I bought and built one of these SWTPC computers. I even wrote quite a bit of software for it and had it working with the SSB disk drives, a Teletype 43 and later a SWTPC VDU/Keyboard combo which was in some kind of mouleded blue/cream case. I later also interconnected the SWTPC computer to a broadcast teletext receiver which let me save the "pages" to floppy disc. I also made my own S100 cards for memory and interfacing to Motorola exorciser boards. Everything was horribly expensive in those days amd one had to save up just to buy another 1K of memory! I'm pretty sure I still have some of the manuals tucked away somewhere. Sadly, I don't have the SSB DOS software you are are looking out for. Sadly all the hardware got ruined in a flood many years ago. Great memories - many thanks and the best of luck getting it operational. I still have 6800, 6821, MC14411 and 6850 Moiorola chips in anti-static tubes along with some 2102 memor chips (they were really fussy about static!).

The 6800 is one of my favorites. I have two 6800 system units, the AC-30 tape unit, several CT-1024s, the rare PR-40 printer, the ultra rare GT-6144 graphics board and the almost impossible to find joystick. The thing takes up an entire desk and a half when fully set up and the powerup sequence reminds me of a jet with all the switches!

I took a train trip for 1.5 hours to visit a SWTPC shop in the city of Delft, one of the first "computer shops" in the netherlands, I was amazed by the enormous capacitors inside. And yes, they sold fully assembled machines, and also the terminal and some printers. I remember seeing a small cash register printer (40-columns) that was fitted on top of a square metal box.

I worked at a company that used the 6809 variant of this machine in the late 80s. My first day on the job I walk in to find a coworker standing on a rolling chair with a watering can pouring water into the case of one of these. Of course, it was turned ON at the time. After I picked my jaw up off the floor and we were properly introduced, he related that this particular machine had a crack in the motherboard no one could find, so they kept a thin layer of water in the bottom of the case to keep the MB swelled up and the mysterious crack sealed so everything worked. The problem was the water would evaporate, and so it had to be "refilled" when the machine started getting flakey; the plastic standoffs made this possible. This company used the 6809 variant as a central processor for a passel of "remote processors" (an in-house built version of the same machine) that monitored sensors and responded to the central processor via phone lines, hardwired, or radio broadcast. The central processor stored data on a dual tape drive (DEC I believe) and my job was, among other things, to duplicate the central processor function on an Apple 2, and later an IBM PC. I did a few other things for them, including the code for a new kind of remote processor with different sensors. Robin or Don: if you're reading this, look me up. J

Never heard of? I was about 12 or 13 years old and was drooling over that computer back in the 70's. At that age and at that time it might as well been a million dollars!

As a radio amateur as well as a retro computing enthusiast, it gives me great pride that radio amateurs of the '70s were a key demographic of early adopters of kit micro computers. And as an added historical bonus, Motorola was birthed in the 1920s, one of its earliest products being a car radio (not amateur), hence the name "motor" plus "ola" (derived from "Victrola").

It's imposible to get tired of the "was saved from e-waste and actually given to me" sentence. Kudos on you for this machine, can't wait to see it running.

A SWTPC 6800 was the first computer I had seen in person. The man who owned it used a teletype for I/O. That was probably in late 1975. Thanks for the trip down memory lane. BTW, RAM chips were VERY sensitive to static electricity in those days. So often new RAM was damaged and so had to be tested as part of installation. Also, since that is not a switching power supply, any short will most certainly cause smoke and likely cause a trail of destroyed components. Have fun. :-)

I bought and built (kit) 3 of these puppies! The 6800 family of CPU's had one of the best instruction sets around!

So much memories. I have worked as a young trainee then beginner engineer on these machines. Actually only on the SWTPC 6809 as far as SWTPC-branded machines go. It was a very advanced machine with RAM page mapping allowing for up to 768K of RAM on an 8-bit CPU, running a small Unix-like O/S called UniFLEX. As for the 6800, the French manufacturer Goupil was producing a machine that was very much inspired from this one from '79 on, the Goupil (the blue gen.1 and red gen. 2). Bus-based too, almost a clone actually, but a complete computer with a video controller, keyboard etc. I still remember the ROM monitor commands (was that MICMON?). It ran the FLEX 6800 o/s which was rather advanced for its time, booting from 5.25" or 8" floppies.

