Newbe - Power only last about 2 sec

[jbrd10001]

When I turn my computer on power only lasts 3 secs and shuts down. My flat monitor says no signal. Where do I start - with the video cards or resetting the motherboard -- or something else?

[pt]

Wich are your system specs?

[newmodder]

i would make sure your vid card is seated properly to start

[Frogger]

can the rig get past the post if not you prob have a power supply problem

[JC316]

can the rig get past the post if not you prob have a power supply problem

Not necessarily, when I hooked up two molex connectors to my defective X1800XL, my system would barely power up and then it would die.

[GLD]

Is your cpu heatsink seated correctly? If it is not that can trigger a motherboard to shut down right away, to prevent a cpu bbq.

[DanTheBanjoman]

Usually monitors only say "no signal" when they're not connected to a videocard. Even when the computer is turned off it apparantly gives some sort of a signal. So a videocard problem might be the problem, otherwise perhaps the motherboard which fails to power the videocard. I would suggest trying another videocard if you have one.

[bbriand]

Do you have any custom solder jobs or connections which might be shorting out the PSU? Sounds like the PSU might be tripping some sort of overload or something. Do the fans work on the PSU when you turn the power on to your system? Maybe you have too many perpherials for the PSU to handle?

Could your Heatsink on your CPU not be seated properly? I don't know how long it would take one to overheat and shut down a system (2 seconds seems kinda short for this but I honestly don't know).

Bill

[{JNT}Raptor]

When I turn my computer on power only lasts 3 secs and shuts down. My flat monitor says no signal. Where do I start - with the video cards or resetting the motherboard -- or something else?

Thats usually a grounding Issue...meaning something Is shorting the Mobo with the Case.

Start out with reseating the Mobo......see If one of your Standoffs are off center and shorting the mobo to the case.

Hope It helps. :)

[W1zzard]

take everything out of the case, connect the psu to the motherboard, no need to instlal memory or cpu .. does it power on now?
if it does add components one by one, add cpu at last to save you the work from installing a cpu cooler in that setup .. just check if the system keeps running longer .. if it does install cpu+cooler see if it boots up .. if that works you must have a short circuit somewhere between case and psu

[bbriand]

You might eventually fry something if you look for a short by supplying power to something that is shorted (this is provided that there is a short). I would visually inspect things for shorts first.

You might also try unplugging everything off the PSU (including the mobo power) and fill one rail at a time with fans and power on the PSU. Remove the AC power line from the PSU and everything else connected to it and test if the PSU has an internal short (by testing the positive/negative on each rail).

Then I would personally grab a multimeter and test for a short without any power first. I can't say exactly how, cause I don't have my system in front of me plus this has never happened to me. But here are some things I would try:
1. find out the mobos positive/negative power inputs and check for a short there.
2. check each power connector on the mobo for a short (eg fan connectors).
3. check each power connector of the devices on my system for a short.

All things considered I would test the PSU by itself first. Something might have failed inside of it.

Good luck,
Bill

P.S. something I have never seen with a computer switch, but I have seen on automobiles, are Relays failing. Its my understanding that a comps power switch is a relay... possibly a faulty Power Switch?? Just tossing that out there.