820-00875 no power on. Just stop working.

[dmatto_ATC]

I have a 2016 retina 13 inch MBP (820-00875) with a problem of power.
The customer say that it was working fine and shut down.
After that never start again.
I check the board and look very fine, no signs of corrosion or burn anywhere.
The only voltage that I have is 5v at PP20V_USBC, as the name of the path is 20V I asume that should be 20v instead of 5v.
Any way I have no experience on this model and I don´t get to understand the powering by the USB C adapter.

Is there anyone that have seen this issue?

Thanks.

 

[Paul Daniels]

Does this recent video by Louis help? https://youtu.be/608unuqLWj8

 

[dmatto_ATC]

Ok. I have seen it, but actually my problem is in the charger area, no corrosion and no signs of any damage. I will try a new charger.
My ignorance is abut how to get the 20v. Is it directly from the charger? If I get only 5v from charger, is it because some signal is missing? or is that there is some voltage booster circuit that is not working?
Thanks for any clue about it.

 

[dukefawks]

If you are in the EU take this thing to Apple, they will have to honor at least a 2 year warranty!

5V from the charger can be a charger/cable or board issue. First variable to eliminate is a known good charger of course.

 

[dmatto_ATC]

Thanks. Im in Uruguay and there si no chance of any king of warranty or replacement. Any way I check with anotehr charger and not luck. Only 5V from charger.
I have been looking on the schematics and no clue about how to get the 20v back.
I will keep looking and see if I can find something.

 

[dmatto_ATC]

I found a short to ground on PPVCCCPU_S0G. I check the capacitors and they seems to be fine. I guess that the CPU is the issue. I have replace CPU from a donor board in MBP 2015 models, but never on this model.
I will try to find some fried board somewhere and try to get the replacement.

 

[Paul Daniels]

CPU and GPU power lines are low resistance. It is likely not a short.

 

[dmatto_ATC]

Thank Paul, but I get 0 Ohms resistance. I know that this lines are low resistance. But in this case its a shot to ground for sure.

 

[dukefawks]

I very much doubt that this is the issue. The 5V on the charger means the machine is not even "talking" to the charger to enable the 20V output. This has nothing to do with CPU Vcore short.

Get the schematic and board view and check if 3V3_S5_SMC is present.

 

[dmatto_ATC]

Hi Duke.
Thanks for the help.
No, 3V3_S5_SMC it is not present.
Actually I have 0,5 ohms in pp3v3_g3h to ground.

 

[dukefawks]

So short to GND. Inject voltage and see what heats up. Start low and monitor current around 1 amp something should get toasty.