Hi KK -

You mention that these failures generally occur after an extended period in
"burn-in".  Does your burn-in operation contain any temperature cycle, such
that the assembly might go through the dew point and accumulate condensing
moisture?

Another possibility, along the same lines, if it receives condensing moisture,
it may also be picking up some fluid borne contaminants from the test
area/chamber walls.


Regards - Kelly

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