Computer starts 20 seconds after pushing start button

[Starmaderp]

Hey guys I have a peculiar issue which has driven me towards asking for help on here because I can usually troubleshoot my machine however this time I am stumped. It was working fine one week ago but I've been away for Christmas, now as I have returned I try to turn on my computer after a week and zilch.

Initially my computer would not start at all and after troubleshooting I took the motherboard out of the case and began trying to breadboard it. Now as I was browsing google for solutions I discovered 20 seconds after me pushing the start button on my motherboard, all my case LED's light up, all my fans spin including the inbuilt mobo fan, then half a second later it instantly turns off. Then it begins looping, turning on every 5 seconds then instantly shutting off. I have removed everything but the CPU, CPU fans, 8 pin CPU and 24 pin power supply.

Mobo: ASUS Rampage IV Extreme x79
CPU: Intel I7-3930k
PSU: Corsair 850W
Ram: 4x4gb 2133mhz 1.65v

Any help is much appreciated and I will try everything you guys can suggest to me.

Thanks for reading and all questions will be answered within 10 minutes

 

[Starmaderp]

Quick update, I left my psu turned on and now when I pushed the start button it instantly turned on for half a second then shut off. Then began the whole boot every 5 second thing again. So it's boot looping and I have no idea why, I have replaced the battery on the mobo too.

 

[reedo_43]

My first guess would be a failing power supply.

 

[Starmaderp]

That was my thoughts too tbh

 

[Starmaderp]

Is there a way to check a power supply? Anymore suggestions would be great!

 

[smorizio]

sounds like a bad cap or vrm on the mb. look on the mb for any swollen caps. use a volt meter watch the power good line see if it stays within atx spec when the pc is turned on. make sure your cpu and ram are seated. try one ram stick to see if it a bad stick of ram. make sure the mb has the newest bios on it to rule out a bios bug.

 

[Starmaderp]

sounds like a bad cap or vrm on the mb. look on the mb for any swollen caps. use a volt meter watch the power good line see if it stays within atx spec when the pc is turned on. make sure your cpu and ram are seated. try one ram stick to see if it a bad stick of ram. make sure the mb has the newest bios on it to rule out a bios bug.

Tried this and no luck :/