For a few years, a gentleman by the name of Michael Holley used to exhibit his SWTPC 6800 at VCF East. He had built the thing back in the 70s, and knew about every little nook and craney of that machine. There's a good chance if you come across online documentation about this system, it might very well have been hosted by him at one point.

Brings back fond memories of when I soldered together my first computer (Netronics Cosmac Elf - RCA 1802 with 256 bytes of ram). Later built (soldering again) an S100 bus based 8088 system. 32 kb ram and 2 8 inch Shugart drives running CPM. Those were the days. I look at my iPhone now and smile.

We built lots of things from SWTP. We used a number of their small audio amps. And we called the company Sweet Pea.

This brings back many memories! I assembled several of these for customers while working for a distributor that carried the SWTPC product line back in 1976-79. This computer was designed to be as inexpensive as possible to buy. Using the MIKBUG rom monitor instead of a front panel full of switches and leds was a lot cheaper, though it did force you to have some sort of teletype or terminal to use the machine. The SS50 bus using Molex pin connectors was cheaper than gold fingered card edge connectors like the S100 bus used. The machine was simpler, easier to understand and a lot could be done with it. The 6800 was an under appreciated 8 bit CPU for its time.

Fascinating insight into 70's tech. Thank you Adrian, look forward to the trying-to-get-it-run video.

Somebody loved this, I can tell it was an amateur who did everything themselves and probably learned as they went along. The dry lumpy looking solder re-work along with the Flux being left on the board as well as the lifted and re-worked solder traces are all dead give aways.

Nice, years ago a work collegue had one of these (but in a wooden box). I wanted to get into the 6800, and this SWTPC machine had all I needed. So I grabbed a copy of it's memory map and I kind of cloned it. Apart from the disk controller, I didn't copy their design, I used my own design, that perfectly copied it as far as software was concerned, so I could use all their software. Mine was built entirely with wire-wrap, it had 3 serial ports, floppy, and 40KB of static ram using 2K ram IC's (6116). I also built the floppy drive into the enclosure, but with provision for an extra external drive via a 37pin 'D' connector. Pity I cannot post photo's here.

Thank you so much for producing this video - it brought back so many memories from when I'd just graduated in EE and courses in digital electronics and computers were rare and new, often with xerox'd handouts rather than textbooks. I read all the magazines but a new engineer's salary still couldn't touch even the kit versions. I discovered the Motorola MEK6800D2 evaluation kit and begged one off of a Motorola engineering rep over the phone (still had to pay for it). Not my first electronic assembly but it didn't work when I finished. I found an old Army electronics technician who let me watch as he went over the circuit carefully - he discovered two traces shorted together where the etching was incomplete and scraped it with a sewing needle until the kit leaped into life! 128 bytes of RAM which I upgraded to 256 bytes after waiting for my next paycheck. Display was a huge issue since terminals were way too expensive as were TV modulators. The 'D2 kit got around this with the included hex keypad and LED display - I learned to hand assemble 6800 code and remember typing in a program for 10 minutes while a friend watched. It worked but all it did was blink one LED! My friend almost hurt himself laughing and told everyone the story anytime the subject 'computer' came up. Sadly the 'D2 was recycled at some point. I'd love to have one now but they are way too expensive on e-Bay. My career included only using computers (not designing them) but they made an interesting hobby. I look forward to your newest videos and again - thanks for the memories...

Oh I realize what this is. It was the first computer I ever used. My high school got one donated to it in early 1980 after a two week computer course that had been taught where students brought in their own PCs (Apple ][s. TRS-80 Model 1, Commodore PETs). The SWTPC I used had 8K of RAM, the cassette interface, a TV/keyboard and "Tiny BASIC" which took about 20 minutes to load from cassette. It was the 6800 that launched my IT career as I spent my free time as a 13/14 year old learning BASIC programming. Our school would then add a TRS-80 Model 1 with floppy drives (which never worked) that same year and a pair of Apple ][+ computers in 1981. I wish I still has for nostalgia purposes if nothing else. Thanks for featuring this.

