Asus UX435EG no power - what to test?

[nivminkov]

Hey guys,
Happy to find this awsome forum.
I'm trying to repair a laptop I bought (wasn't mine). I have some experience and equipment but i'm new to laptop repair so I don't know what to test.
There is a picture of the board here (another post)
This is the testing Iv'e done:

• When i'm connectng TYPE C I get 19.2V on a capacitor in the middle of the board
• 8.39V on a buck that get's the 19.2V input, apperantly this is the main system voltage since I get it in the input of every buck and on the current sense resistor.
• 3.36V on another buck
• 5.22V on another buck
• Other bucks don't have any output at all
• Tried to find shorts on the board (on capacitors), couldn't find. Only the GPU buck output cap is 0.3ohm to ground. Tried injecting 0.8V to the board at this point resulted 0.63A so I don't this is the problem.
• CPU is getting hot in this situation (no fan spin)
• NO leds/screen, even after power button

What to test next?
Thanks for the help and tips, much appreciated

[nivminkov]

Adding some more test since I cannot find edit button

• This board uses 2 type C connectors for charge (both have lighting symbol on them)

• Upper port shows 19V 0.52A with TYPE C tester (added pic)

• The second port shows 0V 0A (added pic), and I can see someone has been adding one Bodge wire to the connector and one of components on the board (resistor)

I cannot see any more repair attempts on this board, but I cannot assure you there are not any.
Thanks

[nivminkov]

OK so I made some more testing, found a SPI flash IC that gets really warm, not looking natural to me. P/N is winbond W25Q128JVPIQ, packge is WSON8. It is located near the EC chip (IT5125VG-128). Not sure if it's the bios memory. There are some more SPI flash ICs on this board but they don't get warm. Datasheet says it should consume only 20mA. Measuring voltage on pin8 (VCC) is 3.07V. I think he's stressing some LDO output. I ordered a programmer, WSON8 socket and the IC itself from AliExpress. In case I won't able to read the contents of the flash, where can I find an image for it?
Attached an image (EC from the left side)
Thanks

[mon2]

Hi. Remove all power. Meter in resistance mode. Measure the resistance to ground of pin # 8 on this flash IC. We are checking if there is a higher than normal resistance to ground on this power rail. Perhaps the heat is from some nearby part and not this flash IC?

If the flash contents are required, that request will have to be made inside the dedicated bios forum. See above. Someone there should be able to assist to get you a dump for the EC firmware flash IC.

BTW - the flash IC should also be available from mainstream distribution channels like Digikey / Mouser / Arrow. Winbond is very popular but of course Aliexpress is convenient. China has everything.