Open Source CoCo Cartridge Shell

It’s no secret that I love 3D Printing.  It allows the everyday individual the ability to prototype and produce enclosures that are professional.  Or the ability to print that figurine that you found on Thingiverse.  But whatever your 3D Printing Desire is, you know it’s the wave of the future for the Maker.  And you likely want in.

I only recently bought my first 3D Printer.  In March of this year I became the proud owner of a Da Vinci Pro 1.0 printer.  And it while it does take experimentation to master, it is very rewarding.

Several years ago I became the proud owner of a Tandy CoCo 2 64K computer.  I didn’t have any cartridges for it.  But I did have a tape recorder and a great understanding of BASIC.  I wrote several programs, but that was mostly just to tinker.  And to show my son exactly how things were done back in my youth.  And while I occasionally looked at buying some cartridges for the CoCo, I never did.

Now another well known fact is that I love playing with electronics.  I have just about every tool that I could need as a hobbyist.  Up to, and including, a 54 Channel Logic Analyzer.  Being this well equipped, I eventually decided that I just needed to sit down and design a PCB for the cartridge.  And I set out looking for schematics for the boards themselves.

It was at this time that I came upon THIS WEBSITE.  Someone had already created a pretty decent PCB, and uploaded the files for the world to use.  So I thought to myself,”Hey, why don’t I just use this guy’s stuff!”  And so I downloaded the Gerbers, and ensured that all was OK.  I then uploaded the files to my favorite board house, Elecrow.  And once paid for the wait was on.

Now if you never have done business with Elecrow, I’ll fill you in.  Once you pay for the boards they get right to work.  Usually having your board in production within two days.  Once in production it usually takes about three to four days, and they send you an email letting you know that your boards are shipped.  With this email they’re nice enough to send a picture with your  vacuum packed boards and the invoice for your order.

About three weeks later I discovered a package in my mailbox.  Once opened I discovered that not only did I receive the 10 PCBs that I ordered for about $15.  But I also received 5 more “bonus” boards.  I guess they had leftover space on the ENIG Finish panel, and just decided to be nice.  I’m not complaining.

Upon inspection, I honestly could not be happier.  While there are a few small issues, such as the solder mask not quite sticking to the small traces of the ENIG finish (see below), the boards looked great.  I promptly soldered up a “test” board so that I could test individual EPROMs in my CoCo.  I feel this is important to do before committing to soldering an EPROM into a board.  You never know if it’s going to work as programmed.

The boards, and the EPROMs, turned out to work great.  But this left me with another problem.  I didn’t have any cartridge shells.  And moreover, I didn’t have any way of knowing the dimensions of the normal CoCo shell.  Nor if these boards would fit in the every day CoCo shell.  Well, I guess I’ll just have to design my own.

After a few days in AutoDESK 123D Design (Why did they ever discontinue this awesome software!?!?!), and a few test prints of course, I had a basic design.  Ready to test.  And the best part about it, it was practically free….because, I made it!

While I wouldn’t say that this design is authentic to the styling of the original cartridges, I will say that it is very close to what you would expect of a cartridge shell from that era.

And the best part, I’m providing the STLs for free over on Thingiverse.  You can find them HERE.

And you can watch my YouTube video below.

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