Your videos are so interesting, engaging and well made! Cheers! Keep up the great work Adrian! Thanks!

Fascinating stuff. I am looking forward to the next episode.

Wow! Absolutely terrific video showing the innards of a great vintage computer! I just loved it right down to your discussion of each card and ICs. Fantastic!

I saved one of these from a similar eWaste fate a year or so ago. I had no idea what it was when I got it. I really like the 6800 design. For me it was like the precursor design to the Apple 1 or 2 because it had addressable expansion slots and a ROM monitor. It’s a proper old computer. Looking forward to you getting this one working.

Thanks for the wonderful video. It's awesome seeing you work on these old machines. I've been following you since the first pc off of craigslist videos. You have come along way.

Great job on this presentation, Adrian. I've got one of these systems on my shelf waiting for restoration. No FDC here but three of the I/O boards that were home built on pegboard. Those molex connectors made homebrewing much easier.

As a sophomore in high school, this was the only computer I (with help from my dad) could afford. I built the kit but didn't have a terminal to talk to it. I bought an old klienschmit field teletype at a surplus auction. With the help of a local computer shop I wrote code to convert ascii to 5 bit baudot and used the old teletype for a year until I could buy a used, non working tv teletype....good times.... It was a great experience for a 15 yr old budding engineer!

I am so intrigued by this machine. This is so different, and yet the same, that it makes be smile. I am on the edge of my seat to see how it works out.

Thanks for video on SWTPC computer. I have heard about the computer, I have never seen actual example, nor a survey of its hardware. Thanks for the video and keep up the good work!

Adrian thank you for saving a fascinating piece of computing history. Your channel is a joy.

Great video! I always enjoy seeing the older "founding father" type machines still working.

Honestly that's a really lovely bit of design, a modern build in a case looking like that would be really great. Understated yet very cool :D

Awesome piece of computer history you have there. Thanks for sharing.

What a fascinating machine. Thank you Adrian for showing us this

Oh, wow! I researched the Imsai, Altair, SWTP and the Polymorphic 88 when I purchased my first computer back in the 70s. I still have the ad folders for each. I wound up getting the Poly88, and I still have it, although I haven't powered it up in years. Great video.

This brings back lots of memories from my late teens which developed my lifelong interest in all things computer.

Boy - this channel brings back great memories. I built my first kit computer sometimes in the 70's. It was a Z80 S100 kit board and a 1K static memory board. I built my own power supply and chassis and got one of the first TV Typewrite kits. It was wonderful - something like 15 lines of 32 characters - but it was a lot better then programming with front panel switches. Over time I upgraded it with 8" floppies and better monitors and I actually used it until the 90's when I gave it to a friends son so he could learn computers. Those were the days!!!

What a great find. I love watching deramp5113's videos. Good to see him getting a shout out. Good luck getting the system up and running.

Love the hard work to fix the 6800! And love the shirt!

First of all, got to mention the sweet 6809 from their later years that LMNC has. Yeah, you have a very early SWTPC. And having a resident monitor standard instead of a front panel was a big innovation that happened in those few years since Altair and IMSAI. (In between was the keypad/7-segment style like the KIM-1 and H-8.) I guess ROM chips for a monitor program finally became affordable or something. Note that 1977 was the dawn of the Atari 2600, which made mask ROM chips a big business. That floppy controller is enormous. I have one that I found on a 30-pin card, where some fool tried to fix it by piggyback stacking chips. As for the price, the original TRS-80 Model 1 4K was $599, also in 1977. This was a time when even a single year brought major advancements in bang-for-the-buck. I was living in San Antonio since 1979, but never had any idea to visit them back in the day. I'm kind of sad that I didn't, but I didn't even have a driver's license until 1981 or so, and I was firmly in the Radio Shack camp the whole time. By the time I realized they were there, they were gone. Apparently the final two boxes of SWTPC repair parts (chips and other small parts) ended up at the 10bitworks hackerspace a few years back (I was there the day they came in), but with how hackerspaces are about "junk" taking up space, I have no idea if they still have them.

