You can almost guarantee that the board they had trouble with had open vias
under the components, and wave soldering filled the vias and made a little
dome on the top side, ready to make short circuits to any metal bodies.
Properly tenting thye vias would fix that problem.

Cheers...

 

Andy Kowalewski

0424 432 235

-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of wheels
Sent: 2009 03 19 01:44
To: [log in to unmask]
Subject: [DC] Traces and vias under components

Guys,

We have a customer which we are designing a mostly SMT board for that 
requires all traces and vias not to be under components. This would also 
include any planes being under the components. I guess in the past they had 
a board designed by some else that had a shorting problem with traced and 
vias under the components. They are insistence that this is the way it has
to 
be. Has anyone else had experience with this sort of demands? This is not
for 
space, military, high voltage, high vibration or a medical application. Can 
anyone think of anything we could tell they to change their mind?

Thank you, 
wheels

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