Hello Peter,

A unit comes back with a "defective" tag on it. It is going to go to
the person who originally designed it, and be checked out with lots of
instrumentation? Of course not. It will go back into the factory test
process, and if it passes the factory test then it is classed as
working.

That would be a normal process.

If there is an obvious fault that will get fixed, and statistically
that will likely be the only fault, so that is OK. The problem is with
faults that are intermittent, or faults that don't get picked up by
the factory test. I've been in electronics design/mfg for 25+ years so
know this problem well; in my business we scrap anything that comes
back, just to make sure.

If intermittent is flagged this should cause more diligence in the
repair process. If the test folks can't duplicate the error there should
be further investigation, at least in cases that involve a lot more than
one unit. That's where the QC system should kick in with its database
information. Or in the med biz, that is where the QC system has to come
in on a mandatory basis.

My warranty avionics bill totals something like US$100,000 and that is
mostly Honeywell avionics, added up at list prices, over 2 years.

I wonder how they survive. I ran a business for several years and
warranty overhead was factored in on a "per product" basis. My boss
would probably have fired me with cause if I had ever failed to see an
epidemic trend in one of the lines we offered. It never happened but we
watched that stuff like hawks.

On the part of the user I'd be mighty concerned about what happens after
the warranty period ends. After that, every time the servo hangs you'd
hear that slurping sound coming from your bank account.

Regards, Joerg

http://www.analogconsultants.com