I've got a couple of the SWTPc 6809 chassis and a box full of cards. These were made around 1981, and I know that SS-50/SS-30 bus machines were in use into the late '80s, especially ones from GIMIX. The 6809 machines could run the same multitasking, multi-user OS-9 operating system that ran (as an option) on the Tandy CoCo line. With all those expansion (slots? not really slots) you could have quite a few terminals, and a Level II OS-9 system running at 2MHz, with up to 1M of RAM and a dynamic address translator could support a surprising number of users. One fascinating card I have among my collection is a board for the SS-30 bus that contains a National Semiconductor calculator chip, which serves as a math coprocessor for the CPU. The (D)OS most commonly used on the 6800 was called FLEX, which was essentially the 6800's answer to CP/M. There was also a version of FLEX for the 6809, as well as UNIFLEX, which, I believe, was an attempt to make a multitasking UNIX-like version of FLEX. I don't think that one saw much use though, since OS-9 did the job it was meant to do better, and was endorsed by Motorola. The source code to UNIFLEX is available on the Internet. There are modern SS-50/SS-30 reproduction cards, and Corsham in the UK sells high capacity static RAM boards and CF card 'hard drive' interfaces. One thing to be careful of on these systems is that forest of pins. It's extremely easy to consume fuses on that backplane by bridging between pins with a screwdriver or some other metal tool. Ask me how I know. A great resources for these machines is the magazine "'68 Micro Journal". Scans can be found on Internet Archive.

What an awesome walk through history this was... thanks!

SWTPC advertised heavily in Popular Electronics magazine in the 1974-1976 time frame. I remember seeing their ads for this kit.

Thanks for sharing! I haven't seen one of those, (plus the Imsai & Altair) in decades! These were some of the first boxes I learned to program on other than mainframes, and drew me into my career.

I'm very glad to see a SWTPC 6800 on your channel Adrian! I'm a keen Motorola 6800 and SWTPC 6800 hobbyist. It was very common to have both the MP-C and MP-S cards in the same machine. The MP-S is faster and better but for full MIKBUG and software compatibility the MP-C card is needed. Eventually SWTPC released their own SWTBUG that used the MP-S card natively but most users kept the MP-C for compatibility and to use as an extra serial port. The Motorola Engineering Note 100 is a mandatory read that describes the 6830 MIKBUG ROM and the associated hardware that is the very base of the SWTPC 6800. The BFD-68 was made specifically for the DOS-68 system. DOS-68 was a competitor to FLEX but never really took off. FLEX is compatible with the 1771 controller chip used on the BFD-68 card but it may need a custom driver. I would not be surprised if such a driver already exists if technically possible but writing a new FLEX driver is quite trivial as long the hardware specs are known. Actually it's possible to wire up a compact flash card in 8-bit ATA mode directly to the SS-30 bus as a nice FLEX driver writing exercise :) Even though I have never owned a SWTPC 6800 I have built several compatible systems. My latest SWTPC 6800 compatible(-ish) incarnation, "MC3", is based on the souped up 6303 CPU.

Good find. Those were neat machines, but the 6809 version was even better.

Tremendous video, thank you for all your hard work. These computers are part of history, they should not be forgotten. Remember that Android phone you are holding came from this.

This stuff is super interesting. Thanks for putting out the video

Ah, the good old days! I have the 6809 model - not just a CPU upgrade; the enclosure is a newer design, and I think there were several other differences. It's in storage these past many years, after having been my primary computer in college. If memory serves, I got it with 8K of SRAM, then wire-wrapped a 48K DRAM board. Got the standard dual floppies, plus a kludged-on double-the-tracks drive. I should dig it out and refresh my memory on what else is in that box. I have a vague recollection of running a wire from the power supply to somewhere-or-other to get a 60 Hz interrupt.

Never had one of these as they were way before my time. But my father was an audio junkie back in the day and he bought and built a couple of the SWTPC power amps he got from a mail order kit. I still have them and they still work!

