PC turns off after 1 second

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Ruraji

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Hello


I have recently built a new PC but it is giving me some problems. First the problem was that it wouldn't POST, though it did seem to be getting power(fans running). So after much research and discussion on the matter I decided that the most likely culprit was the motherboard. So I returned the motherboard, buying a new one afterwards from a different shop. Now things have changed slightly. When I turn on my computer the fans run for one second and then they power off. I bought a multimeter and tested the PSU and it does seem to be ok. I have unplugged the graphics card and ram so they're not the problem. Maybe the CPU somehow? I really don't know. I am testing it on cardboard by the way.

My Specs:

Motherboard: MSI P7N Platinum
Power Supply: Corsair 650
CPU: Pentium D(dual core) E2180
Case: Cooler Master Elite

The rest is unplugged.
 

auscanzukus

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I suspect 2 things: bios & ram.

If the bios doesn't support the cpu, the pc won't post.

If it's the ram, try each stick in each slot and set up ram in bios upon post.

Have you cleared cmos?
 

peter_peter

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Boot you pc with minimum: CPU, Video Card, one stick of RAM. Can you view your bios? Make sure you are using the correct secondary power connection to your board. (4, 6 or 8, it does matter). Also check that cup fan, connected to correct connection?
 

Ruraji

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Thanks for the replies. The heatsink is plugged in correctly. I don't think the ram is the problem as I don't have any plugged in, I should get beeps right? Also all my items are compatible.
 

atrain

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Nice alliteration :D

Definitely sounds like a mobo problem to me.
 

peter_peter

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lol, You obviously know I didn’t major in English.

What I meant was to check the CPU Fan power connector - if plugged to the wrong power connector, the board may not read the heatsink fan and may not boot.

Please check my spelling, lol
 

atrain

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Not to be the grammar nazi of THF :kaola:, but alliteration is the use of similar sounding consonants at the beginning of 3 or more words. I wasn't correcting your English, rather commending it(even if you didn't know you did it :lol: )
 
I know a builder that once got an entire shipment of bad boards from a major MB manufacturer. 5 or 6 as i recall. All genuinely bad. If your board is supposed to beep and does not, I only know of three posibilities:

a. Bad board

b. You plugged something into it wrong, or dropped a screw onto it and left it there, or it's making contact somewhere it should not.

c. Bad PSU
 

Ruraji

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Well it shouldn't be "a." as I explained before. Nor should it be "b." as I put the motherboard straight on a piece of cardboard. It could be "c." but the multimeter says that it is working.
 
I'm not an electrical engineer but I don't think a multi-meter is a good test for a PSU, because it doesn't put a load on the line.

Did you know that your PSU emits a "ready" signal once it has warmed up? This is to signal the motherboard that it can safely draw power. Usually takes under a second for this signal to be sent.

The other thing your PSU can do is automatically shut down if there is a draw on it's power that exceeds it's rating.... provided that sensor is working properly.

My point is that your PSU does more than just supply a set voltage, and there is more that can go wrong.

 

peter_peter

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Raruji, can you even get to your BIOS?
If not - did you do the minimum requirement as they asked above?
You mentioned you don't have RAM? You need to get a stick in there, at least one stick. I've had several times where the RAM stick is bad. Also, are you using a 4pin CPU power connector or 8 pin power connector? Your not using PCI one right? or 6 Pin right? I had a friend do that and would not boot. Also, you video card, installed in the correct slot?
 

radnor

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PC turning up for 1 second means you got a short circuit in there or a Open Circuit (don't know the English translation, it is like a loop getting feeded) and the PSU or Mobo protects itself and the rest of the hardware.

It can be:

- Burned CPU (when a PC does POST, it is the first thing he will check)
- Bad PSU (Most likely)
- Bad Mobo (Not likely)

Can be anything with a 12v+5v plugged in. Even a DVD-RW can do it. Want a sound advice? Strip it down. Leave just Mobo&PSU.
If they turn on and keep turned on, insert the CPU&HSF.
If they turn on and keep turned on, insert the GPU.
If they turn on and keep turned on, insert the HDD.
...
...
If it stop turning on when you put a piece, you got there your bad piece.

And so forth. Welcome to Diagnosing a facked up PC 101 by Radnor Harkönnen.
 

Ruraji

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I removed the CPU so it's only the Mobo and PSU. I'm still getting the same problem. I guess it is most likely the PSU then. God I hope they don't make me pay the postage when I exchange it. ><
 

lelizondob

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I know the last reply it's old but here's what happened to me and what I did.

I run a dual boot with 2 hd, in one I have Vista and in the other one I run Ubuntu. I was reinstalling vista because of a virus but I just couldn't, I figured out that was because of my second hd so I removed the power from that hd. I could install after that just to find out that vista installer freezes after the first restart.

In the process, I must had moved something in the motherboard because my pc wasn't booting at all. All I've got was the fans running, 10 seconds after 1 beep and then the fans turned off.

I knew it wasn't a motherboard or a power problem, so I learned the following:

1. The pc won't boot if the processor fan it's not correctly attached and secured. For some reason.
2. I removed and reinstalled the memory.
3. Did a lot of clean up, no dust at all.
4. Removed every card, video card, tv turner card, wireless card, etc.
5. Just plugged in, memory, dvd and hd.

Booted and everything it's working.

I'm installing vista as I'm writing here but I hope I won't be having any problems. I'm guessing that vista was freezing because of the video card, maybe it wasn't a very good idea to install vista using my nvidia card, I'll just install it after vista do it's thing.
 
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