Turns off sometimes, no power to fans/peripherals.

Hello everyone I recently built a new pc using the asrock z97 killer fatality board, however my PC would sometimes turn off automatically and refuse to turn back on. Power light would be on but the rear/front fan and the cpu fan wont be on(things powered via the motherboard). No BIOS screen and no peripheral lights.

The first time this happened was roughly a week after I built the PC. I took everything apart reapplied thermal paste and slowly plugged in the various pieces. Unfortunately it seems random when the PC would start. Sometimes It would do it when only one of the RAM sticks are on sometimes while both were on. Sometimes it wouldnt turn on with the graphics card, while otherwise it does. Eventually It worked with all the components on. Because this board is smaller it only used I believe 7 of the 9 standoffs the case comes with, but all 7 of those are in and tightened and screwed properly.

The second time it happened I took out everything except the cpu and cooler and unplugged everything except the 24 pin atx power, at which point the power supply made a rhythmic clicking noise, which apparently is the voltage regulator? After various things were removed( never the CPU and cooler) and re-added It is now working again, but I have no doubt this will happen again because I cant imagine anything I did fixed anything. I do have parts from my older PC but the motherboard wont work with the i7 I have. I think the issue might be with my motherboard.

I also have two extra fans which are antec 3 speed fans which I salvaged from my old PC. Cant imagine theyd affect anything but more info the better. There are no BSOD or anything of the like, the temps are pretty good as well. I had the CPU overclocked to 4.5 at around 1.243 volts and while synthetic tests were hitting mid 90s as max temp I never go above mid 70s max while normal day to day use( gaming, and browsing). Its also summer where I live so ambient is slightly higher. I have removed the overclock for the moment just to be safe. I feel like I shouldn't run the PC as is but I have no choice. I should mention I also dont have external speakers so I cant listen to the POST beeps. This is an extremely difficult problem to diagnose as well since, I cant reproduce it, I have to wait for it to happen again(fingers crossed it wont). If it happens again I will probably RMA the board.

the following is my full parts list. PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i7-4790K 4.0GHz Quad-Core Processor (Purchased For $330.00)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (Purchased For $31.00)
Motherboard: ASRock Fatal1ty Z97 Killer ATX LGA1150 Motherboard (Purchased For $107.00)
Memory: G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-1866 Memory (Purchased For $95.99)
Storage: OCZ ARC 100 240GB 2.5" Solid State Drive (Purchased For $69.99)
Storage: Western Digital Red 4TB 3.5" 5900RPM Internal Hard Drive ($139.00)
Video Card: EVGA GeForce GTX 980 Ti 6GB Superclocked+ ACX 2.0+ Video Card ($679.99 @ NCIX US)
Case: Fractal Design Define R4 w/Window (Black Pearl) ATX Mid Tower Case (Purchased For $103.99)
Power Supply: Corsair 750W 80+ Platinum Certified Fully-Modular ATX Power Supply (Purchased For $99.99)
Monitor: QNIX QX2710 Matte 60Hz 27.0" Monitor ($285.00)
Other: ADATA Value-Driven S102 Pro Effortless Upgrade 16GB USB 3.0 Flash Drive (Gray) Model AS102P-16G-RGY (Purchased For $10.99)
Other: Rosewill RTK-002 Anti-Static Wrist Strap Components Black, Yellow (Purchased For $7.00)
Other: DIsplayport to DVI active adaptor ($125.00)
Total: $2084.94
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-06-22 22:23 EDT-0400

Ignore the 980ti, atm im using a gtx 560ti.

any help with this would be greatly appreciated.

Thanks, and good idea. The only reason I haven't done that so far is because it is a plat 80+ rated and had very nice reviews, but hey anything can have defects no matter how well its made. Its just annoying because I basically have to wait for a crash before knowing if it was fixed. Also of note are the two antec fans I have are connected via molex so not through the motherboard, and those will continue to run, just something to keep in mind.

Edited by covertskippy55 - 23 Jun 2015 at 11:54am

Hmm, good thinking, I wonder if there is a way to find out, I could call the power company I suppose. I do live in an apartment complex with AC so it could be a possibility.

Power problems from the electric utility are very rare in the USA. If the problem was caused by a reduced AC voltage, that would more likely be caused by inadequate wiring in the building. You would also see the lights dimming in your apartment if the AC voltage was low. Other electric devices like a TV or stereo would also be affected by low AC voltage, more so than a PC could be.

PSUs like that Corsair can be used world wide, as they automatically adjust themselves to work with the AC voltages used in various countries. My Seasonic PSUs are the same type of design, AC input voltage can be between 100V (Japan) and 240V (Europe). The AC voltage standard is 120V in the USA, and since the PSU is fine down to 100V and a bit less, the voltage variation would need to be quite large, and of the kind referred to as a "brown out", which would affect large areas. Or if just in your building, it would be obvious that the lights were dimming in both cases.

Regardless, I agree either the PSU is the problem, or something else is causing the PSU to be acting unusual, and its protection circuits are activating. The rhythmic clicking sound you mentioned is not from a voltage regulation circuit, but from a relay that is "chattering" as it is opening and closing rapidly for some reason. That sound is a clue, and so is the fans on the molex connectors still running when the board is apparently shutdown.

If the board shut off the PSU the fans on the molex cable would also be off, but they were still running. That would seem to indicate the PSU sensed a fault like a short circuit in one of the power rails in a cable connected to the board. My Seasonic PSUs have protection circuits that the manual states will only shut off power on the cable(s) where a fault is detected. That seems to be what is happening with your PC.

Power/PSU problems can be tricky, and I would not rule out a defective PSU yet. You mentioned the number of standoffs used by the new board is different than your previous board, in your first post. Standoff patterns are different for different boards, any chance one of the extra ones (9 - 7 = 2) are shorting the board to the PC case, which is also the ground connection?

I would start looking for any potential short circuits from standoffs, or any wires being pinched between parts, or bare wires or the metal on connectors being exposed and touching or barely touching something else. Trying a different PSU is still a good idea, but if the symptoms are the same or worse, then it seems like there is a short circuit between the board and the case.

Ok, I have preemptively replaced the power supply with my old 650watt one, and I'll probably start the RMA proccess. Last night when i turned off the PC it was doing the clicks again, with the new(old) power supply its at least not doing that.