Acer 6920G with strange error - sometimes boots and sometimes not, and rare fan noise

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  • CasasElectronics
    Member
    • Mar 2019
    • 33
    • Spain
    #1

    Acer 6920G with strange error - sometimes boots and sometimes not, and rare fan noise

    Hi, I've been troubleshooting this PC for a while but I cannot repair it for now.

    The error on this PC was the known graphics card soldering problem (or that was what I was thinking), so I took a 3470 from a 5920G and installed it.

    The video after that worked, so I thought the problem was solved. When I tried to install windows, I noticed a problem: the ACER logo (bios load) stopped after completing the loading bar (and that was in every power on, but sometimes not even charged the Acer logo screen, I only could see a blinking white bar).
    So I thought it may be some problem with bios, but found in another thread It could be NEC TOKIN capacitor. I extracted it and mounted some capacitors from other boards (attached photo), but problem continued exactly the same.
    Click image for larger version Name: IMG_20250225_221943.jpg Views: 0 Size: 3.57 MB ID: 3581218
    Thinking again in a BIOS problem, I reprogrammed the bios, but the same effect appeared.

    Testing voltages I can find in board correctly: VCORE(0.95-1.1V), 5V(5.3V on usb), 1.5V, 1.8V, 1V, 19V, and nothing fluctuates when fail appears.

    Another problems noticed are:
    - when Windows starts (sometimes it does it), after a time it freezes. Last time I tried Windows 10 and got an BSOD with error "DPC WATCHDOG VIOLATION".
    - sometimes I hear a fan noise like clicking, and fan tries to rotate but cannot. Sometimes at power on if this happens, laptop does not start. When not happening. it starts normally.

    I also have noticed that I can start windows normally if I let the computer a certain time powered off. When is a short time after power on and power on the problem appears.

    Any idea about this?


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