Suspect motherboard

  Ollyolly 12:01 29 Sep 2006

e Machines 420.
Switch on the mains
1. The psu hums but fan doesn't spin.
2. Light on power switch in front of case is illuminated.
3. Press switch on front of case and nothing happens.
4. Fan on CPU doesn't spin.

Do I assume the motherboard has had it?

  Trackrat 12:30 29 Sep 2006

The first thing you need to do is check out the power supply unit, if that is ok, then strip it back to basics ( motherboard/CPU & fan/memory & graphics card, or integrated graphics ) and see if it will boot.
If it does then add the other components back one at a time to see what causes the problem.

  Diemmess 12:43 29 Sep 2006

The PSU statistically is much more likely to fail than the motherboard, but substitution is really the only way to check its health!

To add a gloomy note, very occasionally a PSU failure will cause mischief among the rest of hardware as well!

  woodchip 13:04 29 Sep 2006

Yep PSU Does it give out one beep when it starts? did it used to?

  Ollyolly 13:08 29 Sep 2006

No sounds from the PSU or case speaker.
I'll take it apart tonight and have a play around. Try a currently working PSU and the like.
Thanks for your replies, I'll keep to in touch.

  Fruit Bat /\0/\ 14:37 29 Sep 2006

e Machines PSUs' are notoriously unreliable so would suspect PSU before motherboard.

click here
click here

If renewing a PSU check:

1. The physical size of your PSU, some are hard to replace due to being a non standard size.
2. The amount of power need from the PSU don't skimp

1. Physical Dimensions

Besides the specs and form factors, the physical dimensions are also important factors in selecting a compatible power supply. Here is an outline of the physical dimensions of most standard power supplies:

# ATX: 6x3.5x5.5", HxWxD. Most common. Uses 4 mounting screws.
# Mini-ATX: 5x3.5x5", HxWxD. Rare size. Uses 4 mounting screws. Can be used in a regular ATX case, but often not the other way around.
# MicroATX: 5x3x4", HxWxD. Use 3 mounting screws. Not interchangeable with ATX or miniATX.
# Flex ATX: Even smaller than Micro ATX. Various sizes according to case specs; often not interchangeable.

Use the data above to determine if a particular power supply would fit your case.

The quality of a power supply can be estimated by its weight. While this is not a true scientific or thorough measurement of the power supply reliability, it is nevertheless a very simple and easy way for ordinary PC users to estimate and compare the quality of a power supply.

2. Power supply calculator click here

Guide to changing PSU
click here
click here

  Ollyolly 21:08 29 Sep 2006

Just had the motherboard on the bench connected to a PSU that I took out of a working PC.
With RAM in place or not (and nothing else) the same result - nothing. No lights, no buzzes, no beeps and no fan movement.

The PC came to me in the dead state. I've never heard it make a beep I'm afraid.

While the motherboard was on the bench and everything else still connected in the case I applied 240v to the PSU and shorted pins 14 & 15 as described in the link you provided.
The PSU fan spun and the HDD tried to start. At that point I removed my wire between pins 14 & 15.
From that I'm guessing the PSU is OK.

To sumerise.
Nothing from motherboard when power supplied by working PSU.
PSU fan spins, HDD tries to start when power applied and pins 14 & 15 shorted.

So I think I'm still at the point of suspecting the motherboard. Model Imperial_gv 20030812.

Thanks for your thoughts folks

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