Recent build; mobo keeps rebooting

ratsa

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The computer has been humming along nicely for a month or so until today. I turned it on, and it beeped once and rebooted in 1 or 2 seconds. It kept doing this endlessly.

I opened up the case and unplugged everything. The only things connected at the moment are:

Asrock Z77 Extreme4
Seasonic 750Watt PSU
CPU fan.
Intel i7-2600K
1 RAM module (4GB Team Vulcan)

I have the power to the mobo and the CPU connected.

Same thing as before. It keeps rebooting every one or two seconds, but it no longer beeps. The only way I can tell is that the CPU fan goes on and then shuts off again almost immediately.

The debugging numbers on the mobo do not light up.

Help please. I need to know what components I should RMA. I have no other components to test.

edit: I tried the RAM stick in all 4 slots.
 

ratsa

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In order to rule out a short, I took the motherboard out of the computer and tested it on a table.

The same thing happens. The CPU fan goes on for 1 second. I hear a click and the CPU fan restarts.

I tried four different memory separately in the outside slot. So we can probably rule out the memory--what are the chances that all four sticks went bad all at once, right?

That leaves:

Seasonic PSU
Asrock mobo
Intel CPU

Is there anyway I can narrow it down and figure out which component is faulty?
 

ratsa

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I tried the paper clip test on the PSU with a molex fan attached to the PSU. The PSU passed the paper clip test for what it's worth.
 

ratsa

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Good idea. I did the paperclip test again with a molex fan attached, and the fan went on and stayed on.
 

ratsa

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I didn't realize the paper clip test was 100% indication of no trouble.

For the CPU, what can I do to test it? I removed the heatsink and reinstalled it to make sure it was in. It's pretty solid. For past month, whenever I checked the CPU temp it was around 40 degrees.
 

ratsa

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The strange thing is I get the exact same behavior if I disconnect the power to the CPU... or is that to be expected?

Bottom line--what would you do? Buy a cheap PSU to test it out? Buy a cheap mobo to test the mobo? Try to RMA all of them and pay restocking fees up the wazoo?

(It's been more than 30 days, and I don't think Asrock has an RMA policy for consumers.)
 

ratsa

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I tried each of the RAM slots.

Which components do you add to the PSU? The only thing I can think of are Hard drives.

I am feeling very discouraged right now. It feels like I have to build the whole machine from scratch.
 

ratsa

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I removed the RAM sticks, and the computer does the exact same thing. That tells me that the RAM sticks are not the problem, right?

I figure that the problem lies, in the order of probability, in

(1) Motherboard
(2) PSU
(3) CPU fan
(4) CPU

The RMA process is not helpful. Seasonic charges shipping and a $25 penalty if it they determine that the PSU is not defective. ASRock says on their website that they won't even RMA to consumer.

It seems the only option is to buy an inexpensive PSU and another Asrock motherboard and use them to determine where the problem lies. And then RMA/return/pay shipping and restocking fees up the wazoo.

If anyone has a better suggestion please let me know.
 

ratsa

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I will definitely RMA the mobo because the eSATA port was giving me problems. And if that doesn't fix it I will track down a spare PSU.

To check for CPU fan problems, should I plug in a case fan into the CPU fan port?
 

hilltopmonk

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how many hdd you got plugged in? i had a weird one where i had a sata2 and sata3 plugged in sata3 ports and the damn thing kept on cycling like yours is. moved the sata 2 to a sata 2 port and it worked fine. - did this til i updated the bios (which required the pc to work first)
 

ratsa

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I installed the new MOBO and everything is working again. It was a board that worked fine for 40 days before it malfunctioned.