computer problem

[microcompiter]

I have a biostar mothboard with pentium 4 socket 775,with a 480w 24/4 power supply, but the power supply doesn't work anymore.
I've bought a 20/4 pin 480w power supply, but when I turn the computer on, after 3 seconds it turn off by it self.
When I unplug the 4 pin conector and turn it back on, it stays on, but my monitor doesn't turn on.(nothing come on)
Can some one tell me what i should do, or what is the problem?

Btw the power supply works fine on my other motherboard

 

[Celegorm]

You'll need that four pin to POST video so I'm not suprised it didn't give the monitor signal without it. Depending on your motherboard, you may need to find a PSU with the 24/4 setup.

 

[worshipme]

but when I turn the computer on, after 3 seconds it turn off by it self.

When I unplug the 4 pin conector and turn it back on, it stays on, but my monitor doesn't turn on.(nothing come on)

Sound to me like your CPU is overheating. It shuts down so avoid damage to the processor because of too high temps. The 4 pin connector provides power to the processor so therefore with no power your CPU isn't going to be overheating but your system won't POST, hence the black screen. Check your HSF is secured properly and that the fan is spinning.

My Q6600 did exactly the same thing because of the Intel push pins.

 

[wol-va-rine]

Sound to me like your CPU is overheating. It shuts down so avoid damage to the processor because of too high temps. The 4 pin connector provides power to the processor so therefore with no power your CPU isn't going to be overheating but your system won't POST, hence the black screen. Check your HSF is secured properly and that the fan is spinning.

My Q6600 did exactly the same thing because of the Intel push pins.

this is exactly what I was going to say, also, worshipme didn't mention this, and I'm not trying to insult you, but did you put thermal grease or anything between the heatsink/fan and the processor...? also, I have had problems with the hs&f having to be oriented a certain way on the processor with certain intel stock heatsinks, if it still does it and you're sure it's secure, rotate the hs&f one screw hole to the left or right and see if that helps, it did when I installed my E6600...

 

[ssc456]

i wouldnt say overheating not in 3 seconds, i would sya a motherboard short, possbile take the mobo cpu and ram out of the case and place it on an anti static surface, then use a screw driver to jump the power pins and plug a monitor in see what the results are

 

[worshipme]

i wouldnt say overheating not in 3 seconds, i would sya a motherboard short, possbile take the mobo cpu and ram out of the case and place it on an anti static surface, then use a screw driver to jump the power pins and plug a monitor in see what the results are

If the HSF is not properly secured then overheating can happen that quickly. But what you said is also a possibility. There could be a screw in where it shouldn't be behind the motherboard.

 

[microcompiter]

The computer was a 7 moths old built computer, i did it my self, completly new parts, but yesterday the powersupply made a strange sound ahd the computer turned off, and won't turn on anymore.
I just changed the power supply, but it comes on, zink fan works, but it turn off in 2 to 3 seconds, but when I unplug the 4 pin conector, it works fine, but srceen doesn't come on.

 

[ssc456]

ummmmmm ok you have just told us that now try what we are telling you,

take the heatsink off and reseat it then take your whole comp, motherboard RAM and processor + Heasink and fan, and take the powersupply and place them on a anti static surface, then plug the power supply in and jump the power pins found in your motherboard manual,

 

[Remeniz]

If you just replaced the PSU without removing the Mobo then make sure you haven't dropped a metallic object between the Mobo and Mobo tray, as WorshipMe said earlier.

Having said that, just give what ssc456 has said a go, and if the above has happened you will find out then.

 

[xtremezx2]

If above doesn't work (being he said this computer was running for 7 months before) your board probably took a hit from the power supply when it died. May be time to contact Biostar about a warranty.