iMac 27” 2011 led 1 on, goes off by pushing the power button

I thought someone could benefit by the info that I solved this issue by disconnecting the wifi card.

I already tried replacing the power board, ram and hd/ssd to no avail. Replacing graphics card didn’t help either.

I’m curious to see if the problem will reappear once I replace the wifi card. In case, will let you all know.

Update: wifi card replaced, but the problem persists. The iMac will work perfectly only without wifi card.

@danj any hint?