OT: system shuts off sporadically

[Vaughn Treude]

On Mon, 2006-01-16 at 12:38, Craig White wrote:
> On Mon, 2006-01-16 at 12:35 -0700, Vaughn Treude wrote:
> > Hello everyone:
> > I've been experiencing a problem with one of my PC's.  Eight months ago
> > I upgraded it to an Abit VIA KM400A motherboard with an AMD processor
> > and new RAM.  In the last couple of weeks it's started shutting itself
> > off sporadically, for no apparent or consistent reason.  I know it's not
> > a software problem (though if anyone wonders, I've got Ubuntu on it, and
> > have been quite happy with that flavor of Linux) because it has at times
> > shut itself off while I'm in the BIOS setup screen.  I have replaced the
> > power supply and that didn't help.  I suppose it's probably a
> > motherboard problem, and I believe it's still under warranty, BUT
> > sending it back will be a hassle and I'll lose the use of that machine
> > for a few weeks at least. Most odiously, I'll have to reinstall the
> > processor and mess with that heat sink junk once again. So I'm wondering
> > if anybody knows of anything else that could cause this problem.
> > 
> > Some more info:
> > - The problem appears to be totally random, sometimes happening within a
> > minute of startup, sometimes hours later.
> > - Sometimes the system will not restart for a few minutes after this
> > happens.  Or sometimes it will start but not boot.
> > - Often when this happens the BIOS checksum gets corrupted and I have to
> > re-enter my settings.
> > - In BIOS, I've taken care to turn off features I'm not using, such as
> > APIC and SATA support. I've turned off power management to the extent
> > the BIOS allowed me to do that. I've also set the power-off switch mode
> > to a 4 second delay, in case there could be noise spikes on the power
> > switch line.  I've turned off the "halt on errors" feature.
> > - In the BIOS PC health screen the CPU temperature appears to be well
> > within the good range.  However, I've only checked this shortly after
> > power-on.
> > - The motherboard is rather compact, and is mounted in a maxi-tower case
> > with extra fans.  I don't know for a fact if the airflow is optimal.
> > - I've checked the system logs and there is absolutely no record of any
> > kind of error at the time it powers itself off.
> > 
> > Any ideas of what I might try, or any resources I could use?  I googled
> > for it under "PC sporadic shut off" but didn't get any useful hits. 
> > Half of the problem with googling for a PC problem is knowing what to
> > call it!
> > 
> > Thanks in advance for any suggestions you might have,
> ----
> I have had that happen from 3 different causes that I can recall.
> 
> The first was a failing power supply which apparently you have already
> replaced.
> 
> The second was with a bad cpu fan where the temperature of the cpu would
> cause it to shut down. You should be able to monitor the temperatures
> but acpi would have to be turned on and with Linux, you would probably
> have to install and configure lmsensors and probably something like
> gkrellm.
> 
> The third was most recently when a Dell system had capacitors that were
> leaking - you could see the gook on the top of the capacitors when you
> looked at the motherboard. This is most likely the issue and I would
> recommend that you look carefully at the capacitors on the motherboard
> and if there is anything other than dust on the top of some of them,
> replace the motherboard as there is no other option.
> 
> Also - as a method of control, if the computer is plugged in to a wall
> outlet, I would plug a plug strip into the wall outlet and plug the
> computer into the strip along with something else that would turn off
> (but not back on) if for some reason the power dropped momentarily.
> 
> Craig
> 

Thanks for the ideas, Craig, Miles, Austin, and Cat.  I think the CPU
fan is OK, and the CPU temperature was good at least when I first
powered it up.  Unless the fan is randomly stalling out, I doubt it's
heat related, since the timing is so sporadic.  (Then again, the fact
that it sometimes won't come up for a couple of minutes does make it
seem heat-related.)  So far it's been up and running for 2 hrs now.  The
next time it shuts itself off I'll open it again and look at the caps. 
I didn't notice any capacitor gook when I had it open earlier but I
wasn't looking for that either.  :-)  If all else fails, I'll send it
back for warranty service.

Vaughn


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