FreeBSD 6.1-STABLE: Unexplained power off

[Peter Jeremy]

On Tue, 2006-Aug-15 21:17:21 +0300, Apatewna wrote:
>O/H Android Andrew [:] ??????:
>>I've checked supply voltages by digital multimeter,

This won't show a noisy supply rail (eg due to high ESR capacitors).
If you suspect power, check the rails under load (eg lots of disk
seeks and I/O) using an oscilloscope.

>> and temperature I've 
>>checked "manually" by putting my hand on supply case

Assuming the PSU cooling fan is running, the temperature of the
exhaust air would be more accurate.  (If the cooling fan isn't
running, I'd check why).

>>The same system has been working properly for the last 6 months under 
>>amd64 version of FreeBSD 6.0-STABLE...

Are you in a position to revert and see if the system starts working
stably?

>Check your BIOS to see if it has the option "CPU thermal shutdown".
>I always disable it on client systems since it has the potential of 
>driving you nuts with no apparent reason.

I've had my laptop thermal sensor glitch once but it logged an
overtemperature event before it shutdown.  The downside of inhibiting
the thermal shutdown is that if a real problem eventuates (and CPU
fans do fail), you will destroy the CPU and maybe mobo.

It might be worthwhile setting up a serial console and logging it
on another box to see if anything is written to the console before
it dies.

-- 
Peter Jeremy
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