I worked with this computer for a number of years. it had 2 floppy drives and a printer that we used to print labels of pay-slips envelopes. I know 2 people that had their own systems. I will ask them if they still have documentation etc

Very cool. This whole series has been educational about the computers present during my childhood. I was too young to understand what they were but saw them at my parents workplaces and later in computer labs.

I really enjoyed this video! In Sydney there was a computer club called MEGS - Microcomputer Enthusiasts' Group Sydney, which was the first computer club in Australia. I joined it while I was at school in the 1970's. So much was above my head but it led to so many things for me - two jobs. Cheers

Mid to late '70's, those were the days 🙂 A friend of mine built one of these SWTP's. . I made a home-brew TMS9900 from scratch. That was a good learning experience for both hardware and software.

Amazing machine, never heard of it, can't wait for part 2

One of the things I love about this channel (and it’s sister ADB2) is the mix of content. A lot of what’s covered is stuff I know really well, such as C=64’s, Amiga’s, ST’s, Mac’s, 80’s PC’s, etc.. Often I use stuff covered here as a gut-check for some project I’m about to undertake. Then there’s the stuff I wish I had, and might someday try to get my hands on (like the TRS-80 Model 2), which is a really fun series (with a great conclusion). And then there’s stuff like this: amazing artifact that I want to watch Adrien work on, but I wouldn’t ever feel comfortable messing with myself (too rare, too early and probably too expensive / difficult for me to find). The one recurring question I have is: where does one store all these computers? I don’t have anything close to the number of machines covered on this channel, and I also have a basement office / workshop, but have long ago run out of space for the limited stuff I have.

Another great video, I hope you are doing well Adrian

What a trip! Thanks for this video.

These early computers are fascinating. Great topic, great videos.

So excited to see what using one of these is like. Completely flew under my radar.

This is fascinating indeed! Like you, my knowledge stretches back to the PET, but anything earlier than that I've no clue about. Doesn't make it any less interesting of course, quite the opposite! Looking forwards to the next video, hopefully you can get it working. :)

During the time SWTP was in business I bought several of their kits, still have two in use. I wasn't aware they offered a computer. Interesting, look forward to seeing it in operation.

Not sure how you make each post "routinely brilliant" but thank you!

Thanks for the awesome video. Wrote my first programs in mbasic on the Altair so have a soft spot for these old computers. Recently watched some fascinating oral histories related to the development of the silicon used in a lot of these systems back in the day. Now I’m thinking about how I can use some modern stuff to load CPM for the Altair yep I can see it already S100PI. Thanks Man!

This computer is fascinating, I love the deep look at the hardware. This 6800 really seems like a playground for a nerd like me.

Back in the late 70's, my father (who I just e-mailed the link to this video) had one of these! I don't remember the major details about it (I was a kid at the time -- just recently in elementary school), but I do remember he used it with a teletype keyboard/printer. And I DO remember the separate disk drive for it (I think it was the same maker, but I only remember it having two drives rather than three).

