Raising the Digital Dead Ep. 1 - The Sol Prototype

[@TechTimeTraveller]

This was originally one video but I split it because I wanted to launch the series on 🎃. So I split the video in two, and will finish the second part shortly. This is sort of a backgrounder. The second part, where I discuss the process, anticipated challenges and then build a model out of box, will be out very soon. Hope this sort of thing will be of interest!

[@tezinho81]

Very interesting indeed, you gain +1 subscriber!

[@markmaker2488]

+ 2 subscribed

[@mao2233]

@@markmaker2488 Previously subscribed, but I want to encourage you (TTT) to move forward with this series. It looks very interesting. I also very much like the way you limn out your projects. Your background videos are really interesting and set the table for the project. Impressive work, sir.

[@tezinho81]

@@CoruscationsOfIneptitude there is definitely method in his madness!!!

[@Nightowl_IT]

Just ask them to make HQ photos of the original board from both sides.

[@ragrabau]

Awesome! I too started to built the TV Typewriter, but ran into issues back in 1973. I couldn't get the board as I did not have a way to make that big and complex of a board, and two layers - no way. The SOL terminal article was a bit thin on details, so I didn't even try. Several months later, with my scrimp and savings I was able to buy my brand new IMSAI 8080. Not the first one, but a low serial number. Fun kit to build. And all of this while I was still in the Navy. I look forward to more from your channel and can't wait for part 2.

[@QuintusCunctator]

"Lee Felsenstein told me it's probably not going to work". Wow, talk about a challenge! We're in for a treat! Congrats, I'll be waiting for the next video with glee

[@guitardunce7571]

Even if you weren't doing these videos, I'd say go for it. Your interest, passion and dedication to this is visible from space. I have too many other hobbies to jump in with a soldering iron and an old magazine, but your enthusiasm builds mine for my own, and preservation is a good thing in an industry that throws everything out once its not completely viable, and thats a shame.

[@AjinkyaMahajan]

I will try to replicate it as a soft core on an FPGA. Thanks for another great episode Cheers !!

[@TechTimeTraveller]

Let me know how you make out with that! That sounds really interesting!

[@OscarSommerbo]

Good luck! Sounds super fun.

[@ASquishyBean0126]

Your videos are so darn corny. I love it. It reminds me a lot of Technology Connections and the way you pull things out. its great and I love learning things that aren't covered so much and I feel like you do it awesomely!

[@Just.A.T-Rex]

Check out cathode Ray dude as well.

[@50shadesofbeige88]

Any day I learn about a new computer is a good day.

[@vonzigle]

I have a Sol Terminal Computer in my bedroom closet that was still working last time I tried it - runs with a North Star OS and has S-100 bus. Built it in 1977 from a kit.

[@natethefighter]

I've been working on doing some builds from David L Heiserman's book How to Design and Build Your Own TV Games from 1978. It's a real challenge - nearly every schematic has at least one mistake in it, and a lot of detective work is needed to chase down the solution. Good luck to you with this build, even with mistakes in the build guide, you can do it!

[@TechTimeTraveller]

Yeah schematic mistakes unfortunately are quite common. A few people fried their TV Typewriters back in the day because they followed the schematic instead of what was laid out on the PCB sometimes when there was doubt.

[@hicknopunk]

@@TechTimeTraveller oh man

[@williamharris8367]

I really like these long, deep-dive videos into the history of obscure and forgotten technology companies. I realize that they take a lot of effort to produce, but they are well worth it!

[@CZPC]

Very hyped for this one.

[@osgrov]

This is completely awesome, mad props to you. I'll be watching this closely. :) I remember reading back issues of Popular Electronics as a kiddo in the early 80s, and actually do remember the SOL. Never seen one running though, much less built one. I'm useless with hardware, been a software guy all my life, hehe. The best of luck getting this off the ground, I'll eagerly await the next episode.

[@1944GPW]

The australian Applied Technology S-100 machine had a video card based on the PT VDM-1. I seem to remember some of the games I played on mine (like Target) had 'Copyright Processor Technology' on the splash screen. Anyway this machine had a very useful BIOS called DGOS that fitted into a single 2K 2716. This had examine, change, go, cassette load/save (Kansas City), realtime clock as well as keyboard read and 64x16 screen terminal hooks. The fully annotated assembler source for this is on the net and I reckon it could be a good fit for the SIT. The AT S-100 system was later redesigned as an all-in-one machine known as the Microbee.

[@Godzilla_Jesus]

F'n subscribed, this is a great idea for a series.

[@RudysRetroIntel]

Fanatic!! Looking forward towards your next video! Going back to these great magazines and rebuilding is awesome! Thanks for sharing!

