Gigabyte Z77X-UD3H motherboard problems

[ihong5]

Hi, I bought a new Gigabyte Z77X-UD3H motherboard along with i5-3570K cpu
I've been having trouble trying to get this thing to work..
first time I bought them, I installed the motherboard and CPU along with the heatsink,
and finished building the system.
The CPU fan would NOT run!! (I don't know why)
so I thought I got unlucky and picked up a defect so I went to microcenter and bought another one (same motherboard and same cpu)
I've had the same problem the second time as well...
so I went back to microcenter and came back with the same motherboard and cpu for the THIRD time and now, I left the cpu alone as it is and only tried to plug in the cpu fan WITH a new power supply (which I thought might be a problem)
now the motherboard is turning on and off at like 1-2 second interval
I didn't touch the cpu yet (not even the cover) so it should be in a good shape
any ideas??? i'm sick and tired of driving 40 miles back and forth returning and exchanging these parts when I know for sure they are working perfectly fine... AND on top of that I need a working desktop computer ASAP
can anyone think of what I am doing wrong?

 

[jordonc]

It seems pretty unlikely that 2 in a row had bad cpu fan connectors, and makes me wonder if you might have plugged the cpu fan into the DAJP1 connector on accident. All I can say is recheck to make sure all of your cables are plugged into the correct spots. Looking at my motherboard and cpu (same as yours), everything is pretty clearly labeled, so you should be able to check it pretty quickly. You really only need the cpu and cooler, RAM, and psu installed to get it to post. I suppose you could post a pic so we could check it for you. But just to make sure, you do have the CPU installed, right?
Because you said:
"I left the cpu alone as it is and only tried to plug in the cpu fan WITH a new power supply (which I thought might be a problem). now the motherboard is turning on and off at like 1-2 second interval."

The mobo would most definitely not stay on without the cpu installed because it wouldn't post. http://www.tomshardware.com/forum/323005-31-safe-power
Hopefully someone with a little more troubleshooting experience than me comes along with more suggestions.

 

[ihong5]

I see your point there, and yes when I said "I left the cpu alone as it is and only tried... blabla", I meant I didn't install the CPU, meaning the CPU was still factory sealed. Now I learned that mobo doesn't turn on without the cpu installed, thanks to you.
And I didn't plug the cpu fan into DAJP1 (I don't even know what that connector is for anyway), but I did try to plug into sysfan1, 2, 3, 4 connector... obviously same result.
Finally I did get it to work; like you said "it seems pretty unlikely that 2 in a row had bad cpu fan connectors", you're right, neither cpu nor the cpu fan connector were bad.

I think the real problem was the screw I used to install the motherboard. Because the first 2 attempts, I installed the motherboard using the screw with wider head, like the ones you use to install the power supply (which is because that screw had a secure fit with the brass mounts). On my third time, I tried using the smaller screw with narrower head (which still did the job, just the fit didn't seem as secure as the other ones) and that did it. So... it seemed like my mistake

still, I appreciate your feedback.

 

[jordonc]

I'm just glad that you got it figured out. Maybe that first screw was causing a short somewhere in. And I have no idea what that other 4-pin connector is for either. I just saw that it was close to the CPU fan. Enjoy your new build!

 

[ihong5]

Best answer selected by ihong5.

 

[nikorr]

This topic has been closed by Nikorr