Rare 70's Computer Find - Will It Work??? SWTPC 6809 

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Look mum old computer

Can we just shout out how dope the SWTPC logo is?

Legendary!

"IPL" refers to Initial Program Load. With a computer of this era you needed to boot a program from the disk that allowed the computer to access the disk (like the boot sector on the PC). Is the disk you're using a boot disk? Usually users would only place the OS onto specific disks, boot from them then change to the application disk to actually work. In my first job in 1985 after graduating I worked for a software house and one of the customers had a SWTPC 6809 computer that looked uncannily like the one you have there. The prices in the list are accurate, commercial microcomputers were so expensive! That's why consumer computers like the PET, Apple and TRS-80 were such a revolution, coming out at a tenth of the price of other systems. And single board kits ike the NASCOM-1, UK101, ZX80/81 were another revolution bringing prices down to levels affordable to the general public. As far as I recall SWTPC made "commercial" offerings as indicated in the catalogue and kits based on the boards, so if you wanted you could construct one yourself. The "bodge" wires on the PCBs were typical of the time, even from major manufacturers due to the high cost of mastering the artwork for the PCBs (no computer CAD for any but the higest end manufacturers like IBM and DEC!) so they would do extensive rework on PCBs to save costs. Also these were manufactured in the hundreds rather than the thousands. It's a nice machine and a very rare find! One tip: computer enthusiasts of this era used to connect an amplifier to one of the higher address lines and write programs to precisely time access to (unpopulated) memory addresses to make square wave tunes - maybe thats something you can try out your 6809 programming skills on! Luckily the 6809 had a fairly advanced architecture so programming it is fairly straightforward compared to other microprocessors of the time.

IPL means I-nitial P-rogram L-oad. This means that the system is trying to load the *operating system.* It's probably on a diskette labeled *Flex* or something similar.

Looks like there is going to be a new channel, "Look Mum No Synths"

IPL probably means Initial Program Load. So you may just need to insert a OS disk and it will try to boot from it.

This is beautiful! Look at that microcomputer!

"I just thought with my heart, and that is usually the worst thing to ever do." Don’t call me out like that, damn.

Clean the drive heads and clean the floppy disk before use. On the drive heads gently use q-tips with 96 proof alcohol. To clean the floppy disks use a mixture of 30% isopropyl alcohol mixed with distilled water. Use a microfiber cloth to gentle clean it. Don’t use q-tips on the floppy disks. Great find and I’ll tune in tomorrow.

I like the nice sharp green text on that old terminal. I have a coin-op Joust video game from 1982 that uses a 6809 CPU. Love to see ancient stuff like that still working.

That is beautiful! And working! It's a seriously high end machine, and if you have more terminals, you should be able to plug them all in and have multiple people using it at once... That machine's going to boot from floppy, so it'll want a specific OS disk in the drive before it'll do anything. Chances are that accounting disk isn't bootable. I saw a reference to FLEX, which is a classic (and hard to use) OS for 6809 machines, so you might want to search for a disk labelled something like 'FLEX boot disk' or 'FLEX work disk'. This _won't_ be the original --- the user will make a copy of the original and works with that (so they can write files to it). The disk drive will probably need a clean. Dust will build up in the congealed lubricant on the rails and bearings, which will need cleaning and relubricating. The disk heads will also need cleaning by wiping them gently with a cotton bud with a little IPA on it (the alcohol, not the, er, other kind of alcohol). Check the disks for mould or damage. If you get any of that on the heads you'll need to clean the heads again. Chances are that it contains no speaker; the beep was made by the terminal and probably isn't tunable. You might be able to make noises by bitbanging an output port from 6809 machine code, and hooking that up to a speaker. You ought to be able to hand-assemble this and enter it directly from the ROM monitor (it should only be a handful of bytes), so if the disk drive doesn't work then all is not lost. **Edit:** I think you can use a floppy emulator on one of these, although you'll need to wire up an adapter. That might be easier than trying to write to 8" floppies if you want to copy files to it (I've actually got some hardware that might let you do that: cowlark.com/fluxengine/).

