New Member
        • Feb 2024
        • 4
        • Brazil

        #3
        Originally posted by mcplslg123
        What is the resistance to GND on "Mainon" pin of SIO?
        80K, there is no short on this line too, i already expected this since the voltage wouldn't even rise in case it was shorted, signal lines are really high impedance, earlier i tried making a jumper from MAINON to +3VS5 since i noticed this line comes on when i press the power button and maintains itself, i got a higher current draw i believe is from the PCH VRM, but it didn't enable VCORE, and the power led kept blinking, the power LED is powered by a separate GPIO on the SIO (PWR_LED#), there is still a possibility of the SIO/PCH being damaged (i don't know which one is more likely to die by shorting a bunch of LVDS and power pins together) and some internal damage causes them to reset during startup sequence and get stuck

        Comment

        • Sametbey
          Badcaps Veteran
          • Jan 2021
          • 229
          • Turkey

          #4
          If you removed and reconnected the LVDS socket while the adapter was plugged in, the PCH is faulty. Good evening,
          I'm not happy to be so strong. because it's not humanly

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          • BrennoMaturino1
            New Member
            • Feb 2024
            • 4
            • Brazil

            #5
            Originally posted by Sametbey
            If you removed and reconnected the LVDS socket while the adapter was plugged in, the PCH is faulty. Good evening,
            It was not me, as I said it was another technician that did it and told me since i do board repair, i was already expecting a response like this, thank you

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