USB-C Laptop Charging Input: Failed reverse-polarity protection | Auckland
Pattern to record: The adapter is recognised mechanically but no protected voltage appears beyond the input stage.
Identify the input design
Identify which USB-C ports on this laptop actually accept charging. A data-only USB-C port and a charge-capable port can look alike, and the charger and cable must support the laptop’s required power level. One possible explanation is that the input MOSFET or protection stage no longer passes valid adapter power.
Stop before further damage
Remove debris without metal tools and do not force a loose USB-C plug. Guessing at MOSFET orientation can expose the board to full adapter current.
Workshop checks
- Test a known compatible PD charger and cable in both orientations, then separate connector damage from negotiation and board faults.
- Compare gate, source and drain conditions using the correct circuit reference.
Repair and power verification
If the checks support this cause, replace the failed protection device after confirming no secondary short remains. Verification should cover both orientations, supported power levels, sleep, battery transition and sustained charging.
For an assessment of your USB-C laptop, contact AEPC in Burswood or call 027 908 8880. Provide the model and the conditions that reproduce this problem. Workshop visits are by appointment.