Hello,
I would appreciate if someone could point me in the right direction diagnosing a fault with a PFC PSU and potential things to check.
Dell/LITEON 53WG5 PS-3231-9DA PFC PSU , works for a few seconds and turns off using the relay. (under load or without load, same behavior).
After that it will not turn on for about 30 seconds and the same behavior persists.
The TOPSwitch TOP266VG chip is very hot, even without load. I suspect it goes into thermal protection mode or some other protection mode (unclear why).
The capacitors are visually ok. Tested most of the capacitors out of circuit, all fine. Transistors are not shorted, rectifier ok, discrete diodes ok, the capacitor shows 380 volts dc (meaning boost and rectifier work).
Didn't find dry solder joints, output voltage while the PSU is on is normal, 12v, 5v.
Tried looking for the schematic but couldn't find it.
Pictures attached, much appreciated.