System starts then shuts down seconds later.

[grindy]

Hi,

My second system is a P4 desktop. It was working fine, no symptoms of any problems - then yesturday it would start briefly and then completly shut down after about 5 seconds. No POST beeps at all, just shuts itself down.


Here's what I've done:


Switched the PSU with a known good one, same problem.

Removed video card and all RAM, unpluged power from all drives - same problem.


Is there anything besides an overheating CPU that can cause this? Both fans spinup at startup without problem.


All ideas welcome.

 

[Slaymate]

If the power switch is shorted or stuck it will power off.

 

[VsUK81]

Hmm i had a problem like this once on 2 machines. The first machine PSU wasnt providing enough power & just cut out as soon as everything started to power up. The Second was a faulty PSU to Motherboard connection.

So have you tried any or all of these.

1) Replace PSU
2) Replace GPU
3) Change or swop memory slots
4) Remove all power connectors to none critical hardware needed to boot up
5) Checked to cpu for over heating
6) Replaced the Thermal Compound on the cpu with a fresh batch
7) Make sure there's no phisical connection from your motherboard to the case (I had a screw under mine once, fractions away from blowing my board completely)

If you have done all these & it still boots up & then shuts off after 5 seconds, i can only think a motherboard problem.

When you boot up, does anything show on the screen before it turns off or does it trigger your monitor to fire up or dosnt it get that far?

If the power switch is shorted or stuck it will power off.

You can test this by un plugging the lead to your pw sw lead from your mobo & put your reset sw lead in staid & push it in to power it up.

 

[v8killaz]

cpu
motherboard