# [SOLVED] Motherboard Short



## Doc11354 (Apr 19, 2011)

I need to know if I have shorted out my new motherboard. I am assembling a machine using a MSI P35 Neo motherboard with an Intel P4 2.8 Ghz. I am putting it in a cheapie case with a Power Rebel model # RB-ATX 400A power supply. I had the machine running but the CPU temp was running at 64C in Idle, so I took off the fan and reinstalled Artic silver 5 paste. I reinstalled the fan and checked that everything was connected properly, it was. The problem started when I booted the system. The system would start to boot and within 5 seconds it would shut down. I thought O.K. either the paste isn't applied correctly or the fan isn't seated properly, so I removed the fan again and removed the processor. I cleaned both with Isoprophyl alchol, and reinstalled the paste according to Artic silvers web site. After assembling everything again, the machine still booted and shut down after 5 seconds. I had a brain fart and decided to unplug everything from the case. I unplugged everything except the 24 pin power connection and the 24 volt cpu connection. I turned on the computer and it tried to boot, but shut down again after 5 seconds. The strange part is, I had ALL the case wires unplugged from the motherboard, No Power connection, no HD light, no reset switch. no power lights, and the computer tried to boot. Have I shorted the power connection on the motherboard? I do NOT have to short the power pins on the motherboard to start the machine. Please help


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## MPR (Aug 28, 2010)

*Re: Motherboard Short*

Rapid shutdowns can occur if the CPU fan is unplugged or if the motherboard circuitry doesn't detect that the CPU fan is spinning up properly. Also, there is a possibility that something underneath the motherboard is causing a short. I had a system once that was doing all sorts of weird things until I removed the motherboard and found a lose screw underneath it. Another possibility is that your PSU is the culprit. Have you removed the motherboard from the case and tested your system as per the instructions here?


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## Tyree (May 10, 2009)

*Re: Motherboard Short*

Brand & Model of Mobo-CPU-Hdd-RAM-GPU-.
The PSU you have is a very poor quality piece of junk. 
Do a bench test with a good quality PSU.
If all is well, assemble in the case using one standoff, no ore-no less, for each mounting hole in the Mobo.
Remove EVERYTHING from the case
Set the motherboard on a non conductive surface. The motherboard box is perfect for this. DO NOT PLACE THE MOTHERBOARD ON THE STATIC BAG! It can actually conduct electricity! We are going to try and assemble a running system outside of the case.
Install the CPU and heat sink. 
Install 1 stick of RAM.
Install the video card and attach the power supply connection(s) to the card if your card needs it.
Connect the monitor to the video card.
Connect the power supply to the motherboard with both the 24pin main ATX Power connection and the separate 4 or 8 pin power connection.
Connect power to the power supply.
Do NOT connect ANYTHING else. Make sure you have the power connector on the CPU fan connected.
Use a small screwdriver to momentarily short the power switch connector on the motherboard. Consult your motherboard manual to find which two pins connect to your case's power switch. Then touch both pins with a screwdriver to complete the circuit and boot the system.

If all is well, it should power up and you should get a display. Then assemble the parts into the case and try again. If the system now fails to boot, you have a short in the case and need to recheck your motherboard standoffs.

If the system does not boot after this process, then you most likely have a faulty component. You'll need to swap parts, start with the power supply, until you determine what is defective.


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## Doc11354 (Apr 19, 2011)

*Re: Motherboard Short*

Thank You for the reply. Please consider that I have built systems since 1989 and know that the power supply is not of good quality, but it was operating the system. This system was running before I reapplied the thermal paste. Also I do not have to short the pins on the motherboard for the computer to boot. Therein lies the problem. I have assembled the system outside of the case as per instructions, and it tries to boot without shorting the pins. What could be causing the motherboard to try to boot without having to use the screwdriver to short the pins?


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## Tyree (May 10, 2009)

*Re: Motherboard Short*

Have you tried the bench test using a good quality PSU?
Using that PSU may have done some damage.
It is not uncommon for the system to boot when the power cord is connected without shorting pins if the system was shut down by unplugging the power cord.


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## Doc11354 (Apr 19, 2011)

*Re: Motherboard Short*

I did try an Antec power supply on the bench, but it was only a 350 watt. It also only has the 20 pin connector not the 24 pin. I thought this might work as I only had the cpu, the cpufan, 1 stick of memory and a Radeon HD 4350 video card only on the motherboard. It is still doing the same thing with this PS. It looks like I will need to borrow or purchase a new PS before I can tell if the motherboard is actually bad. By the way I have purchased, and being shipped, a C2D processor to install on this motherboard, so I want to be sure the board is O.K. before ruining the C2D processor. Is there anything else I should try?


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## Tyree (May 10, 2009)

*Re: Motherboard Short*

If no joy after doing the bench test properly with a good quality PSU, refer to the last paragraph of the bench test.

If the system does not boot after this process, then you most likely have a faulty component. You'll need to swap parts, start with the power supply, until you determine what is defective.


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## pwang (Oct 27, 2015)

You can try to reset bios. If it continues to shutdown after a couple of seconds or turns itself on without shorting poweron pin to ground something might have shorted in the board during component removal with power still connected to the board. There is a live 5volts standby all the times as long as the power connector from psu which is still plugged into ac source.


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