Bricked Latitude 7530 laptop

[shamooooot]

Hello

Sadly, I accidentally shorted the 5V power pin of the USB port to around 20V power, and the laptop turned off and will not turn on anymore. I hear hissing sound in the motherboard like there's a short circuit somewhere. I tried disconnecting and reconnecting the battery but with not luck, also on the USB-C power it is the same.

I did try and traced the 5V rail and I found this IC overheating. I did remove it after a huge struggle for long but the short is still there. Also the laptop still doesn't turn on and the charger light doesn't light when plugged..

Should one expect the output caps of the IC to be bad, or could the short have reached other important chips?.

DNBxyz = Silergy SYD370CTMC
https://www.badcaps.net/filedata/fetch?id=2116761

I don't have access to thermal camera.

[mon2]

Go back to the usb port with this transient voltage. Review the resistance to ground of VBUS. All parts here are suspects. Most likely a local usb load switch and vbus linked caps will be found to be defective. Flux and remove each till the short is removed. Keep track of the parts, their location and their polarity (if applicable). Ceramic caps are not polarized but other caps may be.

[reformatt]

My previous experience with such things usually results in a shorted PCH, as the USB ports are usually connected directly to it. Check your PCH power rails first before wasting any time on it.

[shamooooot]

Thank you for the help mon2 and reformatt.

For Dell latitude 7320/7420 the board looks similar to the 7530, and I checked the 5V rail of the USB and it is going to these, one of them is SLGC55544CV USB Charging Port Power Switch and Controller.
https://www.renesas.cn/zh/document/d...44cv-datasheet

I am in regret now as I am realizing that I might have been too hasty to remove the IC I removed, because I remember that I was actually reading 5V on some of its pins. But the overheating and the hissing was from it's circuit, so probably the IC wasn't bad..

[shamooooot]

Guys

I had another round, and here's what happened:

- Fed 5.3v to the USB 5v rail and found it to drop from 5.3v to less than 4v, and the IC "SLGC55544CV" heats up. When I touch the IC voltage starts creeping higher to around 4V.
- Fed 5.3v to the input of the SLG and no output but the 5.3v drops to less than 4 as well.
- I took off the SLG and fed again the 5.3v and apparently the short on the output is gone now .
- Again after removal, fed 5.3v on the jumper PJP103/+5V_ALW, but it still show 3.9V!.
- The following chip gets hot and I can't put my finger on it for more than several seconds: ALC3281.

The source is 2A, and I don't know what to make of it, could there be still a short on the input side!.

[shamooooot]

Shouldn't the overvoltage reach the SLG chip and not components before it!.