I had a SWTPC 6800 system, the original 1975 version. The complete kit, consisting of the black and silver box like yours, an older all white terminal, and a cassette interface (no floppy drives) cost around $1000 USD in 1975. The motherboard has several 50 pin connectors (known as the SS50 bus) for things like the processor board (I upgraded to the MC6809 board) memory boards, the floppy drives, and a DIY video controller for putting txt and crude graphics onto a TV screen. There is a row of I/O connectors along the back of the motherboard, where smaller I/O boards plug in. There is a serial interface that operates the terminal, and parallel interface boards that send 8 bits of parallel data for things like printers. You can make a simple resistor ladder that can turn the parallel output into an 8 bit D/A converter for making sound or chiptune quality music. The parallel port card can be used for triggering drum synths, or other "button push" type operations. I had three or four of them in my system. I eventually gave it all to a museum sometime in the late 1980's. SWTPC did unsuccessfully try to get into the business computer market, that's the stuff in that pricey catalog. The machine you have is the home / hobbyist version. SWTPC also made a lot of audio amplifier kits under the Tiger name.

That computer has an aesthetic that would fit right in on the set of 2001.

That is ace great video I not long started secondary school back in 83 Its a great piece of computer history

I would love to play around with such a old Computer. This thing is insane :3

In high school my friend used to do intern stuff there. I would go and follow him and talk to the engineers and hang out. Those were the days. I learned vi while playing around there. Our high school had 2 of these systems running their version of UNIX with 10 of those terminals attached to it. We used it for a C programming class in 1983.

You haven't lived until you've set index timing and adjusted radial head alignment with an Oscilloscope on those 8" floppies..!

Fantastic! When I was in my early 20 in the mid of 80s I was programming a 6809 in assembler and using a unix like os called OS9.

I have that same crimping tool for 15 years, without knowing what it was for... thanks for the revelation!

Old Printer here. That was the machine is what ran our compugraphic typesetter in the Prepress Shop. Every function is a weird proprietary command, probably somewhere in the big binder. Ours was further complicated by additional function buttons to produce data for print medium. Those were added to the layout for professional publishing by being waxed. Photoshop it was not. Good luck.

Fun Fact: The US nuclear arsenal was controlled with 8" floppy disk up until 2019. Much rather see these machines used for art than bombs.

shit was built to last back in the 80' and prior. sweet looking machine. I hope to see it in the museum, when I'll be finally able to visit.

Nostalgia rush! I used one of these as a student back in '83 to '85. I don't know if we used that particular terminal or not, but it was definitely a SWTP computer.

The terminal is my favorite part. I love the look of old terminals.

LOVE old computers and terminals like that. Commands for all those generation of systems were very proprietary, so since you have the manuals, just read them through and they'll cover most of the general operation of it. They were not exactly intuitive, but once you learn how each company's system worked, it'll start to make sense. :)

Brilliant.when I was a lad the first computer I used at school was a print only computer and it printed on a big golf ball type printer no monitor . It was a pleasure to see it print "ready" .I am 56 but it was old then. But respect to you.

Absolutely awesome! Score! The doubled characters would have been to do with local echo on the terminal. IPL is Initial Program Loader. You need a system disk, and the other disk seemed to be labelled as that. There may have actually been some kind of sound card made. Oh yes, the terminal being RS232 serial could also be used with a Linux system.

I would 100% be there for more computer content. I just started getting into software development pretty heavy in the last year, and computer history has proven to be both incredibly entertaining and useful in the course of designing tech solutions. I dig the way you approach it because the dry approach (employed by schools and corporations) alienates young people from the innovation process, encouraging them to learn only what is necessary to gain what they perceive, due to their conditioning, to be a competitive edge.

Maybe CuriousMarc would be interested in helping you out. He does allot of this stuff.

Much love from France & thank you for your amazing work !

I love the 70s futuristic aesthetic. Somewhere between 2001: A Space Odyssey and Alien.

It's like crossing Marilyn on the streets again, isn't it? Ol' fashioned beauty! Many things to say... 1) your contents are awesome! Making music out of a trashcan, 2) don't be concerned about it this fits your channel... People love your contents because of the power you inject in every project! 3) the IPL is the bootloader, is the same message that DOS gave when working on a diskette-based pc and the one in the drive didn't have the io.sys/command.com in it. 4) I'm an old 6800/6500 programmer, so I know the families, and the USART in the 68 family is the 6850 ACIA, (so, may the computer have an aux serial Port with one) which, I remember, can be set to synchronous mode and, therefore, drive MIDI! You're not too far! Stay creative, stay cool! (Dr Mix) Cheers from Argentina! 👏

Sam, wire an incandescent lamp between the device and supply in future... If anything is blown, the lamp will take the whack rather than the components within the device. A lot of electronics channels use this method on old equipment when powering up a device that hasn't had any juice in a while...

Well, that went a lot smoother than I expected. Others have already answered your IPL question, but I would add that often, dual drive systems from this era had a preference as to which drive contained the OS disk. If I remember correctly the Fairlight CMI is one example.

