Hi Jonny, thanks for trying to help.
So when AC is loss, the PSU will not start again until you jump the PS ON pin? = Truth
But you can turn the PC "off" in Windows and it will start every time, correct?= Incorrect
No, I meant: even when you shutdown the pc within windows. The PSU will not have any power out (I have not measured with multi, but no indication or LED or fan power on pcmb or case or otherwise) until jumped. After shutdown you can hear a tick noise and then the unit is "dead".
You said six different boards it has this behavior? All six boards the same kind, or...?
No tested from ivy Z77 to current, MSI, Asrock and Asus.
I get the feeling this is a sensor related problem, that might stem from a faulty cable? Can you help me with a method that I might use to do some testing to identify the problem?
Maybe a quick video might clear allot of the question right up.
Beeg hug.