Acer Nitro 5 AN515-55 (LA-K862P GH51M) - Turns on for a split second, fans spin then stop, lights stay on (Not BIOS/EC)

[Jazoe]

Hi everyone,
I am working on an Acer Nitro 5 AN515-55 with motherboard model GH51M LA-K862P.
The Symptoms:
When I press the power button, the cooling fans spin up for a fraction of a second and immediately turn back off. However, the keyboard backlight remains on, the power LED stays solid blue, and the charging LED remains solid orange (indicating it detects and charges the battery normally).
There is no image on the screen, and the laptop appears stuck in an early power state.
What I have tried so far:

1. Power Drain & Hard Reset: Disconnected the main battery and CMOS battery, held down the power button for 60 seconds. Behavior did not change. Tested on adapter only (without battery) with the exact same results.
2. Crisis Recovery Mode (Fn + Esc): When triggering the crisis recovery shortcut, the fans ramp up to 100% full speed and stay spinning continuously, but the board does not attempt to read the USB drive or flash anything.
3. BIOS & EC Reprogramming: Since the Fn+Esc mode worked, I suspected a corrupt firmware issue. I pulled the dumps and received a clean Main BIOS (16MB) and EC (2MB) file from a forum member here. I successfully flashed both chips using an external programmer (NeoProgrammer). Both chips erased, wrote, and verified 100% successfully. Unfortunately, the behavior is exactly the same after the flash (fans spin for a split second, then stop; lights stay on).

Since this rules out a corrupt BIOS or EC firmware, I am dealing with a hardware fault—likely a short circuit on one of the power rails causing the Over-Current Protection (OCP) or an IC to drop the power sequence immediately after the fans get power.
Before I start injecting voltage or blindly hunting for shorted MLCCs, I wanted to ask the experts here:

• Are there any known common-failure MOSFETs, DrMOS chips, or capacitors on this specific LA-K862P board that cause this exact symptom?
• Which specific power rails or Power Good signals should I trace first with my multimeter given that the keyboard backlights and power LEDs manage to stay powered on?

I have a multimeter and am ready to measure resistances on the coils. Any guidance on where to look next would be highly appreciated!
Thanks in ahead!

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[harp]

On Sorin yt channel is a few videos about repairing acer nitro 5, so check it. Maybe to check 5v if you say that usb not working... see https://m.youtube.com/watch?v=Ruwvhcf0oLw

[Jazoe]

I saw that too, actually, but it’s not the same problem as mine.