[nota]

I yardsaled a 12.1 21.5'' imac mid 2011

at first try it posted an error screen with the hd not getting power
but then has refused to lite up at all

so I opened it up and tryed to check volts on the power suppy output
but finding a pin out for my exact model is not eazy [found same year 27'' pin out]
and I totally can't find a internal power supply diagram for this or any other imac

I find no 5v out at all [power for the hd]
and 11.87 v dc on the 12v lines is that near enough to work ?
and 3v on a line labeled pulse signal with no pulse just 3v steady

then checking ac input find the power button is not a 120vac switch
as power is always on to the PS 120ACV IN AND 12V [NEAR] OUT
SO HOW DOES A POWER BUTTON ''WORK'' ON A COMPUTER ?

being an apple all the parts are way over priced
a 205w ps is 150 new 100 rebuilt or 50 used
while a pc unit of the same power is 20 new
and I have no way to tell if the bad PS burned up anything else