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Computer starts for a second then shuts off

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August 10, 2011 3:48:57 AM

I've read a bunch of threads on this problem all day. I'm not sure what else to do at this point.

I just bought a new motherboard and ram because my computer wouldn't start. This new motherboard won't start either. I figured it was the motherboard since all the fans were still spinning at the time. Now I'm not so sure. These are all the things I've tried today.

I made sure the switch on the back of the PSU was on.
I removed the old thermal paste on my CPU and put on a new coat.
I checked to see if the CPU was seated correctly and made sure the heatsink was touching the CPU.
I made sure all the cables/plugs were completely in (and if I was missing anything, I wasn't).
I removed all the parts from my case, put it on cardboard and tested (mobo, psu, cpu, 1 stick ram, and vid card only).
I did the paper clip test on the PSU.
I checked the power switch to make sure it wasn't stuck. I even tested it with a power switch from an old case.
I did the cardboard thing again with my old mobo with the same results.

Is it possible the PSU is damaged even if the paper clip test works? I hope it's not the CPU because I'm really broke right now. I can barely afford a nice PSU. Is there anything else i can do before I go out and get more parts? I would like some opinions before I go out and get something else.

More about : computer starts shuts

August 10, 2011 4:06:12 AM

Quote:
I removed all the parts from my case, put it on cardboard and tested (mobo, psu, cpu, 1 stick ram, and vid card only).


I assumed that it worked fine and booted to bios?


What happens when you turn it on? Does it just start to power up and then 'click' off, if so and your set up worked as per your quote above I would say you have short between your mobo and your case.

Could you be a little more specific, cheers. Also do you have another rig you could use to troubleshoot individual parts on, because this will make it easier to confirm the fault once you have a suspicion.
August 10, 2011 4:17:57 AM

Ninja Pants said:
Quote:
I removed all the parts from my case, put it on cardboard and tested (mobo, psu, cpu, 1 stick ram, and vid card only).


I assumed that it worked fine and booted to bios?


What happens when you turn it on? Does it just start to power up and then 'click' off, if so and your set up worked as per your quote above I would say you have short between your mobo and your case.

Could you be a little more specific, cheers. Also do you have another rig you could use to troubleshoot individual parts on, because this will make it easier to confirm the fault once you have a suspicion.



Sorry, I should have clarified by saying it didn't work. I figured that since the fans were at least spinning on my old mobo that I would see if they did on that one and the same thing happened. It powers on for a second then shuts off on either mobo.

The paperclip test worked on the PSU, but as soon as it's plugged into the mobo it starts for a second then shuts off. All fans begin to spin then stop.

I'm not sure if this will help, but my old mobo was an Asus P5Q Premium. The new one is a Gigabyte P45T-ES3G. The PSU is a FSP Group 700 Watt (not sure if the brand is good, but it was given to me from my brother).
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August 10, 2011 7:43:37 AM

FSP Group actually manufacture the PSU's for names like Antec and OCZ I believe, I don't know anything about the quality of their own branded PSU's sorry.

OK so basics first (assuming you have plugged everything in correctly)
1. Is the power switch on the PSU in the 'I' position not the 'O' position
2. I know you said you checked the power switch on the case but incase you didnt, to rule this out just jumper the 2 points at the mobo (acts as if switch is on). Still nothing?
3. On the 20/24 pin plug short the green wire to one of the black wires, the psu should fire up (paperclip test)
4. Do you at least hear the fan on the PSU start up? No then its probably faulty
5. Get yourself a PSU tester or a multimeter (about $15) and let the troubleshooting begin, check voltages and also a good idea to test cables.

Obviously if you have another power supply try that, if it boots up with that and nothing happens using 1-4 above then its most likely dead.

Note: Shorting any wires to or from the PSU or Motherboard is done at your own risk, make sure your sure you know what your doing first.

