Paul B. Webster wrote:

I'd be interested (as may many of the list) to know what you find, and
what you intend to do.  One detail I have figured is that motherboards in
general default OFF.  If however you short the front panel button,
they default ON but of course you can't turn them off then.
______________________________

Paul
one way to do this is to use a 10u Cap across the switch input to the board
with a diode cathode  to +5 volts to discharge cap at switch off.
then when machine is switched ON cap acts like short and pc starts up.
But my bios for a new mother board I'am using now lets me select switch mode
as options instant off. delayed off and machine to start when power is
applied.