Mystery Sulfur.... reminds me of a problem we had once, turns out the sulfur
was coming from a rubber compound that we were using... Don't know of any
sulfur compounds in resisters though...
got me! - Bill Brooks


-----Original Message-----
From: Vernon Richard [mailto:[log in to unmask]]
Sent: Wednesday, June 14, 2000 4:12 PM
To: [log in to unmask]
Subject: [TN] Resistor termination disappearing


Hello, TechNet!

We're working a problem with a resistor where the value increases due to
some chemical reaction. The reaction takes place between the termination
silver and sulfur present on the component. This causes the resistor to
change value due to the silver being depleted from the connection interface.
We don't introduce any sulfur in our processes (std smt w/ aqueous wash, Dow
1753 coated), so we suspect that it comes from the resistor manufacturing
process. We also seem to have a gap in the glassivation over the interface
area.

Has anyone seen this before? What was done to eliminate the problem? Help-
our customer is getting very concerned!

Thanks. Rick Vernon

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