Homebuilt PC sometimes will power on, sometimes won't

[cduprey]

Hello,

So I'm having a weird issue. This is my 4th or 5th homebuilt pc. I've had it for about 6 months now. About 3 months ago it started doing this thing where when I pressed the power button nothing would happen. No beeps, no bios, no bells, no whistles, no fans moving, nothing. Literally dead. However, if I waited a couple hours and pressed the power button it would boot perfectly normally. Afterwards the PC would turn on/off without issue as if nothing ever happened. I never have any issues once the PC starts. It refuses to power on I'd say once per week where I have to wait a few hours before it powers on. I have tried different outlets, different power cords, and the result is the same. Up until today I was tolerating the issue but now the PC won't turn on at all. No bios, no fans moving, etc. I have removed all components to breadboard it. I tested the PSU alone without a load with a paperclip and nothing happened. I also tested the PSU hooked up to just a fan and nothing happened. I have also bypassed the powerswitch by removing the wires and bridging the 2 prongs. Nothing happened. Unfortunately, I don't have another system or parts to test to see if my mobo powers up with another PSU. My working theory right now is that my PSU was slowly dying (hence the intermittent periods where the PC wouldn't power on) and now is completely dead. I've never had a PSU die on me with those symptoms though so I wouldnt to ask the community if that sounded reasonable. Either way, I'm about to head to the store to buy a PSU, but in case it doesnt work I wanted to go ahead and post this question to you guys to see if you had any other ideas. Thanks for the help! Below is a list of my components:

Intel Core i7-4790K Devil’s Canyon Quad-Core 4.0GH
ZOTAC ZT-90101-10P GeForce GTX 970 4GB 256-Bit DDR
G.SKILL Trident X Series 16GB (2 x 8GB) 240-Pin DD
GIGABYTE GA-Z97X-SLI LGA 1150 Intel Z97 HDMI SATA
NZXT S340 Black Steel ATX Mid Tower Case
Rosewill ARC-750 ARC Series 750W 80 PLUS Bronze Ce
Western Digital Blue WD10EZEX 1TB 7200 RPM 64MB Ca

 

[N3rdR4ge]

definitely sounds like psu. uninstall your gpu and buy a really basic, cheap one for now. use your integrated graphics for a while while you test. buy a new one if its the issue. im fairly certain the arc series is somewhat low quality, so don't make the same mistake with a nice system like this. too many people buy budget power supplies here and have problems.

tier 1 or tier 2.

http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html
https://community.newegg.com/eggxpert/computer_hardware/f/135081/t/45344.aspx

 

[coastie65]

Hi, Strange problem. Could be a bad cap, either in the PSU or on the Motherboard.

 

[Rookie_MIB]

Don't bother buying a cheap throwaway PSU to test, I can almost guarantee that's what it is. Just get a good tier 1/2 PSU. You can get a solid one for $65-75 that'll more than handle your system, and even in the unlikely case that's NOT the problem, net result is you KNOW it won't be the PSU and you'll have a good one for your system.