If it's got some sort of external I/O port (serial/parallel/user) you can turn it into all sorts of things, from a drum machine (you could set it to trigger the twin-t oscillator board you built from that 70s magazine) to a CMI Fairlight clone.

I'm 63 and worked with similar hardware way back when.So all I can say is WOW!

So heres some info about the operating system for this CPU en.m.wikipedia.org/wiki/OS-9

Awesome to see you talking about computers of this vintage on your channel. Computers of this era and modular synthesizers share a lot in common, lot of discrete logic and stuff to tinker around with

What a LOVELY S-100 computer!

I like the passive-aggressive "WHAT??" reply when it doesn't understand. Instead of the usual "Bad command or filename"

IPL stands for Initial Program Load. IE. bootstrap the computer to load the OS from the floppy disc. Make sure you have a boot disk in the drive, or it will not be able to bootstrap itself...

Congratulations. This is completely nuts. I hope the old techs come out of the mist and get this device singing.

Thanks for taking the time to make the videos you do and share them with us... Absolutly fantastic

Omg. That was my first computer and first love. I still remember the first time I sat at this thing. It started my love with computing and my career. Brilliant find mate!!!

This is amazing. Love old computers. Hope to see this thing continue to come alive!

The fact you have Thomann PA speakers installed in your museum pleases me, they are very good

Lovely bit of kit! I particularly like the logo, and the swoopy terminal shape. If anyone can put that back to use you certainly can.

Oh man, that feeling when stuff "just works." So awesome. Looking forward to hearing some tunes on this.

Just what’s needed. Thanks.

I saved for the better part of a year with my 3 paper routes to get a TRS-80 back then. It ran the 6809E. Cost $100 to upgrade it from 16k to 64k. I still have several of them in my storage.

Very interesting find there, S-BUG looks like a ROM monitor, quite common practice for the time to have some basic functions in ROM. Looks like you dropped lucky everything seems to be mostly working. Give the floppy drives a good clean and also inspect the surface of the floppies; oxide build up, dust and mould are quite common.

Thanks for putting up this great video! Also, thanks for plugging my own video and letting more people know about this amazing microcomputer. The error you received is simply letting you know that the 6809 is looking for an OS to load (e.g. FLEX). Hopefully, you have a copy in your collection of disks that came with it. If the disks are intermittent about loading data, then be sure to gently clean the read/write heads on those floppy drives so that the data remains good on the disks. These systems were made to last, but they do need some basic cleaning every now and then. With regard to music, they absolutely can be made to produce melodies (probably one note at a time), but it's worth looking up what music cards were made for it because maybe there's some 4-channel card out there just waiting for a composer to program something on it. While 6809 Assembly and C are mostly what I programmed mine with, I also used a fantastic language called PL/9 that is similar to C and compiles some very efficient 6809 code. There is a small, but mighty group of enthusiasts like myself who still tinker with these things. They are far more knowledgeable about the technical stuff and hardware side. I'm just an amateur retroprogramming guy. By the way, is that SWTPC Logo the coolest thing ever or what? I have a huge poster on my wall of that and even incorporated it into the title screen of my Cribbage game. It's so retrofuturistic, almost like something you'd see on an alien spacecraft. I look forward to more videos on this!

Yeah, those prices look about right for the era

MAD props for having a ribbon-cable crimping thing!

it is amazing that it even turned on!!!! what a find you have there Sam !!!

The audience for this channel really is a cut about the normal. Most channels where they veer off to something new they get a load of hate with people complaining they didn't sub for this! But LMNC veers all over to some of the strangest topics and the comments show people just love it. I know channel creators get a lot of praise but today I'm going to praise the subscribers. Not a plonker among them.

Wow, what a beast! My first home computer was a Tandy TRS-80 Color Computer 2, which also used a 6809.

Dude, that thing is badass!! Congrats. Sounds like a freight train when you're typing 😂 Love this old hardware, thanks for posting.

"Would you like to play thermonuclear war"

Amazing find! If you thought synths were a rabbit hole... welcome to vintage computers! ;-)

Absolutely a gas to watch!!! So entertaining and thanks for your preposterous stuff!!!

Awesome find - I love the look of those old machines

LOOK MUM ONE COMPUTER ;) , That’s such a great James Bond era looking terminal! Just seeing it was beautiful, but seeing it come to life was AMAZING!!

very cool find and video. I'm looking forward to seeing more about this mystery machine.

