When thinking of the first PCs, most of us might imagine something like the Apple I or the TRS-80. But even before that, there were a set of computers that often had no keyboard, or recognizable display beyond a few blinking lights. [Artem Kalinchuk] is attempting to recreate one of these very early digital computers, the Kenbak-1, using as many period-correct parts as possible.
Considered by many to be the world’s first personal computer, the Kenbak-1 was an 8-bit machine with 256 bytes of memory, using TTL integrated circuits for the logic as there was no commercially available microprocessor available at the time it was designed. For [Artem]’s build, most of these parts can still be sourced including the 7400-series chips and carbon resistors although the shift registers were a bit of a challenge to find. A custom PCB was built to replicate the original, and with all the parts in order it’s ready to be assembled and put into a case which was built using the drawings for the original unit.
Although [Artem] plans to build a period-correct linear power supply for this computer, right now he’s using a modern switching power supply for testing. The only other major components that are different are the status lamps, in this case switched to LEDs because he wasn’t able to source incandescent bulbs that drew low enough current, and the switches which he’s replaced with MX-style keys. We’ll stay tuned as he builds and tests this over the course of several videos, but in the meantime if you’re curious how this early computer actually worked we featured an emulator for it a while back.
Not sure what the specs are on the bulbs he was looking for, but maybe look at 70’s home stereo equipment. The time period is roughly the same, so supply chains would have had similar bulbs available for R&D and manufacturing groups. There’s at least one seller of replacement bulbs for those old stereos floating around on the forums like Audiokarma.
I should not have been, given its era., but I was surprised by how large the Kenbak-1 was.
We used to get SciAm when I was a kid. I remember that cover.
The magazine is not what it once was.
Sad but true. Less and less hard science, more soft science and politics, as it gets thinner and thinner. Almost dropped my subscription last year. May do so this year.
SciAm was once my absolute -favorite- magazine, and for many years I alternately subscribed or purchased it at the newsstand every month. While I enjoyed most all of the content, my first stop every month was the Amateur Scientist column.
First, that column went away. Then, the magazine took a very sharp turn to the left. The ratio of politics to “science” went through the roof and the last issue I held in my hands was so preachy I finally decided enough is enough.
I don’t own a bird with a cage that needs to be lined, so there is no longer any purpose for having that rag around.
I dropped my subscription about +15 years ago when the mag was overrun with the CC crowd. Sadly, most of the back issues I had hit the dumpster when I moved. Though I did save a few, like the one where the “Amatuer Scientist” column showed how to make a DIY laser. Powering that up is not for sissies… LOL!
The change happened around the turn of the century. I noticed it right away and stopped renewing. Around 2008 or so, the chief editor was being interviewed by Charlie Rose (remember him before he got canceled?) He basically admitted to going full in with a climate change agenda.
that looks not like an Olivetti 101 at all…
New challenge for retro-computer enthusiasts who also make things…
Build a 3d printer to be controlled by your computer using only parts that were available in it’s era.
Obviously this isn’t going to run a slicer with a GUI representing an STL. Just executing some hand-coded G-Code would be more than sufficient.
I’d love to see just how far back in time this concept can be pushed.
Tubes for the power controls? Don’t recall good power silicon back then. Everything else should be the same because there were commercial extruders available, as well as precise plotters, although really big
“Tubes for the power controls?”
You mean the heaters? I was just thinking relays but sure, if you want to do it with tubes I’d love to see what you make.
Then again, clock cycles are going to be a bit too precious to consider controlling the temperature via computer. I guess it’s some sort of thermostat then.
Or did you mean the motors? I just Googled it and steppers go back to the early 1900s. I have NO IDEA what they controlled the first ones with! But people were playing with robotics in the 70s weren’t they? There must have been some sort of analog or ttl based motor driver.
But if not… maybe even use plain old DC motors and rely on timing for distances. That’s probably going to suck. But the project wasn’t to make a GOOD 3d printer. It was more to make whatever a hobbyist would have come up with back then if they had the idea. At least that’s how I saw it. Besides, even a really crappy printer taken back in time to the 70s would probably be pretty exciting to anyone who saw it.
“there were commercial extruders available”
I bet that cost an arm and a leg! And was probably huge too! I was just thinking early rep-rap tech where they used nichrome wire stolen from an old toaster wrapped around a bolt for the hot end. There were versions of the nozzle one could make from a bolt with just a drill press or better ones for machinists with lathes. I don’t think there was much to those that didn’t exist back then… except… did they have muffler putty yet? I’m sure there was something that could substitute. And of course, the previously discussed temperature control. Maybe something with a bi-metal strip tacked at one end to the heat block?
Thyratrons (gas-filled tubes) became available in the 1920s, and I saw them being used in 1970. Thyristors (power semiconductors) have been available since about 1965.
My own take on the venerable KENBAK-1.
https://hackaday.io/project/178787-25-scale-kenbak-1-personal-computer-reproduction
This scale reproduction includes a Python based KENBAK IDE with an Assembler and built in Debugger which can be run stand-alone if you just want play around with the remarkably advanced instruction set.
I was luck enough to get one of Grant Stockly’s Kenbak-1 Series 2 kits way back in 2007.
It was an absolutely incredible work of art, and even was autographed by John Blan(kenbak)er, the creator of the original.
Grant’s web sites are still up, although not secure (http, not https):
http://www.kenbak-1.com/
My build:
http://www.stockly.com/forums/showthread.php?t=555&page=2
Egads! 46 7400s, 15 7410s. 10 7454s, an AND-OR-INVERT gate. The 7454 is one of those oddities that are functionally different than the 74LS54.
The Kenbak was a bit-serial machine: none of those fancy parallel bytes or even nibbles. A 4 bit ALU chip, the 74181, became available in 1970, which makes me wonder if a more effective design would have been possible even with the limited resources available then. Nonetheless, an impressive design.