From bgvocals@yahoo.com Tue Jun 07 12:45:01 2011
Subject:Re: NUMA (or whatever) - should you wait to buy?

Great comments Ryan. As I understood it from IC designers, they said most early
electronic failures (infant mortality) were cause by mechanical problems with
bonding wires in the IC. Temperature cycling tends to exacerbate those
problems. Add a shock table to things like you guys did and I would expect an
extremely low return rate, especially during first-hours of operation.

Lou

________________________________
From: ryan
To: CloneWheel@yahoogroups.com
Sent: Tue, June 7, 2011 2:45:30 PM
Subject: Re: [CWSG] NUMA (or whatever) - should you wait to buy?

I don't know what test procedures are used by consumer musical instrument
manufacturers
these days. In the early 80's I worked as a test technician for a commercial
microprocessor-based test equipment company. All new circuit boards were
individually tested in a test fixture and any problems that showed up were
repaired. Once a partially assembled unit passed all tests on the bench it was
placed in a burn-in chamber which cycled through a variety of temperatures
ranging up to about 150 degrees for up to 48 hours. There would usually be some
failures during burn-in which were repaired and then placed in burn-in again.
After burn-in each unit was strapped to a shake table which would subject it to
a variety of vibration levels for a specified length of time. After this the
unit went through final assembly and was bench-tested again. If a unit passed
all these tests it was usually reliable. Our return rate was very low. Of course
this physical testing would mainly reveal hardware problems but on occasion I
would come across a software bug which the engineering department would fix.

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