[@OscarSommerbo]

Have you contacted the museum? They will never allow you to take the prototype apart, as you say, but they might be up for a curator/archivist to take it apart and carefully record the dimensions as it is a part of the history of the device. Further, they would probably while disassembling the prototype take lots of pictures, those would help with the jumper wire issue. I don't know what kind of museum it is, but if they are a serious museum, they would be thrilled with someone building a working replica, as the physical object is only half the story (or even less) and would therefore be interested in helping, as long as it doesn't endanger the real prototype. For example, they probably wouldn't pry out the ROMs to image them, but rather jury-rig something to image them in place. My main point is, ask them for physical dimensions of every part, at worse they turn you down. Edit: The Computer History Museum seems to be a "real" museum, with staff, and curators etc. I assume they could provide you with exact dimensions and photographs. The issue is probably cost and time. But again ask them.

[@garywilkinson5887]

I really enjoyed the in-depth documentary on this episode and I’m looking forward to watching the build progress over the remaining episodes.

[@MichaelEhling]

This series is a fun, creative idea. Can't wait to see it unfold.

[@OscarSommerbo]

Lee sounds like a superinteresting guy, clearly into the counter culture at UC Berkley of the late 60s, early 70s, and with some strange and wonderful philosophical ideas about digital design.

[@chasonlapointe]

I can't wait to see part two, I love how knowledgeable and entertaining you are, I bet you'd be an amazing tour guide through a computer history museum!

[@JohnKiniston]

This was such a great video, I really enjoy how you present and look forward to the next installment.

[@TechTimeTraveller]

Thank you!

[@Danglebarry62]

This is brilliant. I'm looking forward to seeing this come together!

[@joshuamacdonald4913]

This is spooky. (Haha) I just had a similar conversation today when I was discussing the fact that I am building a cosmac elf with a classmate. (I'm not that young, I recently went back to school). Its not about the functionality of the machine as much as that it needs to function as the original did. Yes it's under powered and yes I could emulate it but thats not the point. Unfortunately tho there are some "modern equivalent " components that are "acceptable " but will be replaced as I find more suitable parts. I really like the idea of this series of videos and if I wasn't on the other side of the country I would be lending a hand a much as possible. Great video as always, keel em coming.

[@TechTimeTraveller]

I was going to build an ELF but ended up aquiring a couple of originals, so that put paid to that. But I still might one day.. the build experience is just as valuable as the machine. Best of luck with yours!

[@GeeWillikersMan]

19:00 -ish Right on. It's not the destination, its the journey.

[@jeremiefaucher-goulet3365]

This should be a very interesting series. I look forward to it.

[@lanz1987]

Love the premise of this series and really looking forward to it.

[@JohnyPaprikas]

Love the idea. Good luck!

[@wimwiddershins]

Like many of these types of fun projects, it's the journey not the destination.

[@tighematt]

Great idea, looking forward to the rest of the series. Good luck!

[@Space_Reptile]

I love this project already, but I have a suggestion: try and put the s100 Port in the original Position so it wont need the jumpers, yes this might not be a perfekt replica, but in spirit it's the same mashine as it was ment to have the Port in the other Position if not for the last Minute change

[@BigCar2]

Looking forward to seeing it working (or not)!

[@Oddzball3]

Seriously underrated channel, good stuff

[@chrismcovell]

I love your videos, the level of information in each of them, and your choice of topics. Really looking forward to seeing this hardware project come together, whether working or not.

[@Arivia1]

Always a pleasure!

[@tschak909]

This is a good direction. :)

[@joshhiner729]

Great video. Love the idea and plan. Watching through them now.

[@jaut-76]

Can’t wait to see what the outcome becomes. I love the sol 20 and wish I could own one but saying my luck with the 70s microcomputers that won’t happen soon.

[@alk7934]

Good luck!

[@50shadesofbeige88]

Nice 2 camera shoot. Your production quality has come a long way. Keep it up!

[@tuppyglossop222]

Yes, but is somewhat disconcerting when you are talking to the side of the camera.

[@InfiniteLoop]

Wow, this is awesome! I cannot wait to see more. I love this obsolete stuff because it like all the early computers, has charm something sorely lost when ibm took Over.

[@thebyteattic]

This is a fantastic project, great initiative. And the alternate history bit is most delightful. I very much look forward to it! If there's any way I could help, let me know.

[@GeografiaDasCoisas]

Why? Because you're a real hero. The history is going to the nothing... Congrats!!!

[@mountainkingelectronics]

This episode is a great example of what makes your channel and your content above the rest! Your genuine love and respect of the technology and it's history is unquestionable and refreshing. So many other similar channels seem to make fun of the technology that they are supposedly admiring. Building these early projects really does have a time travelling effect and I'm so excited that you are going to be making episodes that focus on that. If you need some technical advice please feel free to contact me, there's a lot that I don't know and but I have had a lot of experience building electronic devices so I may be able to help. Alan

[@GeneralKenobiSIYE]

If I had the money, I'd try to cram as much power into a late 70s computer as possible.

