820-00875 PPBUS_G3H boosting after liquid damage

[nik1981]

Ive got a constant 5.2v on dc in now also

 

[nik1981]

No different after the SMC reflow

 

[nik1981]

I always take photos of the board before starting anything like UC.. would they help at all?

 

[2informaticos]

That's good to see where to investigate, after board is clean.

 

[nik1981]

[No message]

 

[nik1981]

After the board went through the UC, it actually looked great. Obviously something is bad but all the liquid damage appears to be at the DC end of the board

 

[nik1981]

When the battery is connected, I get 12.6v on PPBUS_G3H.. 0v when only on the charger though

 

[2informaticos]

Puff, liquid spill close to backlight output; that's big danger for the new boards
Supposedly problem with USB-C controllers...

 

[JohnB8812]

Yeah that's quite a bit of liquid damage. Do you get 5 volts on DC in for both ports currently? How do the chargeports look currently badly burned or OK?

 

[nik1981]

I get 5.2v on both ports. The charge ports look perfect, all the fuzzy coating came off in the UC and no pins etc are burnt or tarnished.

Any ideas?

 

[JohnB8812]

Ok is PP3v3_G3H present, slightly low, or missing? Being there was liquid near the CD3215s I would not surprised if they are an issue.

 

[nik1981]

PP3v3_G3H isn't present on charger (expected) or on battery. Both show 0.0v

Its near on impossible for me to test around U6990 on battery but on the charger I get 5.2v on D6905 pin 2 5.1v on pin 3
On D6990, I get 5.1v on pin 2 but 0.0v on pin 10 enable.

 

[2informaticos]

PP3V3_G3H enable comes from U7000.
As SMC requires this voltage, problem should be on U7000 area, not on USB-C controllers, nor SMC.
Cannot have communication between them, without PP3V3_G3H.

 

[nik1981]

Pin 27 on U7000 is a direct connection to Pin 2 of R6991 from what I can tell.
As I'm not getting anything on R6991 I wanted to look at U7000 to see if it is even getting the voltages it needs, but I'm not good enough at understanding the schematic just yet.

Could someone better than me let me know what voltages I need around U7000 to feed U7000 please. That way I can see if it needs replacing or its something feeding it thats is the issue.

 

[2informaticos]

Check basic voltages on U7000; P_IN, AUX_DET, VDDA/P, AUX_OK.

 

[nik1981]

Thank you 2informaticos..

Pin 10 - P_IN = 5.16v
Pin 18 - AUX_DET = 1.28v
Pin 2 - VDDA = 1.39v
Pin 17 - VDDP = 1.39v
Pin 28 - SMC_AUX_OK = 0.0v

 

[2informaticos]

Pin 2 - VDDA = 1.39v
Pin 17 - VDDP = 1.39v
Change U7000...

 

[nik1981]

Okay.. I'll give that a go.

 

[nik1981]

What should VDDA and VDDP be showing as? I'm assuming SMC_AUX_OK should be outputting something also but it looks like that needs 3v3 too

 

[2informaticos]

U7000 requires (internally generated) 5V to work.
And is not present in your case...