>
> I'm seeing odd failure modes- suddenly, other frequencies appear in the
> spectrum.  It only happens at a particular temp, which varies from one
> osc to the next.  Above or below that temp, the effect vanishes.  Some
> of them, the temp is above the operating range.  Others, it's right in
> the room-temp ambient breadbasket (which is how we found it, of
> course).


How carefully was the crystal desgined into the oscillator?
I can think of a few reasons why this might happen.

No one seems to know WHY this particular failure mode is occuring.
> No one seems to know what the implication of this failure mode is
> (i.e., if some of these slip through, is that a Portent of Doom for that
> product, or will that oscillator last the effective lifetime of the
> device?).


Been there, done that.. :(  It wasn't pretty.


> No, it isn't pleasant.  We can't tell if it's a process problem (handling,
> baking, etc.) or a manufacturer defect in the parts.  Since nobody
> knows why it's failing, we don't know where the flaw was introduced.


Has anyone pulled the suspect crystals, and checked them against the specs?

Failure analysis isn't something that I routinely do for other companies,
but I would be interested in taking it on as a project.


-- 
> Feel the power of the dark side!  Atmel AVR
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