16 May
2002
16 May
'02
6:20 a.m.
I've never attempted to scratch glass with 'em, but I've found that IC
leadframes are made of ferrous metal. I routinely use my "magnet on a stick"
to pick 'em up. There's lots of stuff that you can scratch with pretty soft
steel. One thing to keep in mind is that while aluminum is pretty soft,
aluminum oxide is a very good abrasive. That's not the only material with
that characteristic. What's more, soft materials tend to pick up bits of
other materials, and can scratch things with what they pick up. I've
scratched one scanner bed by careless handling of PC boards I was scanning. A
little care is all it takes. It's particularly important to be aware of where
connectors, test points, and jumper blocks are located so you can manage their
contact with the scanner bed.
Dick
----- Original Message -----
From: "Tothwolf" <tothwolf(a)concentric.net>
To: <cctalk(a)classiccmp.org>
Sent: Thursday, May 16, 2002 11:42 AM
Subject: RE: [CCTALK] [CCTECH] scanners & circuit boards...
On Thu, 16 May 2002, Davison, Lee wrote:
That is true. I had totally forgotten about that. The window of an EPROM
is made of quartz for that very reason. That is also why EPROMS are much
more expensive than a PROM that is exactly the same in all other aspects.
-Toth
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Tothwolf wrote:
Are you sure? I've scratched glass with metal before, though not with a pc
board. Most component leads (excluding some of the newer resistors and
capacitors) are made of a tin plated copper or a copper alloy anyhow, so
it would seem that they would be less likely to damage something than say,
steel.
Since we are talking about scratched glass, do you have any ideas on how
to remove scratches from the face of a CRT?
I'd be more concerned with accidentally
scratching the glass bed of
the scanner due to sharp component leads.
You can't scratch glass with metal. What you can do is leave a thin
trace of metal on the glass. Gewelers rouge will easily remove this is
nothing else will. I guess
that there is a slight possibility of degrading the contents
of an EPROM if its window isn'tcovered.
Glass is opaque to UV so you won't erase EPROMs either.