Vernon,

Sulfur is used in the manufacturing of "brown" cardboard. The dust has a high level of
sulfur in it!

D. A. Douthit

Brooks Bill wrote:

> 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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