820-00923 no power stuck in 20v 0amps

[punkieftw]

Hi, first let me excuse me about my very bad english.

I have a retina usb-c model coming from another store, had some liquid damage but i never see that cause the first place clean that. So, they replace some components randomly i pretend.

When the machine comes to my store, in the usb-c meter was got nothing. I replace the U7000 and restore the PP3V3_G3H. From here, all is going well.

In the firsts attempts of the machine to turn on, used to get 19v and 0.22 amps in the usb-c meter and does not turns on. later on a 8th attempt i realized some part was getting so hot. that was Q7030/40. i get out those from the board, i measure all the pins of the Q7030/40 looking for some short to ground, and no have any short. so, i assume this components are bad. i replace those two, and at this time only the Q7030 got hot. But no have any short, i replace that again and have the same.

Later same day, and now in the USB-C meter have 20v and 0.00 amps. I got some measures and i realized i have low PPBUS 1.6v i look for a short to ground and is not shorted. Looking for this rail i have noticed the PPDCIN_G3H is missing. so, i have PP20V_USBC_XB_VBUS but i don't know where look from now.

These types of machines are very confusing.

I suspect the liquid was in the u7000 area, Q7030, and U3100/200 Because the board looks in these areas.

Please, let me know where i must look or measure.

thanks in advance.

 

[2informaticos]

What is the USB-C meter indication now?
Do you get voltage at R7020?
Why did you change Q7030/40 without checking them?
If already removed from board why didn't measure them?
If was liquid on CD3215 chips, is better to reball them.

 

[punkieftw]

Hi, Thanks for ur fast answer.

The USB-C meter now indicate 20.0v and 0.00 Amps. (for a second, gets 19.9v and 0.003 Amps but just a sec).
In the R7020 get 0.0070v in all pins and i measure in resistance mode too, get O.L.
I change the Q7030/40 because those two was getting hot and i try to take out of the board to measure and look for a short.
I can reball that CD3215 but i dont think this have some crap in his pad cause this CD3215 have this black resin under the chip.

 

[2informaticos]

Really no voltage at R7020?
How do you get 20V on USB port then?
3V42 and proper SMC_RESET_L signal required for that; no way if U7000 doesn't work...

 

[punkieftw]

When i plug in the usb-c , gets first 5v and the U7000 generates the 3v3 to power on the CD3215.. then, switches to 20v and 3.3v disappears.

 

[punkieftw]

Hello?

Any ideas?

 

[2informaticos]

Your board remains at steady 20V, with 0V at R7020?
Post diode mode (red probe at ground) at F7000.