Power On cpu fan spins for 1 sec then power down

[jake007]

My components arrived yesterday and after I pieced them today, this strange thing happened.

Basically the A8N green LED is on, indicate a supply of power. However when I tried to switch the computer on, the cpu and system fan spins for 1 second then it immediately powerdown. The green LED is still on. The PC will not POST

Meanwhile I don't think there's any grounding issues, I used the stand-ups according to instructions. What else couldve caused this?

Edit:

Athlon 64 2800+ 754pin
Asus K8N
Radeon 9800pro

 

[NuroMancer]

What power supply, brand and wattage.

 

[imported_michealo]

you have a short somehere is my guess

seen this before

 

[jake007]

A short? I don't think that's possible, I've mounted the stand-ups according to all the instruction provided

Anyway this is the case + PSU I'm using
http://www.ebuyer.com/customer/products...cm9kdWN0X292ZXJ2aWV3&product_uid=87441

Cheers for the reply

 

[KGB]

Jake,

Welcome to the Forums! :beer:

Check two things:

1. Make sure your HSF is properly mounted and that you have thermal grease / pad installed correctly.

2. Make sure your CPU fan is plugged into the correct connector on the MB. The BIOS will shut down the system if it doesn't detect a fan on the CPU FAN header.

Let us know.

 

[sivart]

Look in the BIOS to see if there is a control for the CPU fan, my Gigabyte motherboard had this and the fan would spin for a second, the motherboard would realize the chip wasn't hot enough and stop it.

I disabled this feature for my piece of mind, plus my Zalman fan is barely audible anyway

Sorry, once you get it to POST, try looking for this

 

[NuroMancer]

It could still be that your PSU can't handle your system, give a complete list of all component including pci cards, fans etc.

 

[jake007]

It could still be that your PSU can't handle your system, give a complete list of all component including pci cards, fans etc.

The computer only need the MB, CPU, Graphics card and RAM to POST right?

Same problem even when I strip it down all the way to these necessary components.

1. Make sure your HSF is properly mounted and that you have thermal grease / pad installed correctly.

2. Make sure your CPU fan is plugged into the correct connector on the MB. The BIOS will shut down the system if it doesn't detect a fan on the CPU FAN header.

HSF is properly mounted yes. I use the standard one on the retail pack. I tried to mount it both direction. CPU definitely in the right plug

 

[imported_Phil]

Faulty PSU.

 

[montag451]

Make sure you also disconnect the Headers.....

I had a faulty power sw that did the same as you.

Trip the pwr sw connector on the mobo with a screwdriver

 

[jake007]

Trip the pwr sw connector on the mobo with a screwdriver

Sorry I dont understand

 

[montag451]

If you take the power switch wires off the header on the mobo, all you need to do to switch the system on is to make a contact between the two connectors on the mobo.
Take a screwdriver, touch one pin and, making sure it is still touching one pin, touch the other pin.
That is what your power switch does - causes contact between the two

 

[jake007]

I'm quite skeptical about it, you sure I won't be jolted by 350Watts of electricity?

 

[montag451]

no - but i would use an insulated screwdriver anyway.

Then, yes

 

[canadageek]

it doesn't have any dangerous amount of voltage. i have a bare piece of wire that i use to trip the power on when i have a mobo on my work bench

 

[montag451]

Anyway - its the amps that kill yer. [so everyone tells me]

 

[jake007]

I've just tried it and (yes I'm alive!) the same thing happened.

I'm feeling really down now (was expecting to take part in a cs source clan match today T_T)

 

[montag451]

OK - just another troubleshoot measure.....

DISCONNECT everything from the mobo except
cpu+fan
psu
case speaker

Do you get anything now - any beeps?

If not, then you know the problem is with the mobo or cpu or psu

 

[tRiPpiNxSaV]

happened to me a few times...often its a short in the case...

i would just remove everything out of the case and power it up on a cardboard box...
if it powers up, then you know its a short in the case..
if not...then...i would guess its a power supply issue. try a different PSU.
if it still doesnt work...just press and hold onto to the power button for a few seconds.
I remember years ago, i had an asus mobo that only powered up when I press and HELD onto the power button for a few seconds...

just offering my suggestions...GOOD LUCK!

 

[jake007]

If there is a short, what can I do to stop it?

 

[stockjock]

Pull the board out of the case and place it on workbench...connect everything up to it outside the case...except HDDs and FDD and optical drives...fire it up and see if you get a post...if you do, then you had a grounding problem in your case

 

[helpmeout]

Your statement about trying the heatsink both ways is bothering me. Triple check the heatsink and make sure it's installed correctly. If you do have to reinstall the heatsink, make sure you clean both surfaces, and apply new thermal paste. Also make sure the FAN on the heatsink is plugged into the correct connection on the MOBO. I think you have a temp related problem.

 

[jake007]

I tried putting the MB on the outside and changed the PSU. Same problem.
What else is causing this?

 

[JonB]

Long shot, but a long time ago a new motherboard acted this way. I was using a P4 CPU that the Bios didn't recognize. I ultimately fixed it by borrowing an older, slower P4. Booted, update the BIOS, then it recognized my CPU (and is still running today!).

Perhaps your BIOS just needs to be reset? Looking again at your specs, my scenario above isn't very likely.

 

[jake007]

Update:

This is driving me insane!

I RMA'd both the CPU and Motherboard and received the spanking new components today - The same problem occured!

I tested the MB outside of the case on a cardboard box and nothing, no proper bootup

This fricking thing is doing my head in!