One of the first printers for a home computer: the SWTPC PR40 

First!

I'll admit, the noise and sign of that machine running is a real beauty.

Back in the day I worked for Simplex (now part of johnson controls). originally a time clock company that became the largest fire alarm company. the first generations of advanced alarms would have those printers built into them to record event history

Very cool! Also, "once upon a time when I had my ribbon re-manufacturing business..." dang, that was a totally reasonable thing back in the day and now it feels like, well, like I must be very old to remember a time like that!

Love this sort of "analog" technology right at the birth of what we consider "computing" today. Incredible engineering and ingenuity that went into these machines.

Seeing it in action was WELL worth the wait. I've never even HEARD of this model of printer before, much less seen one or even seen one IN ACTION before, so this is truly a case of me being introduced to some "new-old" tech and I CANNOT thank you enough! Don't lose sight of this niche you've found for yourself. I've been seeing way too many "RU-vid museum" channels slowly creep away from showcasing old, defunct tech that most have never heard of over to reviewing more modern "retro" tech that's filling shelves instead of the bargain bins they all truly belong in (looking at you, Crosley Cruiser 😒😣😵). Tech history has now become every bit as rich and deep as any other and we NEED more of these RU-vid museums putting out tech history in a way which is most suited to it...online, in the modern tech environment these devices all helped to ultimately build. Keep bringing us back in time, you're making it quite the awesome ride! 👍☺️😁♥️

The printer SWTPC used to build this was made in Riverton Wyoming by LRC, a model 7040 ticket printer. At the time this was an OEM printer sold with no electronics mainly for cash registers, casino and lottery ticket printers. LRC was purchased in 1980 by Eaton corporation, now it's remnant is Pertech still in business. I went to work for the company in 1980 as a test equipment engineer and built Z80 S100 based computer diagnostic, production and life testing computers. I still have parts and a working improved version of this printer designed an built by LRC using the 7040 printer.

Saw this advertised in a 1976 Popular Electronics magazine and wondered how it operated. Many thanks!

A few notes that didn't make the video: I ended up cutting the DB25 off and just plugging the wires directly into the molex header on the MP-LA. Totally forgot to mention that. Also, I ended up moving the MP-LA to Slot 2 during testing, so that's why the address I entered near the end is hex 8008.

That 5x7 character matrix is still used today on many small LCDs!

In April 1975 the Australian EDUC-8 home computer came out with a printer, the Philips 60SR dot matrix unit (they called it a 'mosaic printer') which had a 5x7 character alphanumeric matrix and printed on a roll of paper just like the one featured here. The EDUC-8 was serialised in Electronics Australia magazine from August 1974 through to August 1975.

I wasn't alive for most of these machines but they are so interesting. Love the channel!

Hey, I STILL have a bad haircut! Just a different bad haircut than in '76. :) I helped build one of these when they were new. I was just 18, but my friend & mentor bought one of these. As someone who was reading all the computer magazines every month back then, I agree that this was the first printer designed for the computer hobbyist market. When Bob got sick of printing on cash register paper a couple of years later, he upgraded to a surplus commercial Centronics 101...which I got to help him carry upstairs. Yeah 150 lbs sounds about right! That monster only printed in one direction, so returning the carriage to the left side was dead time when the printer wasn't productive. Well, they wanted to minimize that, so the carriage return on this dinosaur was like firing the printhead out of a cannon. It then slammed into a BIG shock absorber on the left side, and shook their whole house when it was printing. Ah, the good old days. :) Later, he also acquired a "Friden Flexowriter", a direct competitor of the Teletype machine you showed, I believe. I don't recall what interface the Friden used, but it sure wasn't RS-232 ASCII. Maybe BAUDOT encoding? Bob designed and built a conversion board that involved lots of reed relays. I can't recall the model but it looked like the Friden 2200 series. Nice channel. :) Subscribed.

That thing really spit the characters out. Impressive speed for the era.

Fascinating! I'm quite amazed at how fast it is. It would likely have saved a fair bit of time (and paper) for my Commodore 64 program listings. I can also imagine seeing one of those in an upmarket store, with the comment "If you don't pay, we'll turn this thing round and switch it on!"

