Asus X540UV vccore short

[Cuboy]

Hello everyone,

I have got a Asus X540UV rev 2.0, this was sold to me a couple years ago and it came not working. I left it on the shelve until today.

When i plug the charger and light it on, the laptop tries to power, I see a couple of leds and then goes off. The screen doesn't power on, the hard disk spins.

I have been trying to diagnose it, and I have noticed that the vcore rail is shorted to ground, all capacitors from the rail have a low resistance to ground, I've got a 10 ohm resistance from the vcore side to ground, These are PC8125, PC8134... from the top side of the board.

Given this, how do you check if it's not the cpu that is shorted or that's something else?

I guess i could remove the whole board and check if something else gets hot, i was wondering, if it is the cpu that it's shorted, will it get hot?

Thanks.

Boardview can be found at: https://www.badcaps.net/forum/troubl...ardview-please

[Stevedb]

10 ohms on vcore is normal. Best what you can do is hd picture front and back with all resistance to ground of every coil and current sensor and which voltage are present on the coils when you have no voltage use power button and press again. Good luck then we can help

[Cuboy]

10 ohms on vcore is normal. Best what you can do is hd picture front and back with all resistance to ground of every coil and current sensor and which voltage are present on the coils when you have no voltage use power button and press again. Good luck then we can help

Oh okay, I didn't know that vcore had such a low resistance.
Okay, will try.

[Cuboy]

10 ohms on vcore is normal. Best what you can do is hd picture front and back with all resistance to ground of every coil and current sensor and which voltage are present on the coils when you have no voltage use power button and press again. Good luck then we can help

Hello I have already measured resistances to ground, going to measure voltages. So far, it seems that the current sensing resistance has 19V on it (this explains why the laptop tries to boot).

I think the top has no current sensing resistors and coils, correct me if i am wrong.

[Cuboy]

Here is voltage, i have followed the piernov guide on diagnosing the laptop power supply, but seems that the power supply works correctly since i always get the 19v from the current sensing resistance.

The measurements of the voltage are taken when the led indicates that it's going to power on (the white led goes on, and after a bit off), there's an orange led that indicates that the charger is plugged in but when measuring voltage in that state, almost everything is around 0V but the dc in circuitery.

When plugging the charger, the orange light goes on, it stays on (sometimes doesn't and i have to press the power button), when i press the power button both the orange and white light go on, finally the white light goes off and the orange stays on.

This is the correct boarview, not the one i posted below https://www.badcaps.net/forum/troubl...40uv-boardview

[Cuboy]

Here are the voltages remeasured again, from the lower load side.

[Cuboy]

Flashed the bios with a good known bios, same result.

[Cuboy]

Someone on discord help me read the contents of the bios after i tried to boot it, it seems that it doesn't get to the Management Engine inside the PCH.