"I'm Look Mum No Computer. This is a computer." Well, I certainly can't argue with that ;D.

The 6809 was not only the basis for the SWTP machine as well as the Radio Shack Color Computer, but was also the "brains" of the Voyager spacecraft. One of the perks of those late '70s and early '80s machines is that they often make the various busses easily accessible. I suspect this was largely because they rarely came with "enough" stuff like RAM or other storage capabilities, and needed to provide some means to expand. If your travels ever put you in touch with someone willing to part with one, SWTP also made something they called the Ambience Synthesizer (2AS-A model). It contains SIX, count 'em, SIX Reticon SAD1024 bucket brigade chips.. Yowza!!!

Brings back memories, My first job was working for this company.

Awesome video man, how the hell is it that quite! Love old PC's crazy to think that is only 43 years old to where we are now, always amazes me!

If I tried to buy something like that, it'd take me three days to figure out why it wasn't booting, then another three weeks to get parts. Nice job!

Don't have time to watch YET.. But you Are 1 Crazy Dude. I Love It. Peace from Pennsylvania mountains..

Dude… I learned to program in Algol on an Elliott 803 at Cannock Chase Technical College. That was so retro that the 1K memory was made up of ferrite rings. The teletypewriter used to make the punched tapes the computer used actually ran on compressed air and when you turned off the power to them the whole lot of keys would drop into the chassis. That was the machine that got me so into computers (I got nothing but A’s in that class) that the teacher gave me my own key to the computer room so I could use it whenever I wanted… which was amazing because at Grammar School I managed to get the record for the most number of E’s on a report card… I missed out on a full card of E’s by getting all A’s for Woodwork and metalwork. I think I had ADHD and only being able to work stuff with my hands stopped my brain from running all over the place.

Very nice indeed. That terminal is quite the absolute unit. And they came from here in the Alamo City! Unfortunately when I moved here as a high schooler in 1979, I never quite caught on to them being over there by the airport, until they were already gone. However I was at the 10BitWorks hackerspace one day a few years ago when someone brought in what was left of their repair parts collection (basically a big box with mostly tubes of chips), but I don't know if they'd still have them. As for getting it to make music, I suppose one way would be to make a board (it uses the "SS-50" bus, sort of like S-100 only different) with two 8-bit ports (maybe a single PIA or VIA chip) and either an R2R ladder or an A-to-D chip. Or you could hook up one of the standard sound chips of the day (even a SID!) and then it wouldn't be too much different from a C64 or an Atari. And all that RAM? A decade or so later and you could get 32K on a single SRAM chip. So much easier to make a breadboard computer with! 4K DRAMs are really taking a step back in time! Oh and 7:18 notice the "Motorola Memory Systems" on the board, so those boards may have been made by Motorola, not SWTPC.

I guess I'm going to have to get mine out of the garage and get it running again.

HI, so a general thing to check on anything this old are leaking Batteries, X2 filter caps in the power supply and tantalum capacitors, both of these are know to let out the magic smoke. Then the obvious bulging caps that can be out of spec. Looks like you have been very lucky and it looks beautiful !

Cool computer! My first computer was the commodore VIC 20 with a tape drive, we had loads of fun programming it and playing games on it in the late 80s

The desk image on the cover of the quote docs, so "retro-futuristic" love it.

This is going to be exciting! Motorola 6809 and two 8” floppy drives, you’ve acquired some parts that where also in the Fairlight. On these old computers the floppy drives often use the Shurgard interface. The drives are often labelled device 0 and 1. The standard allowed for 4 drives on a ribbon cable, unlike the IBM pc which changed up a few things. Most floppy cables are 34 pins, but I think these 8” drives may use 50 pin ribbon cables. Important to know is the difference between the original shurgard standard and the IBM standard is the device jumper function. I have a feeling that you’ve got the access the drives by adressing them with number 0 or 1. At least On the Acorn machines it works this way. Also the disk motor starts spinning right away, this kind of suggests that it uses the original shurgard standard. It’s an interesting looking system, that’s for sure!

Keep going and never stop. True technolust is beautiful to experience...

I collect & restor vintage computers, you have found something special. Main thing to look out for is RIFA caps, RAM oftern fails & as you say the voltages on the PSU's. With the floppy drives I recomend lubing up all the moving parts. Also clean the heads in the drive.

You have honestly made me less afraid to try things. I can't thank you enough.

I have a master copy of the 'Flex-09' operating system on 5.25 inch disc, if you need it. You could drive the AY-8910 music chips from it which were from the same era. I have an unrestored 6800 system by the same people, with one of their kit built terminals. Doesn't have discs but has a wonderful dual casette interface, instead.

