Cloning with a NuXT
For years I have been gazing longingly at well-made YouTube videos about ’80s and ’90s IBM and Tandy machines, but because I live in the United Kingdom those computers are either near-impossible to find or ridiculously expensive. So when I saw this YouTube video from LGR about a modern day clone, and then discovered it cost about the same as a modern games console, I immediately leapt into action!
The board described in the video is a hobbyist open source logic board called the NuXT. It primarily aims to be compatible with the IBM Personal Computer XT and uses a combination of salvaged parts and modern creature comforts. This means it pairs an original Intel 8088 CPU with on-board flash storage for CMOS, and the operating system is installed on a much faster CompactFlash card instead of a mechanical hard drive. You also don’t need controller cards for graphics, sound and storage devices if you don’t want them because those are already integrated into the board by default, and it works with both the original and modern peripherals.
It is a very cool piece of kit indeed and it is a privilege to own one, but of course there are limitations. As LGR covers in his video there are games and software that work fine with the original hardware but do not with this clone system. However, for people like me who can only really hope to use the original hardware on occasional trips to computing museums, this really is the next best thing.
As getting hold of the required parts for an upgrade in the future is deeply unlikely I bought the Monotech NuXT with its Intel 8087 co-processor and 512K VRAM options. I also took the opportunity to order a reproduction AdLib sound card at the same time because those are surprisingly hard to get hold of now that hobbyists are buying them all up on eBay.
For that added sense of authenticity I also bought a reproduction buckling spring keyboard from Unicomp, a company that uses the very same factories and equipment that produced the original IBM “Model M” keyboards. This was definitely one of my better life decisions because buckling spring keyboards are absolutely wonderful to use.
However, it would be quite some time before I could actually assemble the machine because it can take a while to ship things across the world. It has also taken me nearly three months to write this blog post because I was distracted by other projects. But despite those things I hope as you read this blog post you can see that building and using this computer has been a very fun experience for me, and I think this project is also a great demonstration of how valuable patience and perseverance can be when you are working with old hardware and hobbyist-made components.
The picture at the top of this blog post was taken on the day this text was published. The rest were taken when I built the machine on 2019-09-11.
This entire project was an exercise in patience as it took over a month for the first group of components I ordered to arrive. That is unsurprising given very few of them were available from UK sellers and therefore needed to be shipped from areas as far flung as New Zealand, Hong Kong, Germany and the United States. My refurbishment projects are usually cheap and eco-friendly, but it is fair to say that this unusual project was neither of those things!
The first batch of parts were ready on Saturday 7th September 2019, but I had a problem. The appropriately “retro” mini-ITX case I ordered could fit the NuXT board, but it was too shallow to fit the reproduction AdLib sound card. In hindsight I should have seen that coming, and it just goes to show that however many times you work with old hardware or build weird computers, you are never too experienced to make mistakes. I stored that case away in my attic so I can potentially use it for a future project, but it meant I had to wait an extra week for a much larger microATX replacement to arrive. I also had to use a spare 500W power supply salvaged from an old gaming PC instead of the much more power-efficient one that was built into the first case I ordered.
There were some other parts I did not have to order for this project as I could just rummage around in my attic to find them. The 5.25″ drive bay adapter for the 3.5″ floppy drive, kettle leads, the beige LCD monitor I used initially, the cone speaker that I didn’t end up using at all, and most cables I needed for the peripherals all came from the bottom of cardboard boxes that I spent a Sunday afternoon picking through for useful parts.
During the build itself I discovered that a floppy cable I reclaimed from a dead Dell Optiplex desktop was not actually compatible with the Sony-branded 3.5″ floppy drive I specifically ordered for this project. As a result you will notice in the photos I used for this blog post that the floppy drive is not actually connected to the NuXT board. I had to wait another two weeks for a pack of universal floppy cables to arrive in the mail before I could start playing physical copies of DOS games, which was disappointing. Fortunately it did not block my enjoyment entirely, as I could just copy files from a modern PC directly to the CompactFlash card supplied with the NuXT board until I fixed the problem.
In the months that have passed since I completed this project I replaced the beige LCD monitor with a larger and better-quality Dell one that still preserves the 4:3 aspect ratio common to old CRTs. I also picked up a cheap serial mouse so I can play DOS games that make good use of it and experiment with early versions of Windows.
Assembling the Clone
Putting the system together was fairly straightforward. Monotech sent me the NuXT board already pre-assembled, so most of the work involved was figuring out where to plug in different power and LED cables. The only part that confused me was how to connect an external cone PC speaker. As the connector for the one I salvaged seemed to be different to those described in the instructions, and the cone speaker itself has a powerful magnet on the back that might interfere with other components, I figured it was better to stick with the PC speaker provided with the NuXT board.
You will notice in the provided photo that some of the holes in the board are missing screws. That would be because not all the mounting points seemed to be in the correct place, but enough of them were for me to still feel comfortable moving the machine around when I have to.
Similarly, I got quite nervous about the expansion card connectors not quite lining up with the slots provided by my case. With some “trial and error” I managed to fit the reproduction AdLib sound card without causing any damage to the pins or accidentally snapping it in half!
Unlike LGR’s video, the board I was sent by Monotech did have a rear faceplate. This was another reason I was not too upset about switching to a microATX case, as the backplate was actually too tall for the mini-ITX one and I would have had to remove it. It was still quite tricky to fit, but I blame that more on the case I had chosen rather than the board itself.
A particularly cool thing I noticed about the machine when I switched it on for the first time was just how quiet it was. Really the only fan in this system is the one in the power supply unit, but because that is never pushed anywhere near its full capacity, it just spins the fans at a constant speed. There are certainly quieter PSUs available to buy, but the one I am using is really not loud enough for noise to be a problem.
The only mechanical component is the floppy drive, but the noises that makes fill me with powerful nostalgic feelings of joy. Also they only happen intermittently and provide useful feedback about whether a disk is actually being read or not, so I don’t think suppressing those sounds would even make sense. I am aware that I could have chosen a floppy drive emulator instead and stuck to much more reliable USB flash storage for old DOS games, and I may well choose to do that in the future. But for now the tactile sensation of handling physical media I used in my childhood and early teens is something that might not actually be possible for much longer, so I am making the most of it while I still can!
When I powered everything for the first time I had every finger and toe crossed that everything would work, because I am notoriously bad at fixing software-related problems with old computers. For example, there is an Apple Macintosh LC II that has been sat on a shelf for nearly a year waiting for me to flash System 6 onto an SD card. The struggle is real!
Thankfully everything did work, and I immediately took the opportunity to make a
dd image backup of the CompactFlash card supplied with the NuXT board so it is easy to fix if I do something silly and break my fully-working DOS installation.
The PC speaker sound worked beautifully without any intervention, but I did spend a while scratching my head wondering why AdLib sound wasn’t working. I am not proud of the fact it took 20 minutes for me to figure out there was a volume control on the card itself that I needed to adjust!
I also took the opportunity to explore what was already on the CompactFlash card and used the demo games to verify that I had everything connected and configured correctly. Checking the BIOS output at startup to make sure the memory values and detected devices are all good is usually a good idea, and it was great to see that they were already correct and didn’t need any further changes from me.
When I packed up the computer ready to move it to an actual desk the only problem was a missing floppy drive cable, which was definitely my fault! I was really pleased that I did not have to do anything to fix the operating system or software once I had put this very cool project together, so kudos to Monotech for making installation and setup so straightforward.
I predicted at the time I would “experience many hours of joy with this machine”, and that has proven to be a very accurate statement! I look forward to many more lazy Sundays playing ancient and homebrew DOS games on this very cool computer.