Help a noob - Dead Mobo? Sabertooth X99 and i7 5820K

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DudeItsMe

[H]F Junkie
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Aug 10, 2004
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EDIT: Board has been sent in for replacement.

I'm troubleshooting a new system that I am having problems with. IT booted ONCE the first time and never since then. I made it to BIOS and restarted because it wasn't showing my thumb drive.

Mobo/Proc are Sabertooth X99 and i7 5820K.

I have reduced to the minimum of graphics cards, one memory stick, and CPU.

It will not give any POST beeps and the diagnostic LEDs will not illuminate either.

Right now what has me baffled - if I plugin in the 24 pin ATX connector it will turn on and run for a bit. If I ALSO plug in the 8 pin CPU connector (ATX 12v), I can hear the power supply turn off after like one second.

The board also has a 4 pin CPU connector right next to the 8 pin. From what I could find, I am only supposed to use one, not both. Regardless of which I plug in it will not work. I haven't tried to plugin both at once since I don't have a cord for both... that would result in a 24 pin ATX power connector, 8 pin, AND 4 pin... surely that's redundant? :confused:

Any idea where I'm going wrong here? Why would plugging in the 8 pin connector cause the power supply to restart?
 
Last edited:
OK,
You needed to determine of the power supply you got is bad.

I would pick up one of a pc power supply tester, and check the numbers.

You could also, try the same system with another power supply (with enough power) if you access to one.
This is the first motherboard i have seen with both 4 and 8 pin. Normally i would say you just need the 8 pin, hopefully someone else can tell you more about that.
Good luck
 
A new PSU did not help. I was not able to run it with a graphics card since my other PSU is less powerful, but it did exhibit the same behavior. With a 24 pin plug plugged in, the CPU HSF will run steadily. Once I plug in the 4 pin, it will cycle within a second.

Could the processor be causing this problem? I've reseated it more than once. I really have no way to tell if the processor is bad... but I would think the CPU LED would light up if the motherboard made it that far. The motherboard is just basically going nowhere it seems.
 
I have read that these X99 boards occasionally kill the CPU, with similar symptoms. Your CPU could have been assassinated.
 
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