Dell Latitude 5310 2 in 1 Laptop does not power on, shorted capacitor replaced but not solved

[im_trying]

Laptop does not power on but has a fix white light on power button, when connected to power.

I found, while trying to diagnose, a hot spot in the motherboard and found it to be a shorted capacitor (see photo below) on the 2.5v (2D5V_S3 on schematics). After replacing it with one from a donor board, still, the board does not turn on...

The usb-c meter reads upon connection 20.1v and 0.00a, with some occasional flashes to 0.03amps. After 10/15 seconds circa, it goes to 5.2v and draws an almost constant 0.07amps. (same behaviour as before)
To my fingers, nothing seems hot (I don't have a thermal camera). I do however have a bench power supply, if injecting voltage can find the culprit.


Thanks in advance

[kakazu]

try to check the mostfet main power

[im_trying]

It is getting through both mosfets of dc-in, it measures 20v when the usb-c sends 20v. And 5v when it sends 5v.

The 3.3v coil and the 5v coil are both present.

All measurements are taken with the motherbard out and nothing attached.
I just noted that with the battery attached, sometimes the white led on the power button doesn't turn on, even though all the coils have the same voltages.

[kakazu]

Try to check if power IC is good if not replace it

[im_trying]

I don't know how to do that exactly... Still a newbie, but im trying. Should I check for any pin in particular on the chip? Like LDO?

[im_trying]

I checked the the LDO I found in the schematics, which there are two. A 1.8v near the PD controller, and a 1.2v on the other side of the board. The 1.8v is present, the 1.2v is not. I guess we're making progress but I don't really know how to procede. Is it a bad EC chip? A bad BIOS for the EC chip?