acer nitro 5 not powering on. GH53Z LA-L031P

[pozarek89]

Hi
ACER NITRO 5, Ryzen platform
MB GH53Z LA-L031P
Background: Client was changing thermal paste and he didn't unplug the battery.

When pressing power button, laptop indicates blue diode and after 4seconds it is shutting down. Same behavior on battery and AC adapter.
I didn't find any shorts. What I found is missing BIOS supply (I'm not sure if this Voltage is always on), 3.3V on SuperIO chip is present (also on SM BUS).
What bothers me is very low resistance on GPU (equal to multimeter wire resistance). I got stuck. I don't have BV or Schematic.
Any suggenstions ;/?

Thanks in advance.

[mon2]

Re: acer nitro 5 not powering on. GH53Z LA-L031P

GPU is with a low resistance, naturally.

Review the dcin mosfets that follow the DCin connector.

Measure the voltage to ground of each pin, each mosfet.

Post your measurements (err..for the logic board).

[pozarek89]

Re: acer nitro 5 not powering on. GH53Z LA-L031P

Resistance 0.5 Ohms where this is basically resistance of Multimeter wires is correct?

Another question is about BIOS for Ryzen. I heard you don't have to bother about ME Region because this is not Intel platform, however I never touched BIOS binary and I don't know which parts of BIOS firmware I should move to new binary (DMI, Windows Key etc.) Does anyone have guide or instruction?

[mon2]

Re: acer nitro 5 not powering on. GH53Z LA-L031P

Yes, Nvidia GPU will be less than 1 ohms.

The GPU is usually not active till later in the boot and/or required to accelerate the graphics. The bios screen for example will not use the GPU. That is my understanding.

[pozarek89]

Re: acer nitro 5 not powering on. GH53Z LA-L031P

Alright. I have schatic now so I can measure some stuff.
3V and 5V LDO are prsent. ACIN and EC_ON signals have both 3.3V. after hitting power button 1.8V shows up on BIOS chip and 3.3V from switching supply is also present.
After 4 seconds eveyrthing goes back to previous state.
I will probably have to reflash BIOS. KBC seems to be working fine.
Any Ideas?

[piernov]

Re: acer nitro 5 not powering on. GH53Z LA-L031P

The GPU is usually not active till later in the boot and/or required to accelerate the graphics. The bios screen for example will not use the GPU. That is my understanding.

It depends on the platform. Some of them boot from dGPU, some of them boot from iGPU, some of them boot from one and switch to other other at a later point, or some exclusively run on dGPU (or iGPU if there is no dGPU present of course).
I can't tell you how to easily know which situation it is though.