820-02020 Liquid damage - short on PPBUS_AON.

[it-solve]

Just got this in today with liquid damage. When connected to the charger with a battery it gets 5V 0.33A and the Apple chips get very hot. Noticed it has a short on PPBUS_AON with removed F5200.

Seems like will have to buy FlexBV to be able to go through the board view. Where shall I start? Is it worth it, considering apple chips are getting hot?

Thanks

 

[2informaticos]

Check if any big coil gives same resistance to ground as PPBUS_AON.

 

[it-solve]

Only the three coils (3.8V power supply) next to the Apple chip seems to be 33Ohm with removed Fuse


Lifted them and seems all three are connected to one spot on the Apple chip side. And the short is on that side. PPBUS_AON short is gone once they are lifted up

 

[2informaticos]

Then at least one of Q5800/20/40 is shorted...

 

[it-solve]

For some reason, i could not post a bigger picture.
I've lift them up at X places and short is here


Seems like VDD of U7700. Perhaps busted u7700? Is that the Apple chip?

 

[it-solve]

You were right the one in the middle is shorted. Any suggestion what donor board I can have this mosfet on? I have A1990 and A1706 boards from never gen macs. Do you have an idea of the specs of the mosfet. AONE36196, DA37EK search didn't bring much?

 

[2informaticos]

No information at all; just buy (hopefully) new one:

2.0US $ |Nuevo Original AONE36196 AON36196 de impresión 36196 QFN10|Chips de rendimiento| - AliExpress

¡Compra fácil, vive mejor! Aliexpress.com

es.aliexpress.com

 

[it-solve]

Got the mosfets today. Slightly different markings 36196 .
Replaced the shorted one in the middle and still stuck on 5V 0.15A

Seems like the 3.8V controller is heating up to 38*C at room temp 20*C. Cant measure any other shorts

 

[2informaticos]

Do you get correct PPBUS_AON now?

One of the chips powered from 3V8_AON can be damaged by overvoltage through the burnt MOSFET; possibly U7700, or U8100.
U5700 is also suspect.