When you did the terminal cable... I was all "no mate, it's more complicated than that.... it's not going to work" AND IT DID... so I'll shut my gob!

Thats gorgeous mate well done

Love it! I wouldn't have been able to walk away from it either! I don't see any audio stuff in there but i'm sure you could plonk in a card with an SN76489 or two on. keep it true to it's heritage though, it'd be kinda wrong with a SID or AY-3-8910 etc. shouldn't be to difficult hardware wise, maybe even adding an input or two to control it (MIDI?!). the hard part will be the software, Midi controller in 6809 assembly language anyone?

Love the logo name on that thing! The whole design is amazing.

What an absolute beauty of a find! And yes, would love to see more vintage computer vids. We need a British version of the 8 Bit Guy.

Looks like the read/write head on the floppy drive isn't moving, which is pretty typical. You could try getting in touch with The 8-Bit Guy. He is going through the hell in Texas right now though, so I'm not sure if he has time. But he's the first person that I can think of that might have knowledge of this.

Very, very cool machine you've picked up there. As others have mentioned, you need to boot an OS from floppy and the ones you put in it in the video probably weren't bootable disks, just data disks. There were 3 operating systems you were likely to find on an SWTPc 6809 -- 1. FLEX -- similar to CP/M, but for the 6800/6809 rather than 8080/Z80. 2. UNIFLEX -- from the makers of FLEX. This was a real rarity, and was supposed to be UNIX-like. 3. OS-9. This operating system, named after the 6809 microprocessor was a real-time, preemptive multitasking, multi-user OS that was also vaguely UNIX-inspired, but very modular. OS-9 would also later run on the Tandy (TRS-80) Color Computer line and the Dragon 64. In fact, the very same binaries that run on either of those systems will work on an SWTPc 6809 running OS-9, provided that they don't use any special hardware that isn't in the SWTPc. The Fairlight synth actually also runs OS-9. Because it was quite popular on the CoCo and Dragon, as well as other embedded / industrial computers, there's quite a bit of software out there for OS-9. There's a great structured BASIC called BASIC09, there's a Pascal compiler, a C compiler, and there are quite a few CoCo hobbyists using it today. In fact, a re-written version called NitrOS-9 is still under development by hobbyists -- mostly CoCo enthusiasts. Even if your system didn't come with OS-9 boot disks, the disk image files are obtainable on the Interwebs, and it should be possible to write them to a disk. If you can't get that to work with the 8" floppy drives, one of those Gotek drives set up as a 720K drive should work. There's a lot of expertise on the CoCo OS-9/NitrOS-9 Facebook group ( facebook.com/groups/1929079184021683 ). A boot disk for the SWTPc version of OS-9 can be found here: www.evenson-consulting.com/swtpc/ FLEX and UNIFLEX are pretty obscure now. But if you can get this thing to boot up OS-9 (you'll probably need 64K of RAM) you'll have lots of options for programming it. There's even a guy on your side of the pond making new hardware for those computers: www.corshamtech.com/product-category/ss-50-products/ I very much want to see what you can get this thing to do!

WOW !!! That is a beautiful setup !!!

My first exposure to computers was this beast - my dad imported "Sweetpack" into Australia (until the aussie dollar was floated in 1983 and it became unsustainable) to this day I remember that "load A register immediate" machine code is "86"

Kraftwerk "Computer World album cover has one of these

Love to see more videos on computers. You do have a knack for them.

Even if you can't make tunes with it (and quite frankly you probably can make the floppy drives sing at least) that would make a cracking exhibit at the museum. Maybe use it as a guestbook thing? Also I'm pretty sure you could drive the terminal from a Raspberry Pi if you wanted to, after all when it comes to Linux a tty is a tty, even a 100 year old electromechanical one as demonstrated by Curious Marc haha

That thing's about the same age as me. Cool to see a computer from before surface mount components.

Motorola 6809 is a nice processor! The send "twice" is actually send once and local echo on the terminal is set on. You need to set that off. Oooh I see now you figured it out :D This was a common error in my first full time job, where customers called and said that their "keyboard was stuck". The terminal had lost it's configuration and local echo is standard on. So we'd instruct them how to configure that. Later we actually made our system clever enough to once tell the system what terminal was connected to that port, and push a program string.

Love the look and the style of it, it could kinda be cool to have a modern pc in a shell like that

I knew this is gonna be epic ;) congratulations!

the shape, the logo. that ones a beauty