Hi!

I finally tested the PSU on the same motherboard as before BUT now with CPU, GPU and RAM. Works like a charm !
Seemingly, all ATX PSU doesn't behave the same way depending on the output conditions.
I compared with another PSU, a Seasonic FOCUS+ Gold which is LLC based and has several buck post converters after the main one. On this one, the naked motherboard (without CPU, GPU, RAM) could be powered without any problem.

Anyway, I consider this PSU as OK and it will be used for testing various old motherboards. Output caps are still in good shape and voltage...

Thank you so much for your answers.
I didn't fiddled more on this PSU since last week.

I was wondering, maybe this could be a bad snubber/damper on the secondary winding...
[U][B]With no load[/B][/U] at all, the duty cycle is at his minimum value. If the snubber resistor/capacitor is broken, some overshoots on pulses could appear and "mislead" the regulation, reducing again the duty cycle to maintain 12V at the output.
Maybe I will check that...

Otherwise, nothing wrong with an IR camera, no hot spots.

JBThank you so much for your

Hi,

A colleague gave me an apparently ill CORSAIR CX600.
He told me that he heard a banging noise, and smelt the magic smoke.
After tearing down the PSU, no burnt component, everything seems OK, but the PSU often refuses to stay ON. When shorting PS_ON to GND, the fan spins a bit a finally stops. No output voltages.

I tried to treat some apparently bad solder joins and finally it seems to work OK... on the 12V and 5V rails!
It's another story on the 3.3V rail...

I have some devices to test deeply PSUs (scope, AC source, electronic load)...