On Wed, 26 Aug 2015 14:54:24 -0700, you wrote:
>Thanks muchly guys.
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>I guess being new to the art of PCB fabrication, Im trying to figure out how I could get as close as possible to the appearance of the (we think) vintage boards seen in my ebay link.
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Ok....
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>When I asked Don Lancaster about the boards he used in the prototype, he said this:
>The original boards were G10 green. Original artwork was 4x tape and dots followed by litho camera reduction.
That's the camera process and photoetched.
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>I guess my question is, can I get green copper clad boards that look like the ones in my photos? Ive read through the laser toner process and it seems to me if I get boards that visually look similar the end result shouldnt be that much different if I use a newer (easier) process. But in looking around ebay, etc Ive not seen anything that has quite the right vintage look.
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Ok, not a quite easy thing to do. Most boards are generated from
Gerber files. When those boards are done, they have silk screen,
solder mask, and plated through holes done.
Laser toner will give you a duplicate of the pattern, but will not do
plated through holes, nor will it do silk screen. (you can do silk
screen, and it is possible to do solder mask, but it will involve a
process for each item.) Plated through holes are very very rare to
achieve.
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>Im also curious as to how the person that created those ebay boards got all the markings in white on the top side (ie. the SWTPC logo, transformer footprint, etc). Any thoughts on that? Im guessing Don didnt have anything like that with his prototype boards.
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Silk screen through toner transfer (see pulsar website) is quite
possible ∗if∗ you use toner transfer at all.
Depending on the tools you use to make the boards, you can get quite
close.
Let me explain a bit, since it's not obvious at first glance. The
problem is the traces themselves. In tape generated boards, the
draftsman did the curves by hand, and often did curves all over the
place (look at old Tektronix boards). Ground pours were not all that
common.
In computer generated boards, you get mostly straight lines unless you
take pains to allow curves, (and that most likely means no
autorouters). You can get a ground pour quite easily.
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>Speaking of which, I may get an answer on what the prototype boards actually look like. I emailed the research department of the Computer History Museum that has that unit, and they offered to attempt to open it to have a look, provided it was designed to be opened and no damage will happen.
You ought to get results, then.
Harvey
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>Brad