820-00923-a not turning on

[PPVCC_S0_CPU]

Have minor liquid damage around cd3215 chip cleaned it and tried to turn it on but nothing happening, board does goes to s0 state as l7210 is outputting voltage, one thing i noticed that whenever i plug usb c charger in, mosfet near cd3215 gets extremely hot for a brief second and then it cools down, those mosfets does pass 20 volts from them, so there is no short on that line. Cpu also gets warm, i have already put new clean me bios on it but it does the same thing, no light comes on usb mouse.

 

[SMMRepair]

Make sure you used a C00 CD3215 and not B03; check chip face. Made the same error a few times (the B03's are easier to pull from the 00840/75 boards), but the 00923/239/etc need C00.

 

[2informaticos]

Liquid spill on these boards is big danger for CPU.
All USB-C ports work?
Did you test USB mouse on different ports?

 

[PPVCC_S0_CPU]

Make sure you used a C00 CD3215 and not B03.

i didn't replaced those chips


Yes all port are working, one thing i noticed that on working board pin 5,6 of u6100 don't have any voltage and rest of pins have 3.3v, but on this one pin 5,6 have .9 and .7 v and rest of pins have 2.4v.
can it be a bios issue?

 

[2informaticos]

"rest of pins have 2.4v"
Don't you have 3.3V at pin8???
Check 3V3_SUS voltage.

 

[PPVCC_S0_CPU]

Yes i have 3.3 on pin 8, sorry my bad

 

[JohnB8812]

Sounds like CPU got killed to me. That fet getting hot btw I think is normal as I?ve noticed the same thing on some of the ones I?ve fixed...really weird. Was there any liquid near the CPU or the LCD connector?

 

[PPVCC_S0_CPU]

Yeah there was bit of a liquid on lcd connector

 

[JohnB8812]

Yeah so what happened was likely that the 40 volt backlight pin shorted to the 1 volt CPU pin next to it and sent 40 volts to the CPU. On the 13" Models, it's RIP every time.

 

[PPVCC_S0_CPU]

I think its a bios issue as pin 1 have 1.4 instead of 3.3volts, i have u6101 and u6100(with clean me) but it still gets 1.5v.
when i remove u6100, it will have 3.3v

 

[2informaticos]

BIOS data pins (2, 5, 6) will never stay high, on working board.
Commonly 0V there, when checked with DMM.
An o-scope, or LED trick, can show you if there exists communication.
The pull-up resistors are in PCH normally.
If data lines stay at 3.3V means PCH doesn't access/read BIOS.