820-02100 Power off after water damage

[jxx]

Hello, this board has water damage.
It goes up to 20V, then turns off and on again. I keep repeating. It boots normally when turned on with the battery but won't charge.
There was water damage in the UG400 (CD3217), and I replaced the UG400 and peripheral capacitors. The symptoms are still the same.
There is no particular short value when testing the diode.
There is no PP0V9_ATCRTMR2_LVR voltage value. (There is no diode test short.)
There is no PP3V3_ATCRTMR2_SVR voltage value. (There is no diode test short.)
There is no PP3V3_S2SW_USBC2 voltage value. (There is no diode test short.)
CG400 of PP3V3_S2 circuit was corroded and replaced, and now it is 3V3.

 

[2informaticos]

If machine works with battery, there your problem is located in the USB-C area.

"I replaced the UG400"
Where did you get it from?
MUST come from same donor board, maintaining its position in boardview.

 

[jxx]

이 기기가 배터리로 작동한다면, 문제는 USB-C 영역에 있습니다.

"UG400을 교체했습니다"
어디서 알아냈어?
MUST는 같은 기부자 이사회에서 나왔으며, 이사회에서 그 위치를 유지했습니다.

Thanks to reply
I get it from same donor board and same location.
Even before replacing the Ug400
It was same problem.

 

[2informaticos]

All USB ports have the same behavior?
Check with Magsafe 3 charger also.

Compare diode mode readings around all CD3217 chips; start with their LDOs.

 

[jxx]

All USB ports have the same behavior?
Check with Magsafe 3 charger also.

Compare diode mode readings around all CD3217 chips; start with their LDOs.

Yes, all ports have the same symptoms.
MagSafe 3 works fine also charges well.
Around CD3217 diode value looks fine except above values.

 

[2informaticos]

That's really strange, because magsafe 3 port is also based on CD3217.

Compare diode mode to ground readings around UG000 and UF100.
Also between UG015 and UF115.

BTW, any reason to quote an entire post visible few centimeters above?
Write directly into bottom reply box, instead of clicking Reply button.
Please, maintain forum aesthetic.

 

[jxx]

I don't know why, but the symptoms suddenly disappeared and everything is working fine now. Anyway, the problem was CD3217.