newly built pc boots up then shuts down after 30 seconds or less

[mr_chops345]

as per title, pc worked perfect for a couple of months then this issue suddenly happened. Now run time decreases after each start up till eventually it starts and suddenly shuts down after a second or 2. Ive pulled everything ( testing each component by itself as well as testing the system after ive removed an item ) all same result. Its been removed from its case and same result. Its down to motherboard and cpu now with the same result. Ive tried a different psu after thinking that it was psu.
specs are as follows
amd fx8350
asus 970 pro gaming/aura motherboard
corsair dominator ddr3 2133mhz @16gb
asus r9 390x strix
corsair ax860i
corsair x100i cpu cooler
phantecs ethoo evolve case.
Running Win10 64bit

 

[alexoiu]

Probably a board issue, but I'd RMA both board and CPU.