XPS 9520 not powering up. Solid orange led

[Weelcup]

Hi friends

I have a dell XPS 9530 which had some liquid damage to the usb area. I replaced both the usbc iCs and not I can see 20v on the meter. But it does nothing and the 20v is not passing to charge the battery or turning on the board either.

I suspected the PD controller (usbc controller) but it will need to be flashed if I decide to replace it. I thought that if the usbc controller needs flashing then at least the board should turn on on the battery. I charged the battery externally and attached it to the laptop. Now the 11.8v is actually passed to the board I can measure it every where it should be present and it does. But the laptop is still not turning on. Now when I press the power button, it does blink orange led but it keeps solid orange during holding the power button, once I release the power button it goes. So it is technically not blinking but only lighting up while I keep holding the power button!


I have never come across similar issues, although I saw this post on Reddit for someone who had exactly similar symptoms but ended up replacing the board.
https://www.reddit.com/r/DellXPS/s/CKN6Qj6VA6

Any suggestions?

[reformatt]

Start with motherboard part number and links to schematic/boardview if available. Laptops with USB-C charging usually have boost/buck power supplies so it should still provide your main power rail (roughly the voltage of the battery) with only 5V. When USB-C is 5V, it's in boost mode, when it's 20V it's in buck mode.

If you aren't getting your main rail with 5V from USB-C, that's where you start. 20V often only gets negotiated when other ancillary power rails appear and you need the main power supply at least to be working for those to be generated.