MOBO or PSU issue in new build, need advice

RaBaTaJ

Honorable
Mar 26, 2013
5
0
10,520
MOBO : GIGABYTE Z97X-GAMING GT
Hello everyone,

I am building this new computer and am pulling my hair off over it... Please see the specs below :

MOBO : GIGABYTE Z97X-GAMING GT

CPU : INTEL CORE I5 4690K HASWELL REFRESH

GPU : MSI GEFORCE GTX 970 GAMING 4GO

RAM : G.SKILL 8GO DDR3 2133MHZ CL9 RIPJAWS X (x2 -> 16GB TOTAL)

PSU : LEPA 500W MAXGOLD

COOLING : COOLER MASTER SEIDON 120

CASE : COOLER MASTER SILENCIO 652S

After assembling everything, the computer wouldn't start (on pressing the POWER button, LEDs flashed and fans turned on for half a second, then nothing).

At some point I managed to get the computer to boot and even to install Windows 7 with the GPU removed. But after installing Windows I could not boot anymore.

After that I could not get it to boot at all (tried different configs, single RAM, GPU/no GPU, etc...) so I decided to try and use my CORSAIR CX430.

With the CX430 I can now get it to start consistently without a hard drive on, but as soon as I plug another SATA device to my PSU I get back to step 1 (LEDs flashing + fans turning on for half a second then nothing), even if said SATA device is not plugged to one of the MOBO's SATA ports.

Without a hard drive, the computer boots up and allows me to access the BIOS ; but as soon as I plug another SATA device to my PSU, the computer won't boot anymore (I've tried every single SATA setting in the BIOS).

Both PSUs (the LEPA 500W and the CORSAIR CX430) have been tested and are working fine on another computer. I believe that if the CPU were faulty, I never would've been able to boot at all (correct me if I'm wrong here), so the only thing I'm left with here is the MOBO, which I think is somehow broke and will have to be returned.

GPU, RAM and PSU have all been tested on other computers and seem to work fine.
I could not check the CPU (used to be AMD so I have no other Intel MOBO), nor can I really say for sure that the MOBO is faulty although this seems to be the best lead I have.

Can you guys please enlighten me or confirm my diagnostic ?

Thx a lot !!