Apple Macbook Pro / Model A2485 / 20v and .20~.40a on usbc / 28v and .20~.45a on magsafe / no boot /

[zeydullak]

Hello,

We have a Apple MAcbook pro model A2485 that does not boot, no chime, fans dont spin.

There is no visible board damage and client mentioned it just stop working.

What should we start with looking at first.

Regards,
Zeydulla.

 

[2informaticos]

Check PPBUS_AON and 3V8_AON.
If both present and stable, check U8100 & U7700 LDOs.

 

[zeydullak]

I forgot to added this. Macbook is using 20vs and amp is going up to 1 amps and goes back to zero and looping like that. Can you please tell me if U8100 and U7700 can be issue?

 

[2informaticos]

Did you test with a battery holding some charge?

Check all secondary power rails.
You may have problems with SSD.