It's amazing how far things came in just four years with the Epson MX-80.

That is for sure the coolest thing I have seen on RU-vid in years.... Now lets 3D print one....

You talk about the look of this printer, and I see parallels in the looks of a lot of the 3D printers on the market.

Remember building it back then. There was a company that did a vacuum form top that protected the top. Love the SWTP!

This reminds me that decent printers were ridiculously expensive until Japanese dot-matrix models with 'Near-Letter-Quality' (double-pass) output became affordable (mid-1980's?). Before then, letter-quality printers were $1500 and up, while dot-matrix printers cost less, but had crude output. I remember (late 1970's-early 1980's) when converting castoff IBM Selectric typewriters for serial or parallel output was a thing; but such machines were very slow and had to be realigned constantly -- and they would still set you back several hundred dollars. (One can treble or quadruple the prices involved at the time to get the cost in today's currency.) I enjoy your channel, which fills a gap in coverage by most other retro channels, which are PC/Commodore/Apple-oriented and seem to dwell mostly in the 1980's and 90's. I love hearing about stuff from the initial 8-bit wave, including CP/M. Thank you.

Back in the day I worked in a telephone exchange for the Air Force. They used teletype machines for communications hard copy. After my tour of duty I bought a used teletype machine and connected it to my TRS-80 Model 1 computer. I then wrote a short translation program to convert the asci 8 bit upper case and lower case to 5 bit upper case Baudet code, slowed the data speed to the teletype machine, and added a timing delay and current loop circuit to match the teletype machine. It was painfully slow to print anything, but was better than scrolling through a tiny screen full of code looking for a bug. Having the entire code to search through made life a lot easier.

I remember the day when printer manufacturers discovered *bidirectional* printing ! It took another year or two before they garnered enough mechanical precision to get adjacent lines aligned !

Seeing that improbable printer come to life -- definitely wish there was a way to give a standing ovation to a video

That PCB looks absolutely gorgeous. How something like this could last as long as it has without outright oxidizing is a miracle.

What a great piece of content you've provided everyone with. I recently became interested in SWTPC after years of forgetting about them. My Dad had some of their audio products, two of their mono amps, and something else I can't remember what it did, some kind of testing equipment, I think. I'd like to get the SWTPC amps and kind of recreate my dads old system. He never had any of the computers I don't think, I just remember the amps mostly. I think they were called Tigers.

I have fond memories of this printer, which had 40 bytes of line buffer memory, and the printer mechanism itself was a cash register printer. You could send up to 40 characters to it followed by a carriage return, and the printers electronics would convert the bytes in memory to a character using its font memory in EPROM, and discrete electronics (no microprocessor used). At that time I had a friend who self published a magazine about commodore computers, and especially the PET. So he wanted to write an article about using this printer with a commodore PET, and he asked me to check his built as he wasn't a hardware person. So I obliged him and checked what he had done. I checked if the IC's were soldered correctly not 180 degrees rotated, and all was well, his solderjob looked okay, and he had not soldered in the electrolytic capacitors in reverse, I saw not other errors, so I cautiously gave my go ahead. My friend powered up the printer while he was looking at the PCB to see if anything started smoking. The moment he turned the printer on the large electrolytic capacitors in the power supply exploded right into his face, and there was brown and silver paper confetti everywhere. when he had recovered from the fright and had washed his face thoroughly, I checked if I could find out what had gone wrong, not the polarity of the caps, I had checked that. Then I saw the cause, he had reversed the types of molex connectors, and had used male connectors where it should have been female connectors , and female where is should have been male ones, this had swapped out the order of the wiring, resulting in reversing the input voltages. I later heard that eventually, after replacing the electrolytic capacitors, and swapping the molex connectors, and replacing a blown fuse he got the printer to work.

never thought I'd see a pleasing video of a desktop printes

I no nothing about what’s going on in this video, but I loved every bit of it, I’m glad you got it working

very impressed with this printer resurrection, reminds me of when i had to create a driver so my amiga 500 could print to the 9 pin dot matrix printer i had. amazingly fun to watch !

