Question Computer is not turning on at all after power grid outage


Apr 20, 2018

Yesterday there was a power outage in my city (while my computer was running) and after the power turned back on my computer is no longer turning on at all. There was no lightning storm or anything like that.
Since the breakers in my apartment tripped after the power came back on, I assume there was maybe some power surge present, but all other computers and devices I have at home keep working without any problems.

When I press the power on button on the case, nothing happens at all, which made me think that maybe the PSU got blown up, so I disconnected all wires from it, plugged the power cord back in and shorted together the green wire with a ground wire and the PSU fan started spinning. I also measured all the voltage outputs (3.3v, 5v, 12v) with a multimeter and they are all correct, so it seems like the PSU is fine. Could it be that a power surge got through the PSU and fried the motherboard without actually damaging the PSU? That should not be possible right? Not without at least blowing the PSU's fuse or something.

So maybe the power on button is damaged, I thought (unlikely though). So I pluged the PSU back into the motherboard and shorted the green and black wire together once more to simulate pressing of the power ON button on the case and the LEDs on the motherboard flicked very briefly (like 0.1s) and the fans twitched ever so slightly once, but after that, nothing. If I repeat this (short the green and black together again) i get the same result, short blink and a fan twitch.

I tried to remove the RAM, HDDs and the GPU, so all that is hooked up to the PSU now is the mobo, CPU and fans, still nothing.

So what am I looking at here? Is the mobo destroyed? I have no other PSU to try without ripping apart my other computer which I want to avoid doing.


Are you sure that the current wall outlet is working? Test with a lamp or with your multi-meter even.

Are you plugging the computer/PSU directly into a wall outlet or is the power connection via a power strip or some form of surge protector?

Surge protectors that have "done their job" protecting the attached devices can be damaged and fail as a result.

If there are any such devices check that they do not have their own independent breakers or even a fuse of some sort. Remove any such devices and plug the computer directly into the wall outlet.