[GTALUG] mysterious restarts

[Russell Reiter]

I thought I would attempt to return to the topic. Although this thread has
been interesting I would like to return to the power supply hypothesis.

> Any suggestions?
>
> It looks as if the power dips momentarily and the computer reboots,

>From the specs it looks like the unit should be able to absorb a certain
amount of voltage sag.

> The crash seems to be at different points (i.e. not one consistent

Could the outlet the unit is plugged into share the neutral bus with a
fridge or furnace motor?

If the fridge or furnace is on the same power leg, on the spiking front,
something ultra-sensitive or approaching EOL is more likely to act up.

> software activity).  The crashes don't seem correlated with heavy
> workloads (eg. it crashed a couple of times while I was staring at log
> files to see if there was any hint of the problem).
>
> Hypothesis: it might be the power supply.  Normally, I'd swap power
> supplies to test this hypothesis but this Small Form Factor computer
> has a unique (and probably expensive) power supply.  I opted to move
> the disk to a Dell OptiPlex 990 Small Form Factor computer and use that.

Is its PS also 240v? It might be a little more robust.

>
> The Dell, with the HP's disk, seems stable.  No rebooting.  This is in
> the same warm room, but the weather has changed.

Heat is the enemy.
>
> In the original HP box, I installed a disk that I had laying around (a
> 60G drive from a discarded laptop), installed Ubuntu 16.04, and have
> been running four CPU-bound processes for 24 hours.  No crash.  I
> admit that this is in a cooler room.  The heat and power load of a

If your house wiring is correct and all spiking load is connected to the
neutral bus from the same hot leg of the service, it is possible that a
spike and sag isn't affecting this room.

Even a 110v dryer motor can tweak some electronics. Although in general
most switched power supplies can handle a load of margaritas being blended
up on the same bus. A blender spike is quite small.

> laptop drive is less than that of a 3.5" HDD, but I would not think
> that that is significant.
>
> The computer is a couple of years old but still has a year of
> warranty.  There are confidential files on the disk drive so I'd like
> to narrow down the problem before calling in HP support.  Asking for a
> particular replacement part is more convenient that shipping the
> computer back to HP.

A line conditioner would be an expensive solution, but if the problem is
voltage sags related to any service upgrades affecting your neighborhood
household power, maybe in a few weeks, after they've tinkered the grid,
your transient problems with this particular unit will end

I think rule of thumb says if you can't see the lights dim, it's not a
significant brownout sag.

However, different parts wear differently under different circumstances.
One part will suffer lots of minor spiking abuse and live up to mean time
between failure and some parts won't last as long.

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