Pc runs or 3 seconds then powers off

Can you help?
I have just put a second PC together and at switch on in runs for 3 or 4 seconds then powers off. i have tried 2 PSU's and the case switch was working fine last time it was used. I have removed the sound card and it makes no diff. Asus A7N8delus Sempron 2500 256 PC3200 Ram.What may be the problem. I am getting no bleeps. Just 3 or 4 seconds of fan action then nothing.
OldwaspAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

gjohnson99Commented:
What do you mean runs? bootup or the fan just run.

If the fan just run it is most likely that the 12 volt power to cpu are missing.
0
OldwaspAuthor Commented:
It runs as you would expect but just as you would expect the POST beeps it powers off. The mobo power plug is in and it is AMD so no separate P4 plug needed. The fans take power from the mobo.
0
Chris BRetiredCommented:
If the P4 socket exists on the mobo, and the plug is not in, the CPU is not firing.

Chris B
0
Ultimate Tool Kit for Technology Solution Provider

Broken down into practical pointers and step-by-step instructions, the IT Service Excellence Tool Kit delivers expert advice for technology solution providers. Get your free copy now.

gjohnson99Commented:
Do you have the right power supply for the AMD mb.

Dose the connector fill the slot it is in ?

Is power supply 350 watt or bigger ?

If your power supply is for a PIII it won't work !
0
Chris BRetiredCommented:
Had a look at the picture - no socket, so that isn't the problem. Have you got the CPU fan plugged into the correct socket. If it is in a chassis fan socket, the CPU won't start - to protect against overheat.

Chris B
0
gjohnson99Commented:
AMD mothbraods don't  use 4 pin conecter like Intel.

They have 24 pin connector insted of 20 pin connector.

High end Intel stuff also uses the newer pin layout.

But on an AMD mb if you only have a 20 pin connector it wont work!
0
Chris BRetiredCommented:
<<AMD mothbraods don't  use 4 pin conecter like Intel.>> Not necessarily - many do use the 4 pin system eg, most Shuttle, some Soltek, some Asus etc. However, as gjohnson99 indicates, the configuration must match - in this case if your psu has the 4 pin plug, it won't work with your board. Curious though, can you get the 20 pin plug into the 24 pin socket? I wouldn't have thought so.

Chris B
0
gjohnson99Commented:
burrcm

you can fit the 20 pin plug  in the 24 pin socket  but  won't get 12 volt for the cpu.
0
Chris BRetiredCommented:
So Oldwasp, is there a gap at the end of your power connector??

Chris B
0
xtremecrisCommented:
Maybe the CPU overheats. Have you applyed thermal paste or thermal pad between CPU and Cooler?

I had a similar problem with my Abit NF7 2.0. The only difference is that after it turned off the power it would make a siren sound in the pc-speaker.

P.S.: The same mobo started with a 235W power supply, and my CPU had only 1,1Ghz instead of it's regular 1,83Ghz(Barton 2500+).
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
nobusCommented:
disconnect or remove every device possible,and start with only 1ram stick, kdb+mouse,video 1hdd.
if you do not get a post screen, i would think : bad ram, bad motherboard, or bad CPU (least likely)
As it are new parts, return them and have a warranty replacement
You can also check if the ram is compatible with your motherboard at www.crucial.com or www.kingston.com
0
OldwaspAuthor Commented:
I was going to try another cpu but on removing the old one I found the pre applied paste was not disturbed on the bottom of the heat sink dispite being seated fully. I spun 180 dreggrees and seated again and this time no problem. Many thanks.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Desktops

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.