Legion Y540 17irh motherboard issue ( need help to know how to diagnose my motherboard)

[Docus]

That side with the 0.4 is the output after the inductor, not on the RT6585 side, solder a wire on the shorted side from.your bench PSU and do the voltage injection, start with 1V 2A

Check what gets hot, hopefully not the PCH as it would mean the end, replacing a PCH requires an expensive BGA rework station

May be also the IT8226 this time, I don't know if it has to be programmed first by an external programmer (expensive), or if the motherboard can program an empty/new EC, some boards do, some don't

i forgot to ask if the voltage (0.84v) is normal or not

[m1ch43lzm]

The voltage drops, because you set the current limit to 2A, you can try increasing the current limit to 3A

As it's drawing 2 amps something should be getting warm at least
Maybe it's the "Lenovo" IT8226 iC on the other side of the board?
Another trick with alcohol:
1. Add the drop of alcohol where you suspect the short, don't connect the wire yet, just solder one end to the shorted line
2. Touch the wire to the PSU + terminal you can see that the alcohol "moves" a bit, not necessarily evaporate, that depends on ambient temperature
3. Disconnect the wire, the alcohol "moves" again
4. Repeat step 2, you'll notice where the alcohol "moves", that's the hot spot