HeyWatchOutDude
Member
Model: A2681
Board: 820-02536
Symptom (with charger only and battery/charger):
The device continuously power loops between 5V and 20V (5V → 20V/0.01-0.12A → back to 5V → 20V/0.01-0.12A …).
Measurements:
Notes:
Board: 820-02536
Symptom (with charger only and battery/charger):
The device continuously power loops between 5V and 20V (5V → 20V/0.01-0.12A → back to 5V → 20V/0.01-0.12A …).
Measurements:
- PPBUS_AON: 12.26V → 11.97V → 6.6V → 12.26V ... not stable
- PP5V_AON: 5V stable
- PP3V8_AON: 3.8V stable
- PP3V3_AON: 3.3V unstable
- PP1V8_AON: 1.8V unstable
- PP5V_S2: 5.1V unstable
- PP3V3_S2: 3.3V unstable
- PP1V25_S2: 1.25V unstable
Notes:
- U5200 (489900A6) has already been replaced with a known-good part. No change in behavior.
- U5200 current sensoring resistors are fine. (all have 0 ohm)
- Device is not detected in DFU mode.
- The board had prior liquid damage, was repaired, and worked for approximately 4–6 months before failing again.
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