That is a total gem. I never heard of them back them (I probably saw an ad for them), but was hooked as soon as i saw the Altair on the Popular Mechanics cover. I held out for the Vic-20 and when it hit the magazine pages, with a full keyboard, color, and graphic character set, I was ready to throw money at them, and I did. Not easy as a 14 year old kid to come up with $450 for the computer and datasette (saving Christmas and Birthday money - I had no job - so it took me quite a while to save up). People don't grasp today how unbelievably weighty the keyboard factored into your purchasing decision of which computer to buy. It seems laughable now when you can plug any keyboard into any PC, but back then when you were looking at Sinclair and Atari membrane keyboards versus say a C=64, yeah, you see, the keyboard was the killer feature. You wanted something you could pound out tons of programs on, and then be able to save them and retrieve them reliably. Because you didn't have money left to buy any software - there was no software - you were going to have to write it all your own. A lot of these are stored in temperature uncontroleld barns or sheds as junk. I use to say comptuers came to me to die and I got them all in the end. I've got a dinosaur elephant graveyard of them, all neglected. Back in the day I would of killed for any one of them. Now I can't stand to even look at or touch the wretched old things, the memories are too painful. A Commodore 128 or Mac Plus back then would of been a wonderland to me and there wouldn't of been any coming back from inside those machines. My granparents gave me a C-64 out of the blue next xmas, and after a hiatus... my next computer was a Mac SE. From the Mac SE I went to a 386 and a Performa 476, and from there it exploded ito bringing home comptuers by the pickup truck load. I used the SE to write programs to earn money to buy the 476, and then used the 476 to ask universities and businesses for all their junk computers. Sprinboard, springboard... like jumping stones in a creek.. to computer empire hog heaven :-) Halcyon days back in the roaring 90's... for a perpeetually unemployed kid.. I was living my version of the Steve Jobs dream. 40 years before that blad 8bit guy ever came along. LinusTechTips had nothing on me. In fact, if I hadn't changed directions, I would of ended up that 8 bit guy, a sad endinge.. but I let go of these machines finally, and blazed a new trail always upward and forward. It would be nice if I had a museum to put all this old hardware in... for dispaly.. I'd never have the time to refurbish any of it.

Even back in the 70s there was an Intel vs Motorola vs RCA community. The S100 Buss was predominantly Intel 8080, 8085 and Zilog Z80 based, whereas the SS50 and non-S100 systems were predominantly Motorola and non Intel based. Of course each Chip Company had their own proprietary Development Systems, varying from bare-board SBCs to fully assembled Systems with Professional Cases, Serial Terminals/Monitors, Dual 8" Floppy drives, DB25 Serial Ports, DB25 Parallel Printer Ports (Centronics Interface), and In-Circuit-Emulators (ICE). The Intel iDS was one such offering which was used to develop Software and Hardware for Intel 80xx 8-bit Processors and Microcontrollers using the Intel Development OS, Assemblers Compilers and launguages such as BASIC and PL/M. It also ran Digital Research's CPM-80 and many CPM-80 supported softwares such as WordStar and Microsoft Basic. There was a huge offering of SBCs, Built Systems, and Ancillary Boards and Peripherals in the late 70s and early 80s.

All I remember of SWTP was when a work buddy brought one over to get it working, I was shocked at how long the 6800 BASIC interpreter took to boot compared to my 6502 KIM-1 machine.

Perfect video to watch while working on Arduino code for my first soldered breadboard computer!

I actually have one of these amazing machines. I got it just last August with 24K of ram and the cassette interface. One note on the ROM and the terminal interface. You have the later ROM called SWTBUG, switch can run the terminal at 1200 baud. I used it on my VT320 terminal and learned a bit of 6800 assembly on it and did things like play games using the 8K BASIC. I hope to find a floppy controller that can hook up to my dual 8 inch shugart floppy drive enclosure that I use with my IMSAI. Once I find that I can run Flex, which is a really interesting OS, basically the CP/M of the 6800 world. Of course the next step for me is to finish the Teletype project, which is torn into 1000 pieces atm.

Very interesting. Though I'm familiar with the Altair 8800, I don't think I've heard of this computer. I'm always impressed how robust the integrated circuit boards from the 70's were. I rebuilt a late 70's Atari 800 to new like condition about 7 years ago and the thing was built like a tank. Made it very easy to work on.

Your video was terrific, Adrian! Thank you. Roger in Wisconsin

The December 1975 issue of Byte has an extensive article on the SWTPC 6800. Interface Age was another great magazine during that era. SWTPC was all over back then - it was on the cover of the September 1976 issue of Interface Age.

deramp is a great channel, learned so much about the early days of PCs from him.

Wow, did this bring back some memories. Immediately following high school I ended up working for a small business that sold these computers. I was hired to write software (in BASIC) on one of them. It was hooked up to an ADM-3A terminal for input an had the same SSB card as in yours. It also had two stand alone floppy drives to install the BASIC interpreter software and the other to save the software I wrote. It remember that after loading the BASIC on the computer, I had to poke into a certain memory location to start the BASIC program so I could write my program. It's a shame that you didn't put this video out 6 months ago, because I could have sent you all the schematics, manuals, and sales literature that was available for them as of 1977-78. Unfortunately, my wife came across my old 3" wide binder on the shelf in our home and asked me why I was still holding on to it for over 40 years. So I caved in and threw it all away. Oh well...

