Help finding which component of my new pc doesn't work properly

[melrief]

I brought a new computer for linux gaming composed by a MSI z97 Gaming 7, an Intel i5 4690k with a Noctua NH-U14S as cooler, 6x8GB Corsair Vengeance, a MSI GTX 970 and a Corsair CX500M as PSU. I mounted it yesterday but when I booted it, the motherboard's lights and the vents, including the graphical card ones, turn on and then immediatly off. The happens in less than one second.

I tryied to debug the reason of this problem by:

• checking that all the power wires are attached correctly
• removing everything except CPU and try to turn it on
• changing the thermal paste in case I did something wrong

but the computer does always the same, it turns on and immediately off. Sometimes, rarely, it boots correctly but even in that cases it randomly reboots without reasons.
I'm not sure how to debug this problem, do you have any idea on how to do it? I would like to understand which component is broken before sending it back. I think it's the motherboard, the PSU or the CPU, because I already removed all the other pieces without success. Also, I don't think it's a heating problem because it turns off immediately and I don't think the protection system can block everything in less than one second from the boot. Sadly I don't have another PSU to use for testing.

Do you have any idea on how to check which component of the computer could be broken?

Thanks very much

[bridgman]

If all else fails, try taking the motherboard (and maybe P/S) out of the case and firing it up sitting on a non-conductive surface. You might have something in the case touching the bottom of the motherboard.

[melrief]

If all else fails, try taking the motherboard (and maybe P/S) out of the case and firing it up sitting on a non-conductive surface. You might have something in the case touching the bottom of the motherboard.

I'll probably try that, it seems like there is some kind of shortcircuit that force the motherboard to enter safe mode for 15 seconds (can't turn it on for 15 seconds after it turn off)

[MoonMoon]

I'll probably try that, it seems like there is some kind of shortcircuit that force the motherboard to enter safe mode for 15 seconds (can't turn it on for 15 seconds after it turn off)

Such behavior rather points to the CPU running into its thermal limit. When this happens in such a short time (as you say about a second) usually you have not seated the CPU cooler correctly.

[bridgman]

Agreed - that 15 second delay seems odd, not something I would expect to see with a correctly functioning mobo and P/S.

[melrief]

I will send back the mobo, the cpu and the psu . That's sad, I waited three months for this computer thanks to Fractal cases, that I didn't get anyway because they kept changing the delivery date, and now it's not working. I hope send it back won't cost too much

[melrief]

Anyway, I moved the mobo outside the case, removed everything except cpu+fan and 1 ram and tried again. This time the mobo goes in a on-off infinite cycle. So, I guess it's the mobo.

[Kano]

Did you connect the 4/8 pin extra power cable near the CPU?

[duby229]

Anyway, I moved the mobo outside the case, removed everything except cpu+fan and 1 ram and tried again. This time the mobo goes in a on-off infinite cycle. So, I guess it's the mobo.

It's also a real good idea to reseat the CPU in the socket. The is a lever on the side of the heatsink that lets you easily unlatch it. be careful of the TIM, Thermal Interface Material, it can cause the CPU heatspreader to stick to the heatsink. If it's a cold contact it can be harder than if it's a warm contact. Once you have the heatsink off, you'll see a lever on the side of the socket that lets you easily release the CPU pins from the socket. Careful not to touch the CPU pins, take a can of air and blow out the socket, then put the CPU back into the socket. Clean the old TIM off the CPU heatspreader while the CPU is locked into the socket. Then clean the old TIM off the bottom of the heatsink. Apply new TIM, I use Arctic Silver 5, about the size of a grain of short rice in the center of the heatspreader. Put a sandwich bag over your pointer finger and rub the TIM smooth over the entire surface of the heatspreader. It'll appear like a very thin layer, It should be. Now put the heatsink back on while carefully making sure the contact between the heatspreader and heatsink is applying evenly with the TIM in between. Lock down the heatsink.

Try again.