FreeBSD 6.1-STABLE: Unexplained power off

Michael Proto mike at
Tue Aug 15 20:05:18 UTC 2006

Android Andrew [:] wrote:
> Peter Jeremy wrote:
>> 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.
> I've checked voltages on MB contacts exactly under load (during port
> compilation). I have no oscilloscope, so I can't control voltage
> impulse, especially on multiple channels.
> In this case I could only replace PSU for testing.

I would recommend this based on my own personal experience. PSUs are the
 single most-replaced component in both my desktops and servers
(white-box servers anyway), and I've spent countless hours trying to
track down similar issues only to have the problem disappear when the
power supply was replaced. I keep a collection of various spare PSUs at
my site just for this purpose, as its often not a case of IF a power
supply will start going out, but WHEN.

Your mileage may vary of course, but if it were me I'd try replacing the
PSU first and see if the situation improves.


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