This was the very first microprocessor system I was introduced to in 1978 - in my second year at university, which had a set of them for students to learn 6800 assembly language on.

@Look Mum No Computer picked up an SWTP machine a while ago to fool around with, and it's fascinating for the obscurity alone. Nice find!

That was such an exciting time of computers. I was not quite a teen when the SWTPC 6800 computer came out, but I used to drool over ads for it in magazines of the day. I could never afford one on my allowance, but sure wanted one. I eventually was able to get a COSMAC ELF single board kit as my first computer. I learned so much from it!

I really like the look of it!!!

Nice find.

Love the look of these old PCBs.

Adrian, it looks like you could recreate those front and rear trim pieces from some small aluminum angle or U-channel. Cut a v-shaped notch and carefully bend the 90° corners, or cut them on a hobby sized miter box.

Adrian, in the old Byte magazines (which everybody read way back when), the SWTPC was advertised all the time. They were still just for experimenters. It wasn't until the Apple II and the TRS-80 that it moved from experimenters to guys who could just tinker if they had a little bit of skills.

Awesome to see a computer with no tiny Surface-mount technology (SMT)'s.

Still have my SWTPC 6800 system & documentation which I built as a senior in college (like 1977). Have a 4K plus a 16K memory board, several extra interface cards (serial & parallel), cassette interface, and the CT-1024 terminal with the matching SWTPC monitor. Remember buying the 16K memory board on a trip to Boston, MA ... it cost me around $625 which was more than the kit cost. Actually used it to acquire data (SPEX laser Raman spectrometer) as part of my master's thesis in 1979 ... very few "computerized" spectrometers in those days!! Guess I should see if mine still works ... look forward to you next SWTPC 6800 video!!

What a cool time period. I remember being interested in computers at this time and wanting to write software but being a kid I couldn't remotely come close to affording one.

Very cool. Now I can see that the PET power supply situation wasn’t uncommon at the time! Neat that it’s a pseudo-standard of the time with some clones as well. Love seeing the “floppy disc” in some of those promotional materiel by the way, pre disc/disk codification is always interesting to me. That triple drive chassis looks like a brick!

The 6800/6809 were "relatively cheap", but keep in mind the 6502 came into being and sold millions because it was less expensive than those cpus. It probably related to complexity and "yield". Excellent video though.

I worked with a 6809 version, Gimix. It ran OS/9 a Linux clone. It was multi-user and multi-tasking. It ran rings around the first PC.

The SWTPC's 6800 was loved by my vocational electronics class in high school. We built one. In 1976 our instructor had gotten one to build as a class project and it set several of us on our career paths. I am still working at a network engineer today nearly 50 years later!

What I find interesting is that much of the technology used in the SWT 6800 was later found and used in Commodore machines...at least there is some shared heritage. Fascinating stuff!

I bought my SWTPC in late 1977. Parts started arriving in 1978. By September I had a running machine. It was purchased with 8k of memory. I got 4K Basic on a floppy ROM. I also made the CT64 Terminal. Around 1980, I got floppy disks for it with the DC3 driver board. As a HAM, I got on the internet around 1984. At the time the ARRL had a class A to its self. One of the local HAMs gave me my own subnet. I got up and running on AX.25. I found a way to make AX.25 unreliable and was able to run Telnet and FTP. On the 2 meter band through my 2 meter radio and a MFJ-1278 Terminal node controller I was up and running. The last thing I did with it was to design and build a 48K memory card. It still works. I also got the GT6144 graphics terminal and an Atari 2600 joystick through a parallel port. I wrote a crude PAC-MAN program. My first checkers program was written in the late 1970's. It used the inhex 2 character routine to enter moves.

Thanks for all the great work and history of this machine.

I think it is stunning in its simplicity.

