Where to start checking the laptop motherboard?

Question

Do it yourself

And so, DNS client 123308.
History: I stood with a faulty hard drive as a stand for a cactus (yes, that's right)
While watering my favorite cactus, water over the glass cover inside.
Clinic: Does not respond to button presses
When the power supply is turned on, the charging indicator lights up briefly and goes out.
When disassembling, there are traces of liquid in the lower part, which the client himself eliminated, there are no visible damages.
When the 3.4V contacts close next to the cable from the power buttons, it is possible to light the power indicator, while the processor heats up (after a few seconds it is impossible to hold your finger), the cooler does not work.
The power supply is OK.
When you connect the power supply to the motherboard, there is a click and a subsequent quiet background in it, I couldn’t determine it more precisely, the processor was filming.
upd
Field of half an hour of "listening" to crackles, and incidental software repair of Hdd, cleaned everything again with alcohol and collected it.
Now the clinic is like this, probably the battery has dipped and is not charging, so as soon as you plug in the power supply, the power and charge indicator lights up, and the multimedia keys are highlighted, then everything goes out, after a few seconds the power and caps lock indicators light up and get hung up on themselves until you pull out the block.

Answer 1

Sounds like a fatal accident. Look for fuses on the board and see if they work. Look for other elements that get very hot (where breakdown may occur). If the client climbed himself, he could short-circuit and kill something else.

Answer 2

Looks like a short circuit.
There is an artisanal method for detecting a dead element.
It is described in detail in this video .