is it dead?: Asrock 970 Pro3 R2

[pnemeth]

Hi,

I need some expert advice.

My computer appears dead. For pressing the power switch there is a short flashing of the LEDs and a quarter turn of the fans and then it stops completely. No beep.

The computer is custom built to calculate numerical models, so it doesn't have a video card, dvd or any extra peripherals. It was running very fine and a lot in the past two years. There is no overclocking.
I left it under full load (8-core AMD FX 8350) for a week and I was away when it crashed. So I don't know what exactly happened, it was already in its dead state when I returned.

My first guess was the power supply, so I ordered a new one. It showed the same symptoms. The next guess was the motherboard itself. I started unplugging everything from it, one by one, nothing helped. In the final move I had only the CPU and its cooler on. When I unplugged the CPU power cord it came alive, the CPU cooler fan started spinning, but a second after there was a small flash of light followed by a smell of burn from under the CPU cooler, but it came from the motherboard. There is also a thick coil with only partial coverage. May it be a short circuit there? There is no burn mark or any visible defect.
I did not try to reset the BIOS.
After plugging in everything it shows the same behavior as before.

I wonder if anybody experienced anything similar and have a suggestion what is wrong. Likely the motherboard, or maybe the CPU, which is still under warranty.

Specs:
FSP 500-60APN 85+ 500W power supply
Scythe Mugen 4 CPU cooler
Asrock 970 Pro3 R2.0 motherboard
AMD FX-8350 sAM3+ CPU
Kingston HyperX Predator 8GB DDR3 RAM

 

[CountMike]

You must have some video card, that MB doesn't have IGPU as far as I can see.
Anyway, that flash should be your clue even without burn marks. There's no lights there either.

 

[pnemeth]

I used a low profile cheap video card when i set up the system. After it was working I disabled and removed it, and used remote access. Its not a problem to put it back, but likely it will not get me closer to understand the problem.
The flash tells something, but I don't want to risk too much with repeating that experiment.
There is no light.

 

[CountMike]

It's very low voltage and not much current around CPU so something has to be burned when you sow flash of light. Hope you didn't do that plugging and unplugging when power was on, even PSU has to be off with the switch in the back or unplugged from mains.

 

[pnemeth]

It was completely off.
Next week I will take it to a computer service to make a complete diagnostics.

 

[pnemeth]

After a week at the service I still don't know more. The motherboard did the same short circuit like thing at the northbridge again. The guy at the store refused to do any further diagnostics claiming that this motherboard may damage his tools. The motherboard needs to be replaced for sure, but they recommend to replace the PSU and CPU as well.
This sounds to me the easiest, safest and most expensive solution.

Instead I want to get a PSU testing tool, which takes care of the PSU. Also I plan a warranty claim on the CPU. If both the PSU and the CPU turns out to be okay, I need to replace only the motherboard.