Computer shuts down after a few seconds

[Dogsbody]

Already tried a PSU, no help. I'm going to try setting it up outside the case so I can see if it's shorting out. Never seen anything like this one!

 

[Dogsbody]

Well, this is embarassing. It turned out to be the power switch after all. I thought I had taken it out of the system, but obviously not. Thanks to everyone for the help.

 

[mfenn]

That is a P3 running Q3 though. Sitting idle in BIOS with modern power saving features (reduced core voltage/reduced multiplier - though are they active in bios?? who knows, but regardless) isn't going to overheat your CPU that quickly.


I'm going with dead motherboard or PSU. It is also possible that the MB is shorting out. I'd RMA the MB and hope for the best, but before I sent it, I'd try the build on a cardboard box.

Your first paragraph is absolute bunk. The point of me posting that video was that a CPU can and will fail VERY quickly without proper cooling.

1. Power-saving features are not enabled during POST
2. A CPU has very little thermal mass
3. Modern CPUs will shut down long before they reach the point of critical failure
4. Ergo, the CPU detects thermal runaway, and powers off, even though the max temp that can be sustained for short periods of time has not yet been exceeded.

OP has already replaced the PSU. I'm not discounting the chance the mobo could be borked. BUT, the OP has indicated that the HSF has never been properly mounted. Are you suggesting that he RMA the board before he properly mounts the HSF? If so, you're making a ridiculous assertion.

EDIT: Glad you figured it out OP. However, while you've got it out of the case, you might as well check that the pushpins are properly seated. Props to everyone who suggested the power button.

 

[Absolution75]

Your first paragraph is absolute bunk. The point of me posting that video was that a CPU can and will fail VERY quickly without proper cooling.

1. Power-saving features are not enabled during POST
2. A CPU has very little thermal mass
3. Modern CPUs will shut down long before they reach the point of critical failure
4. Ergo, the CPU detects thermal runaway, and powers off, even though the max temp that can be sustained for short periods of time has not yet been exceeded.

OP has already replaced the PSU. I'm not discounting the chance the mobo could be borked. BUT, the OP has indicated that the HSF has never been properly mounted. Are you suggesting that he RMA the board before he properly mounts the HSF? If so, you're making a ridiculous assertion.

EDIT: Glad you figured it out OP. However, while you've got it out of the case, you might as well check that the pushpins are properly seated. Props to everyone who suggested the power button.

Yeah, I agree with what you said, but the OP said after two or three seconds it would shut down.

In the video you posted, it takes two or three seconds for the CPU to reach throttling temps under what could be considered a heavy load.

The fact that it didn't even post makes it inconsistent to that of an overheating CPU. Also, I've had a friend who's run his Q6600 with only 3/4 push pins connected - and very loosely at that, it ran up to 96C until I fixed it for him. It at least posted. Even with virtually no contact with a heatsink it at least ran.

 

[mfenn]

Yeah, I agree with what you said, but the OP said after two or three seconds it would shut down.

In the video you posted, it takes two or three seconds for the CPU to reach throttling temps under what could be considered a heavy load.

The fact that it didn't even post makes it inconsistent to that of an overheating CPU. Also, I've had a friend who's run his Q6600 with only 3/4 push pins connected - and very loosely at that, it ran up to 96C until I fixed it for him. It at least posted. Even with virtually no contact with a heatsink it at least ran.

Yep, you are right. My bad.