Glad to see you covering some older computers from the mid to late 70s. Maybe you can do an S-100 system at some point

My first computer build was a SWTPC 6800. Although I used audio cassette with the AC-30 to store data and programs, I later added an 8” floppy drive offered by SWTPC. The floppy drive used a parallel card. I bought a Xerox daisy wheel typewriter with an parallel interface to use as a terminal . Later I bought an ADM 3A CRT terminal and upgraded the RAM to 32K. I still have the main unit and AC-30 stored in the attic along with the documentation. I built a system based on the Motorola 6800 because I had worked at Motorola when the 6800 was being developed. The 6800 team recruited a colleague of mine to write a cross assembler for the 6800 that ran on the DEC PDP/11. The 6800 team leader was Chuck Peddle who left Motorola for MOS Technology where he developed the 6502 chip that was used in the Apple II and the Commodore PET.

Adrian, thanks for reminding me of my misspent youth. The SWTPC 6800 is a great computer but it suffered one major problem: Molex disease. To keep costs down they used tin plated connectors that would tarnish, leading to bad connections. Third parties offered gold plated replacement connectors. The Altair S100 and SWTPC SS50 weren't the only 8 bit busses of the mid 70s. Motorola had it's Sherman tank of a 6800 development system called the EXORciser. It sported a bus based on standard 86 pin .156" pitch edge connectors. Up through the 6809 era there were third party boards that used the bus. The EXORciser was an expensive system, especially with 8" floppies, teletype console and/or $1000 dumb terminal. A brilliant move on Motorola's part was to sell the MIKBUG/MINIBUG program housed in a 6830 ROM. This allowed SWTPC to develop its computer sans switches and lights and yet have serial I/O and debug tools. All without having to write firmware themselves. I seem to remember that you could buy the MIKBUG chip alone. While the EXORciser was aimed at industry, Motorola did not forget the amateur. In 1976 hey used EXORciser's bus on the MEK6800D2 kit. ( I could never watch Star Wars without being reminded of my beloved D2) At $300 it was a true single board computer, with 640 bytes RAM, serial communication chip, and It's own monitor/debug ROM: JBUG. On the top edge there were 2 50 pin ribbon cable compatible edge connectors, each wired to a 6820 16 bit parallel interface chip. The remaining 10 sq. in. of the board was devoted to a user prototyping area. The kit, came with a ribbon cable that lead to a PCB with 6 seven segment displays, a hex keypad, 8 function keys and a cassette interface for mass storage. I spent countless hours banging and debugging hand assembled code (branch calculations anyone?) into that keyboard. A bit later Motorola developed a video interface chip, the 6847 that made it easy, with an RF module, to display data, in color, on a standard TV. New chip, new development kit, the MIcro Chroma 68. It came with, "The new "bug" from Motorola, TV bug 1.2" The board also had the familiar 86 pin edge connector that I assume, but can't confirm was configured as an EXORciser bus. I never owned a Micro Chroma 68 but I used the 6847 and cloned TV bug ROMs in my own hand wired systems.

A couple of years ago I did a compiler backend for the 6303, which is a slightly improved 6800. It's a nice CPU. Not enough registers, but very pleasant to work with; it has indexing like the 6502 but some sixteen-bit operations like the 8080, and very dense code. It lived on for years as an embeddable microcontroller. Unfortunately there was a much smaller software ecosystem for the 6800 than there was for the 8080; the only OS I've seen for it was FLEX, which I haven't been able to find a copy of.

OMG OMG OMG I had to stop what i was doing and jump to your video when i saw the picture Adrian! I soooooo wanted one of these SWTPC computers (did nobody else call them "sweet peas"?) when i was a kid. I also remember clones of THIS machine, Smoke Signal Broadcasting had a "Chieftan" that also used MIKBUG or SWTBUG, if i recall. Now I have my popcorn and gummis ready; let's make it freaking WORK! Wheeeeeeee!!!!

This is great, my final year project for my engineering degree was writing assembly for the Motorola 6800. My tutor was leading a research project to develop a system for testing the hearing of neonates. This was in 1982, 40 years ago but in some ways it seems like yesterday.