From: cclist at
sydex.com
To: cctalk at
classiccmp.org
Date: Tue, 30 Dec 2008 22:18:45 -0800
Subject: Re: Why it is sometimes necessary to re-seat a board or chip
On 30 Dec 2008 at 21:09, Sellam Ismail wrote:
So this is why a re-seating of certain cards,
connectors and ICs
oftentimes cures a fidgety system.
Maybe the scrappers know this, but how often is pure gold used as the
contact material on edge connectors? I thought that an alloy was
plated as pure gold is very soft and doesn't withstand too many
insertion cycles. Anyone?
Cheers,
Chuck
Hi
To my knowledge, it is pure gold. It is difficult to plate
alloys.
Another reason why boards need to be resetted is because
there are differences in the materials. Gold to solderplate
will cause problem over time.
Keeping air and moisture away from the contacts will avoid
problems. This is why I have been using things like DC#4
on contacts for my machines for years. I've never had to
reset any of my machines boards or ICs that I've applied
the grease to( not ever ).
But back on the plating, it is done very thin. 15 or 30
micro inches are common. The nickel ( as well as a barrier
to the copper ) provides the stiffness.
The gold is so thin that a few minutes with a pencil
eraser will remove most of it.
That is why I hate to see people using this method to
clean boards. I find that this can more properly be done
with some damp lense paper. The eraser often leaves a
little of the rubber as well that will eventually release
the sulfur, causing the need for more cleaning.
Dwight
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