System not turning on

[Spooky_Fish]

Hi

I am experiencing an intermittent issue with my set up. Sometimes my PC wont power up and others times is starts fine. Last time this occurred I decided to RMA the PSU (Seasonic G-550 PSU). However before I packaged it up to send it off I tried it again and my pc powered up and has been fine for 2 months+. The issue reoccurred last night. I had been using my PC all morning and powered it off once I was finished. Went to power it on in the evening and nothing.

I can see some LEDs on my GPU and the indicator LED's on the ethernet port light up. I can even charge my phone of the front USB panels. If I leave the power out of the PSU for an hour or so and try starting the system the fans all start then stop after about 10 seconds.

Has anyone experienced this before or something similar?

 

[Spooky_Fish]

so I have tested the following.

~ Checked for loose cables.

~ Breadboarded the motherboard, cpu and 1 stick of ram. With no power on with current PSU but does power on with a different PSU.

~ Paper clip test the 'bad' psu and the fans spin up and it appears to be working.

~ CMOS reset using both the jumper and removing the battery.

Its all left me a bit confused as to what needs to be replaced

 

[Spooky_Fish]

All original cables. Tested another power cable and directly into the wall socket.

system spec is:

Intel Core i5-4670K 3.40GHz (Haswell)
Gigabyte Z87-D3HP Intel Z87 (Socket 1150) DDR3 ATX Motherboard
Samsung 120GB SSD 840 EVO SATA 6Gb/s
TeamGroup Vulcan RED 8GB (2x4GB) DDR3 PC3-19200C11 2400MHz Dual Channel Kit
Seasonic G series 550w '80 Plus Gold' Modular Power Supply
Prolimatech Panther CPU Cooler
Asus HD 7970 Matrix Platinum 3072MB GDDR5 PCI-Express Graphics Card