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Gigabyte motherboard won't POST, phase LEDs all on

Last response: in Systems
July 15, 2011 8:08:55 PM


I've had my PC nearly a year and it suddenly decided to stop booting. It just sits there, with the phase LEDs all on, and doesn't beep or display any video output. There are four lights displaying green and yellow next to the RAM slots, I think they're the DDR voltage. Also, the lights on the mouse and keyboard never come on.

I've unplugged everything and breadboarded the motherboard, the only things connected are the CPU/HSF and PSU. Also, there are no memory warning beeps with the RAM removed (and before you ask, yes, the speaker's attached :) 

These are my specs:
* Gigabyte X58A-UD3R
* i7-930
* Scythe Mugen 2 Rev B
* Corsair HX1000W PSU
* Corsair XMS3 1333MHz 7-7-7-20 6GB
* inno3d GTX480
* Case: Coolermaster CM690 ii advanced

The CPU was (moderately) overclocked but I reset the CMOS.
Is it worth getting a multimeter to test the PSU? I find it hard to believe that such a powerful PSU would fail, especially one that got such good reviews.

Any advice would be greatly appreciated.
July 16, 2011 7:32:25 PM

July 21, 2011 9:13:39 AM

Same problem. On for a few seconds, then off again, then on again, fluctuate, cycles, won't post.
Motherboard is now sitting on the box it came in to isolate a possible short.

All brand new parts.

gigabyte z68xp-ud3-issd
intel core i7 2600 (with intel cpu fan plugged into CPU_FAN plug)
kingston kvr1333d3d4r9s/8g (in slot DDR3_1)
kingston kvr1333d3d4r9s/8g (in slot DDR3_2)
ritmo force 1500w gaming power supply to ATX
ritmo force 1500w gaming power supply to ATX_12V_2X4
power switch connected
reset switch connected
power led connected
hard drive activity led connected
hdmi port into television

Everything else is now disconnected.
I have re-seated everything including CPU.
I have now removed battery and will give this a shot.


PS: I've only read bad things about ritmo force 1500w gaming power supply.
Related resources
August 7, 2011 12:53:59 AM

I hae the same issue with a brand new machine I picked up yesterday. It has booted a few times without any issues, enough for me to get windows 7 on it. But now it seems stuck. Although while I am typing this on my other computer it just made it to the bios again (I love hearing that beep).

I have:
gigabyte GA-Z68XP-UD3
i5 2500K
G.Skill Ripjaws 4 GB loaded in slot 1
OCZ fatal1ty 750W gaming power supply
gigabyte 6850 OC
seagate 1tb 7200rpm sata III
LG dvd r/w drive

Has anyone gotten anywhere with this? It's pretty darn frustrating!

August 7, 2011 5:24:20 AM

Found the master thread for this issue. Have a read through, I haven't found a solution yet but it seems like when one is found it'll definitely make it to this thread because a lot of people are involved in it.

Good luck to everyone, if I find a solution I'll post it to this site as well.

July 3, 2012 10:29:50 AM

ANYONE?? Same issue
Gigabyte P55A-UD3
Lynnfield Quadcore i5
Gigabyte HD 6850 OC
July 17, 2012 8:32:22 AM

I have the same problem.
Motherboard won't POST when all DIMM's are full (Or even just 3). It does POST when one or 2 (Any 2) DIMM's are used. I have replaced the motherboard to no avail. I have also tried different memory, PSU, video card..


Gigabyte GA-x79-UD3
4x4GB RipjawZ
3820 i7 Hex core
F11 bios.