[edit]: did you have any load applied when you did the paper clip test? some (maybe most? not sure) PSU's will not start up without sufficient load.
August 10, 2011 1:34:11 PM

Ninja Pants said:
FSP Group actually manufacture the PSU's for names like Antec and OCZ I believe, I don't know anything about the quality of their own branded PSU's sorry.

OK so basics first (assuming you have plugged everything in correctly)
1. Is the power switch on the PSU in the 'I' position not the 'O' position
2. I know you said you checked the power switch on the case but incase you didnt, to rule this out just jumper the 2 points at the mobo (acts as if switch is on). Still nothing?
3. On the 20/24 pin plug short the green wire to one of the black wires, the psu should fire up (paperclip test)
4. Do you at least hear the fan on the PSU start up? No then its probably faulty
5. Get yourself a PSU tester or a multimeter (about $15) and let the troubleshooting begin, check voltages and also a good idea to test cables.

Obviously if you have another power supply try that, if it boots up with that and nothing happens using 1-4 above then its most likely dead.

Note: Shorting any wires to or from the PSU or Motherboard is done at your own risk, make sure your sure you know what your doing first.

[edit]: did you have any load applied when you did the paper clip test? some (maybe most? not sure) PSU's will not start up without sufficient load.


The switch is in the I postion.
I've ran the paper clip test and it has passed that.
The fan on the PSU does start, it powers up the sys fans and cpu fan, but everything will shut off immediately.
As I said I'm pretty damn broke. I would buy a PSU Tester or Multimeter, but I only have enough money for a new PSU (if that's what I need). I know it's only 15 bucks, and usually that would be fine, but I'm really not in a position to spend money right now.

I will try #2 when I have time.

Is it possible that the PSU still works but the wires are damaged? I wish I had an extra PSU laying around, but I don't. I may have to bite the bullet and buy one today. If the problem persists I guess I will just return it.

BTW thanks for the help.
August 10, 2011 8:05:48 PM

OK... so I got the new PSU and it still has the same exact problem. I am so frustrated right now I almost want to break the whole thing. Anybody else have any suggestions? I'm about to flip out. This is basically a new PC at this point. Brand new mobo, ram, and PSU. What could this possibly be?

Can you please explain what you mean in #2?
August 10, 2011 8:36:14 PM

Ok... Here is an update. If I remove the 4 pin CPU power cable all fans spin and it stays powered on. Once I plug that in it does not work. It's the same with either PSU and either mobo. I know my last post was only a little while ago, but I could really use some help!
August 10, 2011 10:48:05 PM

#2 is a simple check to determine if your power switch is faulty. You simply jumper the two leads on the mobo where your power switch would normally connect. But you can ignore that for the moment because thats not your problem (or at least not the main one).

Because the fan on the PSU started up it was probably not a PSU fault, see above. However the first and obvious thing to rule out is a faulty cable, try it with another one or get a multimeter and test for continuity of the wires.

Unlikely to be a mobo issue if you have tried two... however you shoud check the debugging points with a multimeter and reference your mobo instruction book for the indication of a fault (unless you mobo has a nice debugging code display).

The obvious common factor between both set ups (correct me if im wrong) is the CPU and RAM, If your using 4 sticks, or 2 sticks, whatever, try placing just 2 or 1 stick in the appropriate slot and try booting.
The CPU... have you been removing it and replacing it in each mobo each time? the more you move it the more likely you are to damage it. Also have you been reapplying thermal paste each time? I would not recommend moving your CPU unless you have to.

Also if the set up is being run in your case you still couldn't rule out a short.

Debugging is fun hey...
August 11, 2011 1:40:05 AM

Well I'm pretty sure it was the CPU. I RMAed the mobo and will return the PSU on saturday. Luckily a friend of mine was nice enough to order me a mobo + cpu combo from newegg. Hopefully all will be well. And thanks for the help Ninja, you were the only one to give me a hand, it's much appreciated.
August 11, 2011 2:00:46 AM

No problem, best of luck with the build.
!