Asus Zenbook "braindead"

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  • AppleLover123
    Mr.Bombastic
    • Dec 2023
    • 61
    • Germany

    #1

    Asus Zenbook "braindead"

    Hello guys,

    i have an Asus UX51VZ here from scratch.
    It powers on and won't post. (fans not spinning)
    The first thing i noticed is that the ampage that it takes is the same everytime.
    Like it won't change if i reset the bios with the battery. It stays at the 470 milliamps when turned on.

    I found that all voltages are okay except on the vcore and gfx_core.
    On Vcore 0 Volt as well at GFX_Core just 1 volt at nvdd.

    Vcore = 1.4 ohms
    Nvdd= 23 ohms
    Gfx_core= 1.4 ohms

    Now in my opinion i think that the cpu is partial shorted and nothing more.
    But the interesting thing is that it wasn't caused by a mosfet or else because i saw no marks on the mobo that someone worked there and
    the warranty stickers on the case and the heatsink were there as well.

    So how the CPU got shorted and the laptop is still turning on, maybe internal?
    Or are these 1.4 ohms even normal?

    Does someone know what this cpu takes on vcore exactly when working?


    Edit:
    Before someone asks:

    Yes i reprogrammed the bios ic.
    Yes i tried other ram.
    It wont post even when the heatsink is on or over hdmi.
  • AppleLover123
    Mr.Bombastic
    • Dec 2023
    • 61
    • Germany

    #2
    I think i found the fault.

    When the Board is powered i recognize that the pwm buck Controller for the 3v5v is very hot ike it is not used to be.

    But this is not all! I found out that when you slightly press the Chip down the Laptop shuts down and is taking 840 milliamps which are going to the Ec Chip and the pwm Controller. The Controller takes the most current bc it's like a 60-70 degrees hot.
    When i desoldered the Chip i did measure a short on both 3v_lx and 5v_lx.


    Since i now have a thermal camera (which makes my life a 100 times easyer) i did find
    a shorted mosfet on both rails. (pq8000)
    Now when i power on the Laptop it takes only the 480 milliamps that it did before but now i have the 5v and the 3v (kinda) bc the coil Puts out 4.1v instead of 3v.
    Still no picture but I take a guess and say it's the pwm which is partially shorted or is that all because the cpu is taking too much current from the 3v?

    The CPU seems fine when i inject Voltage at vcore (it's heating up uniform not like theres a short)
    However when i power up the Laptop it is looking strange.
    I put thermal images down in the Attachements...
    Attached Files

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