Homebrew_PCBs

Hi there,

The unit appeared as a project in the Sep 1973 edition of Radio Electronics.  There was a slightly different unit featured on the cover of the magazine (more refined, different keyboard). For a few bucks you could send away for plans to build your own, using either prepared boards (produced by Southwest Technical Products) or by making your own using artwork supplied in the construction booklet, like so:

I have pretty much everything I need now to kick off the project, including 1973 vintage chips and the correct MDS keypunch keyboard, to match the prototype.  Unfortunately the prototype was, as most are, a one-off, and did not use the boards that were ultimately manufactured or described in the plans.  There are no pictures extant of the inside, although talking to Don it sounds like it was fairly close to the kit version in the end.

Anyway, at this stage my best hope for now would be to recreate the boards per the above plans.  I'd prefer to do it with period-correct materials (or at least get a period correct look).  I'd even like to use period-correct processes (foil tape?  I'm not exactly sure how they did it in the old days).  But I'm not necessarily opposed to going modern via the toner method.

I guess I am just hoping to get advice.  For reference, here are some boards that sold on ebay recently:

It's unknown if these were actual SWTPC manufactured boards or a hobbyist doing their own.  It's been speculated by those more knowledgeable than I that it is probably the latter, since the copper traces on the one side weren't tinned, which was normal practice for a manufacturer.  They did think that these possibly dated to the early 1970s though.

Anyway, any advice on how to proceed and achieve something visually that looks like these (and hopefully works, too!) would be greatly appreciated.

Brad

 

Cool project Brad!

You have the PCB layouts in the reprint PDFs, just print them out (be sure to set no size reduction) and make sure they fit the components, then transfer to PCB and etch. Lots of ways to do that. Most all are documented here:
http://techref.massmind.org/techref/pcbs.htm

Let us know how it goes.

-- 
Cecil - k5nwa
http://thepartsplace.k5nwa.com/

>Thanks muchly guys.
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>I guess being new to the art of PCB fabrication, I’m 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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>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.”

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>I guess my question is, can I get green copper clad boards that look like the ones in my photos? I’ve read through the laser toner process and it seems to me if I get boards that visually look similar the end result shouldn’t be that much different if I use a newer (easier) process. But in looking around ebay, etc I’ve not seen anything that has quite the right vintage look.
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>I’m 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? I’m guessing Don didn’t have anything like that with his prototype boards.
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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.

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>Brad