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Frequent shutdowns, I7-950, where to start?

Posted: Fri May 13, 2011 5:55 am
by Bookseller
I have an Intel DX58S0 and i7-950, NOT overclocked, built about 18 months ago and has been rock solid.

The last two boots after it was off and cold it has reset itself every few minutes. It runs for a while (increasingly longer each time), then reboots.

There are no hardware errors in the bios, there are no event log entries of interest (other than the "was unexpected"), there are no overt symptoms on the screen, and no beeps or unusual noises. I ran the CPUID Hardware monitor once and as it reset temperatures were cool and normal (mid 50's c). It is literally as though the reset button was hit.

I have opened it up and while running shaken and pulled every connector and card without impact. I have booted windows (7 x 64) into safe mode and it still fails (plus there are no signs of a blue screen or exception logged). Last time, once it was up and seemed stable, I ran about 12 hours of memory tests without error (not that I specifically suspected memory but figured that was a good mid-level load).

Last time after finally staying up, it stayed up for about two weeks without problems (I usually leave it up except when travelling). This time am on about the 8th boot, not sure if it will stay up.

I've watched the case when it reboots (a bit hard to catch in the act as there is no warning), and I did not notice any flicker in the lights on the fans, just the fan speeded up as it does when it first boots. I cannot swear I would have seen a brief flicker as you have to stare anywhere up to about an hour and I don't quite have that attention span.

WIth no symptoms other than a reboot -- not sure where to start. Any recommendations? I'm thinking power supply, but I do not have a good spare (I have one, but it is an old 400W and not sure that is adequate but may try it anyway, it is close). Currently trying it off the UPS, but not hopeful there, no reason to suspect it.

Re: Frequent shutdowns, I7-950, where to start?

Posted: Fri May 13, 2011 6:35 am
by bubba
could be the UPS or the power supply. Pull it off the UPS and run it, if it still messes up try the spare power supply.

If it still messes up, could be a short in one of the case switches. pull the switch wires off the motherboard (remember which is the power) use a small flat head screw driver to short between the two posts for the power switch on the motherboard, just touch it for a split second. That simulates the momentary switch on the case. If you have no issues then, its the case switch.

Re: Frequent shutdowns, I7-950, where to start?

Posted: Fri May 13, 2011 8:32 am
by Bookseller
Well, much to my surprise, it has been running now about 3 hours on utility power not UPS.

Going to move it back and see if it fails again.

And it's a pretty nice UPS, not one of the cheap ones (APC RS 1500).

Re: Frequent shutdowns, I7-950, where to start?

Posted: Mon May 16, 2011 8:56 am
by Bookseller
So much for that theory, it shut down twice this morning (after running for 2 days), once on the UPS, once off the UPS.

I swapped out the 850w power supply for a (gulp) 400w that I had in an old PC. With 4 hungry drives was a bit worried that at power up I may lose it. It came up, voltages look normal, and it has been running a couple hours. Only have today before I leave town again, but going to try this again when I return and if no crashes will get a new power supply.

Starting to lean toward the power supply (a nice fancy Corsair too!).

PS. I have not actually disconnected the reset button yet, that's also on the list, but I did shake, push, pull, twist and otherwise try to make them fail without success. Just didn't have the manual handy to know which wires to pull.

Re: Frequent shutdowns, I7-950, where to start?

Posted: Sat May 28, 2011 4:54 pm
by Bookseller
Definitely power supply, a new one solved all problems. Other going back to Corsair.