[@laserhawk64]

Sounds exciting! I look forward to further episodes :)

[@PaleozoicPCs]

Alas I know that building an exact replica of a museum piece like that from scratch is a thing I'm never going to be able to bring myself to do. I mean, I'm not saying I'd settle for just building the case and stuffing a Raspberry Pi in it, that's not my bag, but, man, I look at those schematics full of unobtanium/expensive parts and the itch to replace those ancient EPROMs and SRAMs with more modern ones you can snag for $2 would just be too strong to resist. Might also be tough to avoid redesigning it to use a Z80 instead of an 8080, voltage and clock requirements are a lot friendlier... Of course, taking a look at machines like the SOL and figuring out how to strategically cheap it out is pretty much exactly what Radio Shack did within a few months of its introduction, resulting in the TRS-80. History doesn't always repeat itself but it certainly tends to rhyme. ;) Editorializing, it kind of seems like the design of the "magazine version" of the SOL was kind of a train wreck of conflicting priorities that weren't resolved before the homework was due. If they really had set out to just build a smart terminal all the effort making the expansion connector S-100 compatible (and in the end not quite entirely managing it anyway) seems like a rathole they could have avoided. The Altair's original design of having dual unidirectional data buses is inherently suboptimal; the 8080's data pins are natively bidirectional, the Altair implemented the dual buses mainly to simplify the implementation of the front panel, which most new computers didn't even have any more after 1976. They could have saved a lot of hassle by just stubbing out a piggyback board connector that mostly just replicated the CPU's pinout and used external circuitry to convert it into something closer to S100 if they really specifically wanted it in an expansion box; third-party S100 chassis were built for machines like the TRS-80 that did exactly that. I dunno, I guess it really does feel like what ended up in the magazine was essentially a random snapshot of time taken right around the moment they'd reconsidered whether they were building a terminal or a computer; they were convinced that a "computer" needed to be S100 out of the box and the layout that ended up in the magazine was the first crack at trying to wedge one in there heck or high water. It sounds like they knew it was unworkable even when the magazine was coming off the printing presses but, well, that's deadlines for you.

[@TwoWholeWorms]

Looking forward to part 2! Will be really interesting to see if you _can_ get it going!

[@rgmolpus]

Fantastic! With modern Autorouters, it may be possible to make a 'REV 2' board, without the 100 jumpers - closer to a commercial product. If you can find a proper cassette deck, that would be even nicer.

[@justinhelget853]

in my mid 40s and grew up with the apple 2 and dos machines, i love love love s100 machines. i have a soft spot for the cromemco machines especially the late 80s x68000 machines

[@colonelbarker]

I'm excited for this project. I may have to dig out the magazines and have a look over the schematics in detail, I guess. Are you posting about this on social media anywhere where we can get involved with following along in more detail?

[@mckelepic]

amazing video, your channel is great. such well made genuine content

[@snooks5607]

24:05 since it's going to be alternate history version anyway would it make sense to recreate the schematic in EDA and shuffle things around a little to minimise the jumper wires?

[@Symplegades]

The more of your videos I watch, the more i realize that when I next upgrade my machine, I'm gonna have to go Mini-ITX (or some similar SFF) and build a homebrew 8-bit wedge case to put it in.

[@TechTimeTraveller]

There's something about wedge form factor cases, especially with wood components..

[@bobweiram6321]

I love how the word "star" appeared in so many brands during the 70s-80s.

[@ethanspaziani1070]

You have the same imagination and adventurous Spirit as me I would love to see an alternate history version of this machine with a functioning tape deck and full-on computative power taking something in theory and making it into a full reality 100% unique don't let it bother you too much that it's not going to be exactly like the original because it's not meant to be it's going to be yours! 100% unique the only one like it in the world

[@TheGunnarRoxen]

Madness! I love it. I totally get the appeal, but that sounds like a lot to bite off.

[@hicknopunk]

I love how that keyboard looks. I'd love to MUD on that bad boy.

[@TrashfordKent]

Building something that might not work or is flawed, I think this trait has persisted somewhat ;) looking forward to the journey 👍

[@jtveg]

Thanks for sharing. 😉👌🏻

[@frankowalker4662]

Wow. I'm looking forward to this build, it's going to be fun. (for us). Using a Pi emulator would'nt give the same feeling or experience as using the real hardware. Plus you get the satisfaction of having a homebuilt computer that you have personally toiled over and sworn at. :)

[@laustinspeiss]

3:49 massively underselling AMPEX !

[@williamharris8367]

Have you tried contacting the Computer History Museum? I do agree that they are not going to let you disassemble an historic artifact, but they _may_ already have documentation on file with detailed measurements, etc. In art galleries, normally only the front of a painting is on display. That said, the gallery will still have a record of any inscriptions or other important information that may be on the back. Presumably this information is made available to those who need it for research purposes.

