Why it is sometimes necessary to re-seat a board or chip
dkelvey at hotmail.com
Wed Dec 31 00:41:06 CST 2008
> 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?
To my knowledge, it is pure gold. It is difficult to plate
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.
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