Computer turns itself off

[spittingtrashcan]

Hello all,

I've been using my PCC computer for about three months without incident. However, recently the computer developed a most disturbing behavior: it will turn itself off without warning. After it turns off, it cannot be turned on by pressing the power button. It must be unplugged from the wall and plugged back in before it can be turned on. This has happened three times now, with shorter and shorter times between when I turn the computer on and when it turns itself off. The last time I turned my computer on it turned itself off after about ten minutes. Needless to say this makes working with the computer a bit difficult.

I already checked my power cable: it is connected firmly to the back of the computer. I also checked my computer's power settings: it is set never to turn off, hibernate, stand by or anything of that sort.

I have a theory about this behavior. Perhaps an internal sensor has gone miscalibrated and is reporting dangerous temperature, current or the like. To preserve the computer from this perceived threat it shuts the system down. Unplugging the computer resets the sensor and allows the computer to be turned back on, but as the sensor goes increasingly out of alignment it takes less and less to trip it. Does this theory hold any water?

I'd appreciate any help with this problem, as the computer is eminently unusable in this state. Thanks in advance for your assistance.

[Mal Nemesis]

Sounds like your theory could be correct on this one. Does it shutdown as soon as you press the power button or could you get into the BIOS and check the temperature it has listed? If you can, that would explain it a little bit more. Try plugging it into a different outlet too, I have had some similar problems with other components (guitar amp and tv) when I had a faulty surge protector, so the same thing could have happened or it could be a faulty outlet.

[FotoGraffer]

Hey Spit,
I just went thru the same issue myself - turned out to be a faulty power supply - not putting out enough juice. Any way you can measure voltages and amps?

[PCC-Richard]

Send me an email, and we'll get you all resolved.

richard@pugetsystems.com

[spittingtrashcan]

I've been corresponding with Mr. Chau of Puget Computers, which has led to me replacing the psu - and discovering that the psu itself wasn't the problem. The backfacing cooling fan of both psus did not spin, because neither had the fan control wire connected to the motherboard's PSU_FAN socket. The inactive fan caused the psu to overheat, whereupon an internal thermostat shut it down.

Unfortunately, I can't just plug the psu fan control wire in: my system has two backfacing case fans, and they are connected to CHA_FAN and PSU_FAN, leaving no socket free for my psu fan control wire. Has anyone been in a similar situation? Is there some kind of two-to-one splitter wire for these sockets, or is some other solution called for?

[PCC-Jon]

Hmm...are you sure it isn't spinning because that wire isn't plugged in? I always thought that wire was just for monitoring. Try unplugging the fan plugged into the PWR_FAN connector, and plug the power supply into there. If it does spin up, then you're right! There are plenty of adapters that will plug a fan into a full size power connector, and we can always drop one in the mail.

But you said that didn't solve the problem -- have you checked your CPU temperature? My guess is similar to yours, but I think your CPU might really be overheating....it sounds like a slightly unseated CPU heatsink to me.

[TheMattrix]

Yeah, if the yellow fan controller wire isn't plugged in, the fan is supposed to spin at full speed...