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Computer turns on then off.

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August 22, 2012 4:03:18 AM

Hello guys, I bought a computer for my newphew which is going to be homebuilt because he is a gamer and will get more bang for his buck. I have built my own computer before so I figured I wouldn't run into any issues, but fate has planned otherwise.

Problem:

Got everything built and installed, turn on the power button and noticed that the cpu fan struggled to spin, then started spinning normally, then completely did a full stop.

At first, I thought I had something wrong with my cpu fan, but I hooked it up to my cpu and it spinned perfectly fine. I thought great, thats out of the way.. So what else could it be?

Then I thought it might be the mobo or PSU, but my mobo lights up fine. Then I noticed when I turned on my computer, that my power LED light powers up for about 3 seconds, then shuts down.

As it turns out, I didn't put the stand offs in place as my old rig had them already preinstalled so I didn't think about it. Well I put on the standoffs and thought for sure it would work now.

Well everything pretty much went the same. Power comes on for 3 seconds (via LED light), fan spins, and then it just shuts off.

Does anyone know what could be causing this? I"m suppose to deliever this computer to my newphew Saturday and it would really suck if I told him I don't have a computer for him. I"m thinking its a faulty mobo, but i'm really just not sure.

Things I tried:

Reseting Cmos
Using both fan headers.
Placing down standoffs (stupid to not put them on my part)

I get no beeps, no post sounds.

Also, when putting in the power swtch pins, they are 2 headed pins which don't tell me which is positive or negative. (I"m assuming this doesn't matter?) Which might be the case.

But before I try that, I want your guys thoughts / opinions on the matter.

Thanks.

More about : computer turns

a b B Homebuilt system
a c 174 à CPUs
August 22, 2012 4:38:29 AM

If you didn't install the standoffs before powering on the board its likely that you shorted something out and caused irreparable damage
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August 22, 2012 12:06:02 PM

Any other answers other than that?
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a b B Homebuilt system
a c 174 à CPUs
August 22, 2012 12:07:45 PM

Shawn2516 said:
Any other answers other than that?


I hate to be the bearer of bad news but you would not be the first person to make that mistake. It happens a lot and almost always ends up with a board that needs to be exchanged/RMAed.

You can try testing the PSU (what is the make/model?) but even if something on the motherboard was connected incorrectly it will usually result in POST beep codes. If you don't hear anything at all then my money is on damage.
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August 22, 2012 12:18:25 PM

I have a Corsair TX850W power supply.

If the motherboard is damaged, do I need to send the CPU back as well? I don't want to RMA a motherboard and realize the cpu got some damage as well, but if not, then i'll just keep it safe till then.
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a b B Homebuilt system
a c 174 à CPUs
August 22, 2012 12:32:31 PM

Shawn2516 said:
I have a Corsair TX850W power supply.

If the motherboard is damaged, do I need to send the CPU back as well? I don't want to RMA a motherboard and realize the cpu got some damage as well, but if not, then i'll just keep it safe till then.


That's a very good PSU so the chances of it being faulty are slim at best. Some motherboards have through-contacts for the CPU socket but many don't. If there are through-contacts it's possible that the CPU was damaged, or both the CPU and the motherboard were damaged. If you can, take the CPU out and test it in another computer.
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August 22, 2012 4:49:29 PM

Well the LED lights on the mobo comes on when I turn it on.

How do I know for sure its the mobo and it short circuited?
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a b B Homebuilt system
a c 174 à CPUs
August 22, 2012 11:40:08 PM

It will be difficult to know what was damaged without performing a process of elimination
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August 23, 2012 12:51:36 AM

Just try to breadboard the mobo with ram and cpu + cooler with another psu if you have any.
That'll confirm where the problem is.
Most likely its the psu, unless you've shorted the mobo.
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