If I press the power button nothing happens.

Hi,

I have a similar issue with a imac mid 2011.

On the logic board ( Main board) :

Diagnostic LED 1 goes ON, this seems a power-OK led to me, I measure 12v on the supply.

If I press the power button nothing happens.

I detached all peripherals, sdcardreader, camera, audio, hdd, speakers, etc. Still nothing.

I checked the power button, the button and cables are OK.

Question:

Does it need memory in the banks to power on, ( LED #2) ?

Could it be a faulty CPU or GPU, does it need that to power on?

could I detach the video card an test power without it?

The thing is I don't feel like replacing the logic board, its to expensive, I just wondered if there is any information about the "logic" which turns on the power, could I override it, so I can see where the smoke comes from ? :)..

Regards,

Guido