Z170 Gaming K4 - dropped dead

For about a year I used the Z170 Gaming K4 motherboard without problems. 3 days ago this happened:

1. The computer turned off unexpectedly from one second to another. I was just browsing and I didn't overclock anything, so I doubt it was a temperature problem.
2. After hitting the power button, nothing started. No fan movement, no signal on the monitor. I disconnecting the power supply and slightly rocked the computer out of despair. After reconnecting the power supply the computer went in a cycle where the fans started moving (and the LED lighted up) for a split second, stopped again and repeated. All this without me touching the power button at all, just by connecting the power cable outside the power supply unit. I have never seen something like this.
3. After some more dis- and reconnecting and rocking, the computer booted up normally and was fine for a while.
4. The next day the same happened again out of nowhere, it went again in this strangle cycle of powering up and shutting down. But in the end it went back to dead mode and stayed there since.

What I tried so far:
- I dis- and reconnected every single accessible connection to make sure nothing is loose.
- I tried a different power supply unit (which runs fine with another computer).
- I tried a different power switch (which runs fine with another computer).
- I removed GPU and all drives.

Nothing. Everything dead. No fans moving, no LED lighting up, no signal on the monitor, no sounds. I can only assume there is something horribly wrong with either the motherboard or the CPU.

What else could I try?


Edited by Osmium - 26 Jul 2017 at 9:51pm

You could try removing the CMOS battery for a complete clear of the UEFI/BIOS, while moving the jumper to the clear position at the same time. Or try replacing the battery.

That you could get the board to work, at one point, by moving the PC case, might indicate a short circuit of the board somewhere, usually at the bottom. Such as a screw or other metal part that is loose within the PC case.

Usually a dead CPU will still allow the board to power on.

I've had a bad drive cause the PC to shut off shortly after it was turned on, but you said you removed all the other components, correct?

You did not mention doing anything with the memory, which is the only reason I mention it.