Small-Form-Factor PC Power Supply: Unstable power-good signal | Auckland
Pattern to record: Startup loops or resets occur before POST despite normal unloaded voltages.
Identify the supply and load
Compact desktops may use proprietary PSU shapes and connector wiring. Check the exact system and supply part numbers before substitution, and inspect airflow without opening the mains-powered supply. One possible explanation is that the supply does not reliably indicate that output rails are ready.
Mains and connector safety
Compact supplies retain hazardous charge and have model-specific pinouts. Forcing the signal high can expose the motherboard to unstable voltage.
Workshop checks
- Inspect airflow and connector condition and compare rails during a controlled combined load.
- Monitor the power-good timing and rail stability through startup.
Repair and loaded verification
If the checks support this cause, replace the supply or repair its control stage professionally. Verification should cover cold and warm start, processor load, storage activity, USB load and sleep.
For an assessment of your compact desktop, contact AEPC in Burswood or call 027 908 8880. Provide the model and the conditions that reproduce this problem. Workshop visits are by appointment.