I would start by measuring resistance to ground on all the power rails. You can do this by measuring each of the coils around the PMIC on the back, and also the large 2R2 on on the front.
sure, thank you ill update you when i come back home and test the 2R2
i have to say this, idk if there is something wrong with my usb port, at the fuse, im getting only 5,25V
Well, depends on the charger that’s connected. Assuming you are using the nintendo charger, it would output 15v with a happy switch, but we already know its not happy so I dont think 5v is too surprising. It basically means that the M92 hasn’t requested the full 15v, which could be an issue with the M92, or it could be a it detecting errors elsewhere so not doing it. I would check for shorts on all 5 power rail points before plugging it in any more.
im sorry to ask you this but im a noob on switch repairs, can you tell me where i shoud test the rails? as soon as i come home i will post the results here.
Check out this post:
Hi, i have the values of the power rails.
Purple : .345
Yellow : .025
Blue: OL
Red : .386
surely there is something funny with the 2r2 on the front of the board. it seems like corrosion on both pads but i cannot confirm that, it is white.
Those are diode mode readings could you get the resistance readings?
PURP:730 OHM
YELLOW:14.6 OHM
BLUE:5.32 MEGA OHM
RED:10.4KOHM
These are the resistance readings
Ok cool. Red and Blue look good. Yellow seems a little low though. What’s the resistance to ground on the R2R coil?
After i posted the picture above, which seems like corrosion, the 2R2 coil is shorted. i think, that’s it. (Resistance is 0.00ohm and it is shorted to gnd (beeps))
Ok, so we have a short on the SYS rail. Last time I had one of these I injected voltage and looked to see what got hot. If you have a microscope, it may be worth going around the board looking for damage / cracks on some of the tiny chips. On mine it turned out to be the small chip just below the SOC on the front of the board, and there was visible damage once I looked at it. I am secretly hoping @Severence will join in here to remind me what else lives on the Sys rail. 
i do not have the tools to inject the voltage on the rails. but i will see if any other chip is phisically damaged
It may be worth following this thread:
It shows a number of the common culprits.
Hey,
SYS rail shorts are typically due to a failed BQ IC but it’s not exclusive. I would just double check you are measuring resistance releative to ground and not directly across the coil though and if so after let me know specifically what the resistance readout is, then you can go over the points Calvin highlighted in that post at the other areas of the board that this rail shows up and see which area represents the lowest reading which will give you a better idea as to where the culprit lays (BQ IC for example) after you can remove the suspect and see if the short clears.
Hope that helps 
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Hi severance, thank you for coming in and help. The reading of the rail that i gave (which are PURP:730 OHM
YELLOW:14.6 OHM
BLUE:5.32 MEGA OHM
RED:10.4KOHM)
is from the ground and not from the coil.
i do not have any dc injector tool, should i see only the resistance?
I’m doing that, the lowest resistance point, should me give very low resistance, i will tell here where the lowest spot resides.
The one wich is horizontal is giving me 0.00ohms
This one, next to the BQ ic is OL