Re: Spontaneous unclean reboots

Curt wrote:

On 2008-09-22, Baron <baron.nospam@xxxxxxxxxxxxxxxxxxxxxx> wrote:

This morning, the psu blew and there was a smell of burning rubber and
hellfire and I turned off the machine.

A common cause of exploding PSU is bad caps in there. That can also
lead to failure of the capacitors on the mainboard.

Reminds me of a pc we had in a lab (maybe corrosive environment) which blew
the PSU with similar enduser experience :) - a popping sound, smoke and a
strange smell, and of course it was dead as a brick. Not only the mainboard
was fried, even the harddrive had turned into a paperweight.
Fortunately the (gpib-attached) expensive lab device survived.

Oh.

To make a long story short, I bought a new psu and installed it and am
keeping my fingers crossed.

That should rule out a PSU problem and hopefully cure the reboots.

So far so good; up several hours now without rebooting.

I'll let you know if the machine explodes on me.

Have you checked for bad caps on the mainboard ? They can often cause
spontaneous reboots. Particularly the ones in the CPU PSU. The bad
ones usually get much hotter than the others.

I don't know what caps are, so I couldn't check for bad ones. What do
they look like when they're bad (or good)? Do you check them visually,
or some other way?

Have a look at the example pictures on www.badcaps.net.
If you see bulged capacitors or even brown stain on top of them, you have a
reason for instability. These caps are part of the power conversion
circuits around the cpu, which change the 3.3 or 5v supplied by the psu, to
something like 1.5V for the core, and smooth the resulting high-frequency
intermittent voltages.

.

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