[@KaldekBoch]

I missed TTT over the last few weeks!

[@justovision]

When it comes to hobbies and passion projects"why" is the only stupid question. Good luck!

[@cAHOONah]

I heard/read somewhere, that the walnut side panels were used, cause Marsh had some left from the clock project and a befriended carpenter could provide them for little money.

[@TechTimeTraveller]

The account Lee gave in ROM suggested the clock project didn't happen at all, but possibly they acquired the wood in anticipation of doing that.

[@Spookieham]

Those who say build the TV typewriter out of a pi completely and utterly miss the entire point.

[@penfold7800]

The programming of the Second EPROM must be written down somewhere, or a schematic at least. Im guessing that its possible that the way it worked and what the machine was capable of could have possibly posed a risk to classified sensitive computer systems of the day (imagine a portable intelegent terminal that could do the same thing as a fixed four-cabinet machine AND be interfaced with it without interuption) ...so it inevitably got mothballed.

[@rutabagasteu]

I remember seeing the adverts for the Sol 20, but didn't have the dollars to get it.

[@stevetodd7383]

If you have the schematics but an unreliable idea of the board layout then you could always feed the schematic into an EDA package like KiCad, feed it the board dimensions and connector positions and have it work out all the routing and traces for you. There’s a fair chance that, with a two layer board, it will manage to handle the whole design without bodge wires. Not period exact but in keeping with the spirit.

[@tcaldwe]

Usagi electric mentioned you in a video!

[@bzuidgeest]

Why? Because i can. Enough explanation 🤣

[@Jkauppa]

capacitive touch-screen flex keyboard, very simple, supports image on the background if transparent

[@Jkauppa]

why dont you re-engineer it to work with the firmware, from scratch

[@Jkauppa]

its only about the processor interfacing all the other stuff

[@Jkauppa]

adapting the original schematic to an operational prototype

[@elwro07]

Are you going to design and fabricate PCBs for it?

[@TechTimeTraveller]

I'm going to fabricate PCBs using the original plans.

[@AiOinc1]

Fantastic video as always, all it was missing was a cheesy black and white scene where you mix components together like you're reviving Dracula! I've never understood the "Just put an RPi in it" people. If I wanted a crappy slow computer for cheap, I'd have just 3D printed a chintzy case for it and been done with. Why would anyone bother to go through the effort of fully recreating something like this just to put literally the cheapest modern crap available inside it? That would entirely defeat the purpose of the project.

[@matthewrease2376]

Woodgrain 😍

[@thrillscience]

I think that's a 14.3181 MHz crystal. at 12:53 (You said 13.3784) It's a very common frequency because it's 4x the colorburst frequency. Also, I don't think it's fair to call it a "replica." If you're building it from plans that appeared in a magazine, the resulting item is the actual device. There's no time limit on when the article appears and when it's built, is there?

[@TechTimeTraveller]

Yes that's just a shot of the VDM-1 board again.. I didn't have a 13.3784 crystal and the photos of the board on the original are too blurry. I'll have to confirm what actual speed was used, my source on that was Lee's interview in ROM Magazine, I think it was July 1977. Regarding replica vs. real - that's a very good question. I consider my TV Typewriter to be real, not replica, vintage parts but not vintage built. I qualify it as real because the article offered the plans for someone to build my own. I consider it a replica only from the standpoint that I made it resemble Don's prototype, which is unique. Something like an Apple-1 replica on the other hand, I would consider a replica all the way around since the only way someone could have one was to purchase it from the two Steves. With this Sol prototype, I think it's more like my TVT - it will be a real SIT, I'm hoping to get almost all of it done with vintage components, but it will resemble the museum unit so it'd be considered a replica of that. Might be an interesting topic for a future video. The people who really care about the distinction are collectors - for a lot of them it's a replica if it's not built in the original time period. Many thanks for your comment and for watching!

[@dr.elvis.h.christ]

So far ahead of their time they had a Prius.

[@coyote_den]

Sadly, Tom Swift's legacy is best known due to a far worse device these days: Tom A Swift's Electric Rifle. TASER.

[@TechTimeTraveller]

I didn't know this!

[@Sevenigma777]

How many times did you have to say "Felsenstein"? Lol

[@zeos386sx]

you used to could buy sol20's for $30 on ebay.

[@Malephex]

19:27 ... have you looked at the demographics of your channel? You are preaching to the choir! No w get on with the building :)

[@KarlHamilton]

sented

[@bitrage.]

You MUST BE a masochist....🤣

[@coffeefox5703]

I hope you can make it work. If the engineers could do it at the last minute, I'm sure you can do it too. :D