Re: Predictive failures

"Don Y" <blockedofcourse@foo.invalid> wrote in message
news:uvjn74$d54b$1@dont-email.me...

Is there a general rule of thumb for signalling the likelihood of
an "imminent" (for some value of "imminent") hardware failure?

My conclusion would be no.
Some of my reasons are given below.

It always puzzled me how HAL could know that the AE-35 would fail in the
near future, but maybe HAL had a motive for lying.

Back in that era I was doing a lot of repair work when I should have been
doing my homework.
So I knew that there were many unrelated kinds of hardware failure.

A component could fail suddenly, such as a short circuit diode, and
everything would work fine after replacing it.
The cause could perhaps have been a manufacturing defect, such as
insufficient cooling due to poor quality assembly, but the exact real cause
would never be known.

A component could fail suddenly as a side effect of another failure.
One short circuit output transistor and several other components could also
burn up.

A component could fail slowly and only become apparent when it got to the
stage of causing an audible or visible effect.
It would often be easy to locate the dried up electrolytic due to it having
already let go of some of its contents.

So I concluded that if I wanted to be sure that I could always watch my
favourite TV show, we would have to have at least two TVs in the house.

If it's not possible to have the equivalent of two TVs then you will want to
be in a position to get the existing TV repaired or replaced as quicky as
possible.

My home wireless Internet system doesn't care if one access point fails, and
I would not expect to be able to do anything to predict a time of failure.
Experience says a dead unit has power supply issues. Usually external but
could be internal.

I don't think it would be possible to "watch" everything because it's rare
that you can properly test a component while it's part of a working system.

These days I would expect to have fun with management asking for software to
be able to diagnose and report any hardware failure.
Not very easy if the power supply has died.

>
I suspect most would involve *relative* changes that would be
suggestive of changing conditions in the components (and not
directly related to environmental influences).
>
So, perhaps, a good strategy is to just "watch" everything and
notice the sorts of changes you "typically" encounter in the hope
that something of greater magnitude would be a harbinger...