I laughed so hard when the warning on that printer said do not operate more than a minute or it will catch on fire 😂

That drive mechanism is genius!

I rejuvenate my old cloth printer ribbons with "endorsing ink"... it's OK (not great but OK) This looks absolutely wonderful.... SWTP really did understand hobbyist aesthetics!! Back in those days, I was just a kid and making imaginary computer printouts on a portable typewriter and paper rolls intended for cash registers (there was an office supplies shop in our street, that had a wonderful dustbin)... it's great to see just how accurate my "simulations" were.

Ahh, good times... This brings back the memory of my first printer - Seikosha MPS-801 with serial interface for Commodore computer. The only slight issue was that i had the Spectrum, without any interface whatsoever. So I made my own, using Z80-PIO, If memory serves. BTW, MPS-801used so called "uni hammer" head, so instead of 7 pins, it has one long vertical hammer, and below the paper was long rotating star shaped prism, so printing was performed "pixel by pixel", compared to normal dot matrix "row by row". No wonder that, at 50 CPS, it sounded like Stihl chain saw... Compared to that, SWTPC PR40 printing technology look quite modern, especially considering it was about 10 years before MPS801 :-)

Wow, SWTPC really did stick to that hobbyist look all the way! I agree that the solenoid array on the print head does look rather threatening, and it would probably work well if filmed close-up as a sort of model of a weapon of some kind in a sci-fi movie. ;-) Thanks for showing it to us in operation! BTW, I loved the introduction in the video, and especially all the silly little animations, hehe.

It was so satisfying to see that line of text coming out so fantastically clear.

What an awesome piece of equipment. Love the appearance and the sound it makes.

What a cool printer. I like the mechanical guts hanging out.

That was awesome!!!! And some real patience when troubleshooting Well Done getting this wicked bit of kit all fired up and sharing!

Great video! Nice to see another marvel of retro technology.

So cool you got this going! The output is quite good!

SWTPc's 8k Basic & up would print to the PR-40 with a PRINT #7 command or a LIST #7 command. Flex's default P,DIR would also print to the PR-40. Aside from the PR-40, any printer you could connect to your system co$t more than everything else! I have fond memories of them. I even had an article printed in "Doctor Dobb's Journal" that was printed on a PR-40 and was how to use the PR-40 with SWTPc 4K Basic.

Top-notch content, as always. Bravo!

It's so crazy seeing a whole computer system with no solder mask.

I just watched this video for about the 3rd or 4th time and just now caught the KOA reference when you mentioned the cost of the printer being about a month's rent! I'll be snickering all evening. I love the mistyque SWTP products still have. My buddies and I always coveted them , when we were in Middle School -- When we weren't drooling over the WD Pascal Microengine ads.

That is a wonderful sound:)) I still have my first printer from 1982, it was very loud. I remember writing a printer driver for it to print APL characters from a PC in just two evenings.

Very satisfying to see this work, amazing. Incredible that you got this working.🌷

This is awesome - I never knew this animal existed. I built a SWTPC stereo preamp in about 1980. As you described this printer as an "affordable option," that is similar to the preamp. It worked but was not a great piece. If I had more money I would have bought a Dynaco...

I was around in those days. We got our first computer in '77. The TRS-80. A year later, we got whatever printer Radio Shack offered for it. It was a dot matrix, DMP 100 for about $600 US.

I love your animation style. Please keep up the awesome work.

Still better build quality than my old Sinclair ZX Printer. Dunno if you've ever encountered one, but [musical jingle] "if you really really loved the keyboard on the ZX81 for its ergonomics, longevity and pain free use, then you'd love the Sinclair ZX Printer" [musical jingle coda] :) I found parts of mine the other year in a box from my folks' attic. Sadly 12 year-old me apparently disassembled things in much the same way that Jonny 5 disassembles caterpillars. Tho in hindsight this was probably for the best.

bringing one of those to a tattoo convention could start the revolution of seven color rasterized body art.

I'm impressed by its speed

Lmao that thing's faster than the dot matrix we had in the 90s!

