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Date: | Wed, 24 Jan 1996 12:24:14 -0600 |
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.int [log in to unmask]
The net list test protects you from BIG screwups where the whole lots is the
same - All wrong - but the same so it passes a learned test. These screwups are
just as often the customers problem as the FAB makers problem and is a very
good idea to net list test. Ever assemble a few hundred large PWAs and then
find they ALL have the power to ground short you designed in and in a hard to
rework place too?
As far as occasional opens / shorts. Sometimes the test is incomplete and not
detecting the error. This could be because a flip test will miss a few via on
surface mount PWBs. Or a missing pin or poor fixture design with a learned
program if they re-learn every lot.. Often the problem happened after some
thermal or mechanical event and wasnt there when tested
Larry Sternig
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*** Original Author: ipc.ipc.org!ipc.org! 01/24/96 095210
Resent-Date: Wed, 24 Jan 1996 07:37:52 -0800
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From: BOB HOENE <[log in to unmask]>
Subject: Electrical test efficiency.
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Would anyone who happens to be an electrical test guru provide the
relative efficiency of bare board electrical test and compare a "standard"
electrical test to a "net list test". The impetus for this is our in-circuit
test
department wondering why they occasionally still find opens and shorts
on "tested" boards. All responses and opinions greatly appreciated.
Thanks,
Bob Hoene
Marquette Electronics
Milwaukee, WI
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