What the customer sees
To the customer, this kind of case is simple and brutal: the phone is dead. No useful signs of life, no normal charging behaviour, no clear clue from the outside.
That is exactly why dead-phone cases should not be treated as a guessing game. The outside symptom is broad, but the underlying board fault can be very specific.
What made this case deceptive
The bench note behind this case was clear: it looked like a broad no-power fault at first, but isolation work showed it was actually tied to baseband power management.
That matters because replacing random parts around the device would not address the real cause. The repair only becomes sensible when the fault is traced properly.
What the real fault was
The root cause recorded in the Tech2Fix knowledge base was a shorted BB PMIC. In plain English, that is a failure in the baseband power-management side of the board.
The key measurement note was simple but decisive: baseband PMIC short detected.
What fixed it
The recorded fix for this case was replacement of the BB PMIC. The case outcome was logged as Fully Fixed, which is exactly the kind of result that makes board-level diagnosis worth doing before writing the phone off.