Kind of want to find one of these and get it working with my Commodore PET 2001-32N just for fun. Cool piece of teck and nice to see it working.

Look at that 'little' printer go!!!!!

So what if it takes up a wall of space. Seeing the history of computer innovation as addons physically is amazing to me.

That is the coolest, man! You rock!

The first idea I had when seeing that printhead was if you could use it for tattoos :D

My first printer (1979) made the PR40 look like a world class printer. It had a 64 character horizontal drum print head. It printed okay but the horizontal feed mechanism was, at beast, flaky. It would often skip a character or write over the last one. Still, it was so cook to see my TRS-80 actually printing!

Awesome job. It sounds fantastic. :)

That printer sounds like a cash register printer circa 1993 or so. My local grocery store called “County Market” had receipt printers like that until right around 2003 ish.

Impressive troubleshooting and great information! My first printer was an IDS Paper Tiger 440, which didn't seem much further along technically than this. It was a beast, but I had so much fun using it with my Exidy Sorcerer. It even had "graphics"!

That's a cool mechanism.

I know them from back in my SAP AG days when they were still working on Gas station automation and used them here in the US in the mid-late 70's. LRC Inc made printers primarily for calc's and adding machines back in those days but they were available for other "custom" applications like an SAP implementation or something like this...

Fascinating!

Fantastic video!

. thanks for the traveler story. .

Dude! A-W-S-O-M-E! Your sheer dedication, soothing piano music and (first and foremost) this old stuff gets me fired up! I just love this stuff. I just found Your channel and am pretty stoked about it because You lack the catering to the crowd like so many channels do when they reach a certain level of subscribers to keep the money coming. So many once good niche channels outgrew themselves, they become so big that if they feature something that same day Ebay goes up 300%... Please keep at it like this- I enjoyed this especially because of the printhead. I fixed up an old Epson LQ I needed for an oscilloscope attachment with one main attraction: to hardcopy the screen content. Had to cobble together a cable but got it working as intended. Sweet succsess but it came with black fingers as I was keen to refurbish/re ink the old ribbon that came with the printer because it was well before its due date. You had a company that did that? You must still remember there were machines that did that for the home gamer. I´d love to search for one but I don´t even know how they were called. Matters worse: I live in Europe. What kind of ink You would suggest as normal inkjet ink dries up too quick. I´d love to get in touch to get some advise as I just need the right ink. Thank You, Buddy!

Awesome! Thanks for sharing. 😉👌🏻

SO AWESOME.

Very cool!

Amazing. Looks like equipment used by the ministry of information in the movie Brazil

Some searching shows that LRC Inc. was issued a few patents on the printing mechanism. Based upon the patents the original target was printing calculators.

With the disclaimer that this is from vague memory of first-hand memory from my 20s when I'm well into my 40s now and my memory isn't getting any better... I recognize LRC, Inc. as a name from my time repairing old stuff from Big Blue. I don't know the providence of *this specific model* - but ones like it were used in early model cash registers, what would be the progenitor to the SurePOS systems IBM sells to this day - the LRC printer component part anyways. These were essentially terminals - there would be a SurePOS "master" that was a computer running a very early operating system - CP/M or AIX depending on age though it would have been CP/M back then, usually held in a cash office or similar secure accounting space, and then SurePOS registers. They were a little smarter than dumb terminals, since they would be attached to a printer and cash drawer the terminal would have to interface with, but not by much. The LRC component was the printer only, as the chips to control it would be either on the controller for an economy system where everything printed in the cash office, or on the terminal if they were at the register. The former was more common until the personal computer revolution began. These were largely used in many banks, and modernized versions of these are still used in some banks back offices to this day, such as TD (or they still did some six years ago when I finally got out of doing this as anything but a hobby - might have changed in the intervening time). From what I was told when I was trying to back-engineer these for lack of documentation, LRC was a second source for IBM, but I am not sure about that because I never saw anything other than LRCs with these early systems. It's possible they were a primary source but got relegated to secondary source status when more providers came around. But, even so, it was never an exclusive thing back then - the market was too small for exclusivity to be sustainable (and indeed many companies had problems even without it). So it doesn't surprise me to see Southwest using a component that was largely-proven by Big Blue to try to get to worth with their attempts at personal computers. It would be a while before that really took off, I guess the SWTPC 6800 was before its time in that regard. I just wanted to finish this long questionably-informative ramble with saying I really appreciate seeing you getting these old systems working again - they're basically historical artefacts now, and pretty much everything about our current society owes much to these early forebears. It's more than just a nostalgia trip: understanding how primitive computers works is very informative to the underpinnings of our current computers.

