new ASUS P9X79 PRO doesn't boot up, known good power supply

new ASUS P9X79 PRO doesn't boot up, known good Corsair AX 850 power supply. So why isn't my new motherboard booting? My system was fine with the old motherboard. Here is my story:

I just swapped out my motherboard (+ CPU and RAM), replacing an older ASUS board with this one. The board has a 3930K and 32 GB of Corsair Dominator RAM. This is the only part of my system got changed. I also added a GTX 660 vid card. Drives and the fans iin my Corsair 700D case unchanged. Power supply was working fine before the motherboard swapout.

So when I turned on the power switch on the back of the power supply, the power and reset switches on the motherboard went on. A green power LED on the GTX 660 also illuminated.

I had to add another modular cable for the power supply, for the video card. If it matters, unlike all the other cables, this one didn't "click" when I inserted it.

When I press the power button on my case, nothing happens. Nothing on the monitor. No fans turn on, not on the CPU nor the case fans, nor the power supply fan. Nada.

Is the that power supply cable? So what do I do now? :confused: :confused:

I don't thin k this is a power supply issue. I really believe you have some issue with the MB

I have seen another case where the MB needed a BIOS update before it would boot with the new 6 core CPU, which may or may not be the case. But,since you know the PSU works in another system I would contact ASUS on how to update the BIOS . It can be done even if the board won't boot.

Will it start if you use the power switch on the MB?

I don't thin k this is a power supply issue. I really believe you have some issue with the MB

 

I have seen another case where the MB needed a BIOS update before it would boot with the new 6 core CPU, which may or may not be the case. But,since you know the PSU works in another system I would contact ASUS on how to update the BIOS . It can be done even if the board won't boot.

 

Will it start if you use the power switch on the MB?

peanutz94,

Thanks for the response. (You seem to be a great source of good info. :!: )

As far as I can tell, the power switch on the motherboard acts to power down the system or reset-reboot the system.

ASUS has a way in this board to flash the BIOS even without a CPU installed. I think I'm going to remove the HSF and the CPU and then do the flash. I'll keep everyone posted.

x509

As far as I can tell, the power switch on the motherboard acts to power down the system or reset-reboot the system.

It will also power your system up too. They act no different than the buttons on your case.

So if the MB wont power up by using those buttons either , then the board is bad.

I doubt it. Create a test bench using the basic components. CPU/CPU cooler, MB, RAM, PSU, and GPU. Try to boot the system outside the case, it's probably a grounding issue within the case.

I'm afraid you're right. However, there is a sort of Catch-22 going on with this board, because my CPU is a 3930K, and support for that processor was added in a BIOS update well after the board was initially shipped.

So ASUS has this nice feature that allows you to flash the BIOS even without a CPU present. I used that feature, but the board would still not boot. So on a * different * forum, somebody from ASUS contacted me with a PM, and the result is that I'm getting a new BIOS chip from ASUS, which should arrive by next Monday. And this BIOS should be up to date. if the board still doesn't boot, then the next step is exactly what you described.

Sheesh, and we DIYers like this stuff.:D: