Common phone-charger PSU failures, pattern from 2 years of repairs
Posted: Tue May 12, 2026 4:54 am
Sharing yung patterns na nakita ko sa shop. Cheap phone chargers and small wall warts ang pinaka-common na PSU failures we get.
Top 3 failure modes (most to least common):
1. Capacitor failure, yung mga electrolytic caps sa output stage, dries out after 1-2 years of heavy use. Symptom: device works for a few minutes, then loses voltage / device resets. Open the charger, you'll see bulging or leaking caps.
2. Optocoupler failure, yung component that provides isolation feedback to the primary side. When this dies, output voltage either spikes or goes to zero (depends on the topology). More dangerous kasi pwede mag-overshoot at sirain yung naka-charge na device.
3. MOSFET failure, usually gradual. Gets hot, then dies. Often takes the gate driver IC with it. At this point, more economical to throw away and buy a new charger than repair.
Lessons:
Top 3 failure modes (most to least common):
1. Capacitor failure, yung mga electrolytic caps sa output stage, dries out after 1-2 years of heavy use. Symptom: device works for a few minutes, then loses voltage / device resets. Open the charger, you'll see bulging or leaking caps.
2. Optocoupler failure, yung component that provides isolation feedback to the primary side. When this dies, output voltage either spikes or goes to zero (depends on the topology). More dangerous kasi pwede mag-overshoot at sirain yung naka-charge na device.
3. MOSFET failure, usually gradual. Gets hot, then dies. Often takes the gate driver IC with it. At this point, more economical to throw away and buy a new charger than repair.
Lessons:
- A charger na bumibili ka for PHP 50, hindi mo pwede expect na tatagal ng 5 years
- A 'good' PHP 250-400 brand charger lasts 3-5 years easily kasi mas matibay yung components
- If you're selling devices, always recommend customers use proper-rated chargers, hindi yung bottomless pit ng dollar-store ones
- Recycling old chargers, keep yung good capacitors and ferrite cores. Useful for hobby projects.