[chellebell]

Hi
Can anyone help me please?
I have a emachines 420 that has died on me! It was working fine and then suddenly the screen went blank and the light around the power button stayed on. The pc had to be turned off at the mains and never came back on! I did notice that the fans werent runnning as i couldnt hear them. I have had a look at the power supply - bestec atx-250-12e 250w power supply and there was no 5 or 12v coming out it and the fan wasnt running. So i ordered another one. When that one came i connected the mains to it and the fan in that one doesnt run either again no output even if i hold the power button on. Is there someway i can test if the psu is faulty or if something else is causing it not to work. I have tried it powered and disconnected from the computer but dont know if it needs to be turned on some how? I dont know if something could be wrong with something else which is causing the psu to appear faulty?
Thank you
Michelle

[Walchinc]

Check the monitor with another computer. If this works great . Then we know it could be the VGA card chip on the motherboard that has died on you. Not giving any output to the screen.

[Silvereyes]

The symptoms described suggest a problem with the
motherboard power circuits rather than a psu issue.

ATX style psu's have a 'soft' power switch facility which
prevents any output in the absence of the appropriate
signal on the interface.

This means they simply won't work 'out of circuit' or in
the case of a motherboard problem which prevents this
signal being present.

It is possible to overcome this by shorting the correct
pin to gnd but switch mode psu's need a certain minimum
load in order to function correctly and may actually
be dangerous if operated 'out of circuit'.


@Walchinc

Please be careful when giving advice on subjects in which
you have limited experience. Particularly those which have
serious safety considerations such as power supplies.

[chellebell]

Hi, thanks. The monitor is working fine. How would i know if it is the motherboard that is causing the problem? and if it is, is it expensive to fix?

[rendrag]

Motherboards in general are not user-serviceable, and in of themselves are not that expensive, especially the ones eMachines use. You might have to call them and see what brand and model they used in your PC. if it's available in the retail channel, you should be able to replace it without too much hassle.

good luck

This post has been edited by rendrag: 07 June 2007 - 08:03 AM

[chellebell]

Thanks for your help, i will see what i can find out about the motherboard. Is that likely to be the most probable cause?

[IcemanND]

may be the root cause but may have taken other components with it when it died.

[puntoMX]

For 80% sure it´s the mobo;

You can replace the mobo eith a standard S478 one, but this time I would buy one with a IGP/AGP in you can´t find one with PCI-E.

I would go with a ASRock P4VM890 or so, it even has a PCI-E sloth and isn´t that expensive...

If you need some help, ask us .

This post has been edited by puntoMX: 07 June 2007 - 06:17 PM