Intro

Ever since it was released I was fascinated by the Jupiter ACE.
It was introduced in 1982 by a company named 'Jupiter Cantab' as 'probably the fastest computer in the universe'. Mainly because it was the first (and only) computer that runs Forth as it's main operating system. At a time when every other computer ran BASIC this was a remarkable choice, and it turned out to be a bad one. Only hardcore programmers dared to take up FORTH, and in the end only 8000 units were ever sold. Making them very rare and expensive nowadays, so I will probably never own a real one.  Of course there was no way I could ever afford one myself, and at home we already had a TRS-80 so the ads and reviews in computer magazines was all I could look at.

Building a replica of the Jupiter ACE  has been done before, and the super accurate replication of the PCB by Grant Searle is probably the best example. The schematics were redrawn later by Bodo Wenzel in ORCAD, and a modified version was made by Isidro Nuñez Blanco De Arenas. Both builds were done 2003-2006 ( which shows if you look at the design of their websites), and things have changed a bit since then. PCB manufacturing is much cheaper now, and it's also easier to create custom plastic parts. Because what's lacking in all these rebuilds is the actual housing, which to me is a huge part of the charm of this machine. And using a 3D printer it cannot be too hard to replicate this.

Actually, since I started creating this, some others have popped up (or I just did not find them at the time). There used to be a kit sold from Bulgaria by 'oricfan' but that one is hard to find these days. The most recent 'ACE' compatible kit is called the 'Minstrel 4th' by Tynemouth Software. Which is probably good, but (as mentioned on the site) is just a board, and will not fit the original Jupiter ACE housing.

There is the Jupiter-II, a beautiful version consisting of two separate PCBs. Which (as far as I can see) was created somewhere 2019-2020.

And of course I recently discovered that  people on the Jupiter ACE section of the K? Forum have created an almost identical board, in about the same time-span (2019/2020). They chose to use Cherry keys for the keyboard, which definitely will be a huge improvement in usability, but does not really add to the authentic look and feel.

Anyway, this is my recreation, and it worked out quite well. First the PCB:

My version on the right, Grant Searle's image of the original board on the left. I tried to stay close to the original, but I had to reposition the RAM chips, and replaced the RF modulator with a video output circuit. 

Second: the housing. This was recreated from photo's, so its not 100% accurate, but it looks a lot like it:

 

Mine on the left, original on the right. I did have to compromise a bit on the keys. My FDM printer cold not handle this much detail, so I had to increase the font a little, and replace the text buttons like 'SHIFT' and 'ENTER' with symbols. I also made a mistake when routing the keyboard, so now my 'Control Shift' key is on the left, next to the Shift, instead of next to the Enter key where it should be.