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Motherboard Problem

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March 28, 2011 12:09:27 AM

Hi guys,

First of all, I am a brand new builder, and this is my first build. I have spent the entire day trying to find out why my computer won't turn on. Instead, the fans whir for about half a second, then everything turns off. Yes, all cables from the PSU are plugged into the motherboard, both the 24 pin connector and the 8 pin connector. And yes, I have seen that sticky thread about troubleshooting a computer that won't start up, and I have followed their instructions; the computer still didn't work afterwards. Also, I tested the PSU by jumping the green wire to one of the black wires with a paperclip, and the fans inside started whirring - they don't when I connect it to the motherboard and turn it on. It seems like I have exhausted all of my options besides replacing the motherboard. When building, I was not wearing an anti static wristband, but I was making sure to ground myself about once every ten minutes on a doorknob or my computer case. If you guys have any last solutions, it would be great if you can help me out.

By the way, my motherboard is the Gigabyte GA-P67A-UD4-B3.

Thanks in advance

More about : motherboard problem

a c 716 V Motherboard
March 28, 2011 12:35:47 AM

Welcome to Tom's Forum! :) 

I assume that if the GPU has PCIe 4/6/8-pins that they too are connected. If you mis-wired the Front Panel then that too may cause the problem. I assume everything is properly seated.

Next, try 1 stick of RAM in both the 1st and 2nd DIMM slots.

If you used an after market CPU FAN make certain that there's no Metal <-> MOBO contact. Most Mounts are either plastic or have plastic washers.

Shorting, unscrew all of the MOBO and PCIe screws and dangle the MOBO supported by a towel, away from anything conductive and try to start.

Q - What PSU?
Q - What GPU?

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March 28, 2011 12:44:04 AM

thanks for the quick reply! Earlier today, I did try using only 1 stick of RAM in the 1st slot, but the result was the same. However, the CPU fan I am using is the Corsair H50, and the backplate is coming into contact with some metal parts on the back of the motherboard (The backplate is made out of plastic, however).

The PSU I am using is the Coolermaster gx 650w, and the GPU is the msi cyclone gtx 460.
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a c 716 V Motherboard
March 28, 2011 12:54:15 AM

Try the other suggestions above: GPU has PCIe 2X 6-pins, Shorting, unscrew all of the MOBO and PCIe screws.
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March 28, 2011 1:01:54 AM

Don't think it's shorting... Yesterday, I tried laying the motherboard on top of the anti-static packaging that it came with, and assembling from there - same result.

Also, not quite sure what you mean by the GPU and 2x PCIe 6-pins. Sorry for my noobiness.
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a c 716 V Motherboard
March 28, 2011 1:13:53 AM

You said you have a GTX 460, a GTX 460 requires its own power directly from the PSU, in this case two 6-pin PCIe connectors. Otherwise, the PC will not start-up.

These pins need to be connected to the PSU {Power Supply}

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March 28, 2011 1:16:08 AM

Oh, yes. Those are connected. I also tried starting up without a GPU, and guess what? Same result.
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a c 156 V Motherboard
March 28, 2011 1:22:29 AM


Work systematically through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.
The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboardi...

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case once you are finished.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

Silence, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
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a c 716 V Motherboard
March 28, 2011 1:27:02 AM

Is the H50 pump connected to the CPU FAN Header?
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March 28, 2011 1:29:43 AM

Oh, Jaquith, this brings up another point. On my motherboard, the CPU fan header has 4 prongs. However, the H50 pump only has 3 - so I was connecting it to the system fan header. Is this correct?

Also, my motherboard has no LEDs or beeps when I try to start it up.
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a c 716 V Motherboard
March 28, 2011 1:33:51 AM

The MOBO might not start if nothing's connected to the CPU FAN Header.

Assuming it starts now --- Also, in the BIOS you need to set the 'CPU FAN' to run at 100% and if there's an 'Alarm/Warning' if the CPU Fan fails use that setting as well. You want to know if the pump fails.
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March 28, 2011 1:37:32 AM

I was connecting the corsair case fan that comes with the H50 to the CPU fan header, and they seem to match up. Still unable to startup.
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Best solution

a c 716 V Motherboard
March 28, 2011 1:52:29 AM

Swap them around.

Okay, pull everything except:
{absolute minimum}
1 Stick RAM
CPU + H50 {swap leads}
8/24 PSU
--
Yep that means unplug:
HDD/SSD/ODD {DVDs}
Keyboard
Mouse
GPU
USB {incl headers}
Front Panel connectors {all}

Then use a screw driver/paper clip/wire and short the PWR+ & PWR-

What happens?
Share
March 28, 2011 3:03:45 AM

Got it to turn on! Thank you so much! Now what?
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a c 716 V Motherboard
March 28, 2011 2:28:44 PM

Add in order and one at a time:
GPU
HDD/SSD/ODD {DVDs}
Keyboard
Mouse
Front Panel connectors {all}
USB {incl headers}

My assumption something is bad or maybe the headers incorrectly wired.

Let me know & Good Luck!
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March 29, 2011 2:45:01 AM

Best answer selected by legomyeggodamit.
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March 29, 2011 2:45:22 AM

Yep, got everything to work now! I really owe you one. Thanks a ton
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