at the end, I’m like great, put the cover on it! :) A bit before my time where I’d started with tape and a commodore 801 printer

That looks like a prototype for the dot matrix printers that came out in the late 70's early 80's

..that 70's yellowing distressed torn printer fragment is more precious 💞 than Heisenberg's stego GPS LAT LONG sweepstake receipt magged to Skylar's kitchen refer.

The printhead looks very much like one for a solid-state teletype.

23:58 Isn't that a Steely Dan song? "Until my chip comes in, I live byte by byte!"

Reminds me of the steampunk video terminals in the "Brazil" movie.

Amazing

This printer mechanism was used in the Atari 820 printer. Edit: Actually not quite. The Atari 820 was an LRC/Eaton 7000 and this is a 7040.

I wish there were some kind of mini ribbon punch maker and readers.

I had a Superscope tape recorder! Mine was a POS! I eventually replaced it with one form Radio Shack (a CCR81) which I later replaced with a Grundig DCR 001, which I still have and it's an order of magnitude better than either of the others I had.

Looks like a modern 3d primer!!! Well, as Heath-Robinson as anyways...

You should have tried wiring up a bunch of switches to place 0 or 1 on each of the inputs as appropriate, a push-to-make switch to the strobe and perhaps an LED on the busy line. Then you could have sent one character at a time to the printer by setting the desired ASCII code on the data inputs and flicking the strobe switch, finishing with 0001101 for a carriage return .....

👍🥃☕🍷🍺🏆👍 You have incredible collection of old equipment! Good that this printer works! Old devices are rather easy to repair but the biggest challenge is the lack of components. I'm also trying to save life of retro devices and have sth about that on YT as well.

Ah, the joys of MIKBUG...

You could take that print by head, replace the piston rods with needles and be able to type on tattoos!!!!! 🤣

2:25 I think the manual specifies: *Do not echo character 0x0A or 0x0C > LPT, after midnight* ;)

OMG, I had actually used the teletype that you showed (I think). It operated at 50 or 60 baud.

My dad bought one of these for his Apple II. ISTR that he paid ~$150 for it used, plus the cost of a parallel port which I think cost more than the printer.

I wonder if people in the 1970s said just use a typewriter buddy.

In theory, you should be able to hook up an old dumb terminal's AUX (as opposed to RS232) port to that, and drive it..

What is the jazz piece that's playing in the background? Nice volume btw, some youtubers put their background music WAY too loud.

Didn't Radio Shack also sell a feeble four inch printer in the late 70s? I sort of remember that it required special impact paper because it didn't have a ribbon.

There's actually a couple of those early 70s production printers hanging out at a local junk store I frequent. They're sort of "The guys" as they are too big to move around easily and too old for people to buy, so I've seen them every visit since I started going in 2009. I think one is an IBM and the other says Star. 9:00 Did you ever take the picture? 19:52 I think "PRNTST-1" is PRiNter TeST-1 not PRiNT STat 34:28 I think that Oki ribbon might fit my Microline 182 Turbo / 186, interestingly enough

That is pretty aawesome.Is there any way to retro fit lower case letters into the printer? The quality is pretty darn good, certainly on par with the Citizen 120D+ 9 pin I bought for my Amiga c. 1991. Though of course that was an regular size printer.

Thanks, I've got a PR40 but in a larger metal case from SWTPC. Never tried to get it working, having watched your great video it seems this will not be a quick job! Do you have SWTPC BASIC for your 6800, might this have PR40 printer support?

this is probably what you get if you ask a car factory to make you a computer printer.