New Build - Strange Behaviour

[The Donut]

Finally finished a new build but am experiencing a weird issue.

When I power on it shuts off almost immediately and 3 seconds later comes on again by itself and boots fine.

I've changed and removed all the hardware down to the motherboard, cooler and power supply.

I changed the power supply and it does the same thing. I'm told, that some motherboards do this as normal behaviour?

I've made a quick video: https://vid.me/DyAv

Board is ASRock Extreme7+, i7-6700k and corsair 750w psu

Any ideas?

 

[hdfreedom]

Sounds like you know what you're doing and have tested appropriately.

I bought a Gigabyte GA-Z77X-UD5H awhile back that would do the same thing. No rhyme or reason, just did.
I've got 2 other of those boards that I bought and have had no problem with them at all.

I guess what I'm saying is "it happens". Just RMA it and move on my friend.

 

[Deleted member 88227]

Remove the motherboard from your case. Place it on the box it shipped in and/or a non conductive surface. This will simply eliminate a short caused by the case. If the symptoms continue then it's time to RMA the motherboard.

 

[The Donut]

Remove the motherboard from your case. Place it on the box it shipped in and/or a non conductive surface. This will simply eliminate a short caused by the case. If the symptoms continue then it's time to RMA the motherboard.

If you see from the video, this is all currently stored on a rubber mat - no case.

 

[Dangman]

Normal behavior. I see it all the time with the GIgabyte motherboards we use at work. Although I'm not sure if I've ever seen it happen with the higher-end AsRock motherboards.

But that's just the double-boot issue. Not a serious problem but definitely a slightly annoying one. Up to you if it's annoying enough to RMA.

 

[The Donut]

I've spoken to a few people and apparnetly this is normal with a large number of boards (particular ASUS MAXIMUS boards)

The issue that concerns me is why the old power supply (Thermaltake Toughpower XT 1275W) no longer boots in the on/off/on sequence and simply gets stuck at on/off - but a new Corsair 750W power supply works fine.

The Thermaltake one was working and an hour later, was not. Unless it has some sort of protection built in and the on/off/on sequence is triggering it..