Onkel, I don't know.

As I related in a post some time ago, I thought I finally had a power stage failure to analyze, when its replacement seemed to "fix" the no-spark problem.

However, I was in a hurry, and did not verify the original repeated the failure. That very suspect unit is the one hanging in the air now over a year later. I was hoping to get my brother to put a microscope to it and give you the answer to your question, at least for this one example.

I suspect most of us are not as diligent as you were to re-test the suspect unit, so the replacement and its cost are instantly justified. You're welcome to pop your dud in the mail to me, and get a report (eventually) in return, but even then, just the few we are allowed to see do not comprise a large enough sampling to determine the usual failure mode. But, heat cycling over time is certainly the largest stress to assembled electronics.



benstein@cleanflametrap dotcom
--
Art Benstein near Baltimore

Wisdom comes with age, but sometimes age comes alone.