Chosen Solution
I am having powe issues with my iMac. I get nothing when I hit the power button. I have installed two different power supplies thinking maybe the first one was DOA, but not the case. There are also no LED lights lit on the logic board when I have it plugged in. I thought for sure it was a PS issue but I was wrong. Any help is appreciated. I have had this computer a little over a year and didn’t purchase Apple Care. Also, prior to this all happening I was hearing buzzing noises out of the back of the screen. I have read that this is a known issue.
You’ll need to trace out with an Ohm meter from the case power socket to the power supply the cable harness and connectors. I’ve never seen a cold dead system that didn’t have either a bad power supply or a basic AC or DC power harness defect. Don’t forget to check the power on button cable connection. Again, are you sure you have a working power supply?
It sounds silly but is it plugged into a outlet that is controlled by a light switch. If so, make sure the switch is on or plug it in another outlet. If it is plugged into a power strip , make sure it is on. I have had this exact silly thing happen to me. Good luck.
