All-in-One Computer DC 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
This guide applies to an all-in-one with an external low-voltage adapter. An all-in-one with a mains lead entering the chassis has a different power arrangement; identify the model before selecting an adapter or opening the display. One possible explanation is that the input MOSFET or protection stage no longer passes valid adapter power.
Stop before further damage
All-in-one units may also contain mains-powered sections that require trained handling. Guessing at MOSFET orientation can expose the board to full adapter current.
Workshop checks
- Verify the specified adapter, inspect the input socket and compare behaviour at minimum and normal load.
- 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 cold start, display brightness, processor load, sleep and repeated restarts.
For an assessment of your all-in-one computer, contact AEPC in Burswood or call 027 908 8880. Provide the model and the conditions that reproduce this problem. Workshop visits are by appointment.