[clue-tech] Unexpected Reboots

[Jim Ockers]

Hi everyone,

Someone asked about CPU temperature and fans.  If the CPU fan is
failing the CPU can overheat and cause a reboot.

> Is there a way to get a temperature reading of the CPU?

 Backplane Location 1 30.0 C 
 Backplane Location 2 27.5 C 
 CPU 1 41.0 C
 Motherboard 33.0 C 

The CPU is 10 deg hotter than the rest of the system but that doesn't
seem excessive given it can get up to 70C before the system even warns
that it's getting too hot.

> Now that cpu has been mentioned I recall a couple of cases where a 
> failed cpu fan (or a slow one) caused unexpected reboots. Replacing 
> the fan fix the problem in one case - in another the cpu had 
> scorched the motherboard by the time I figured out the problem and 
> we had to replace everything. 

I hope that's not the problem here but I guess it could be.  The Dell
server fans are pretty robust and they seem to be OK:

 System Fan 1 2370 RPM 
 System Fan 2 2430 RPM 
 System Fan 3 2430 RPM 
 System Fan 4 2520 RPM 

I'm not sure which of those is on the CPU though.  The minimum RPM is
600 and the maximum is 5700.  When you power on the system the BIOS
turns all of the fans on to maximum just for a moment; it sounds like
a jet aircraft.

One other thing it could be is the failed capacitor problem that affects
motherboards made from 1999-2002 I think, according to this thread:

http://groups.google.com/group/comp.os.linux.hardware/browse_thread/thread/ecb6ff3e9024cf50/cda88671451f86c7%23cda88671451f86c7?sa=X&oi=groupsr&start=0&num=3

I am not sure if Dell's server boards used any of the cheap capacitors
that were likely to fail prematurely.  I would hope not given the cost
of the system...

-- 
Jim Ockers, P.Eng. (ockers at ockers.net)
Contact info: please see http://www.ockers.net/
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