Sorry it took so long.. covid blew up 3 weeks in April. And brain fog is a real thing. But I did get it together and invested in a new Yeti X mic which I hope will put our audio problems to rest. Enjoy and thanks so much for watching!

"I hear EEPROM island is a nice place to visit, but just don't get too much sun" ...Sir, you are an electronics nerd of the highest magnitude, I tip my hat to you!

40 years ago some guy was having the same problems with his homebrew and gave up, unaware that someday someone would pick up his work without knowing it never worked. ;)

There's a TV series called Graveyard Cars where they restore classic cars found in horrible condition. Maybe you should call these episodes Graveyard Hardwares?

The first EEPROM, whose contents are shown at 22:20, looks like it's being used to decode specific control characters. They're using the EEPROM to replace a pile of decoding logic, by feeding the character code into the address pins and then having the eight data pins out of the EEPROM each indicate a specific character match. Notice how all the codes are 0x00 except for 8 characters (0x07, 0x09, 0x0B, 0x0C, 0x10, 0x16, 0x1A, 0x1C) each of which will set exactly one output line from the EEPROM high. This would have been used to generate control lines that trigger events such as backspace and newline to happen when those keys were pressed. I'm not sure what specific characters they're decoding, this looks like it might not be using the standard ASCII mapping. The second EEPROM, contents shown at 22:22, looks like it's performing some kind of character remapping. In a similar way to the previous EEPROM, the character code from the keyboard would be fed into the address lines, and the data out would then contain the remapped character code. It looks like most of the characters are passed through unchanged, as the data contents of the EEPROM are equal to the address for most of the address inputs, but characters in the range 00-0F and 7E-7F have been remapped. I'm not completely sure why they needed this, maybe the character generator chip doesn't have the same character mapping as the keyboard and they needed to change some things around. The third EEPROM, contents shown at 22:32, looks like it's also being used to generate specific control signals based on the character inputs. Most of the values in this EEPROM are 0x80, and I suspect that was being used to generate the signal to move the cursor one space to the right after a normal character was typed. It's also generating some other codes for some of the remapped and control characters, though again I'm not sure what as I don't know what the mapping is. Perhaps this one is being used to generate cursor movement in general? I'd have to see the schematic to say for sure.

Most of that is stuff straight from a 1970s Radio Shack. They had those Archer breadboards with edge connectors as well as IC sockets with wire wrap posts. It's amazing that back then anyone could walk into a Radio Shack then go home and build something like this.

That introduction was absolutely amazing... and so very true.... I have a terrible problem with "other people's garbage"

Back in the day I had that Radio Shack keyboard PCB. I was going to build a Cosmac Elf and try interfacing that keyboard to it. But the skills of teenager me weren't up to the challenge. It didn't help that in a few years I was able to buy an Atari 800 xl for less than the cost to finish it.

That thing is definitely computer It’s the computerist thing I’ve ever seen

"Radio shack with a bad case of Norovirus" Sweet Lord, my sides 😂 Welcome back. I work for public transit in a high exposure role. Have had the Vid a few times now. The brain fog is a real thing. Glad you made it. Endorsing more intro skits with tortured internal dialogues. Edit: Eeprom Island UV exposure jokes are high art. 🏝️

It really is a shame that it was an estate sale you got it from. It would be so interesting to pick the brain of who ever made this.

The commentary here was hilarious, this computer is probably the kind of thing I would've made had I been alive at this point. And I love how a few of the EEPROMS are just fully uncovered - be a shame if a little UV light was to come along!

That floaty wavey effect around 13 minutes in is so cool. can see an analog horror series using it

This is such a cool mutant machine. Good on you for spending the effort to unearth its functions to try and put it back to work. It sure feels like you're close.

With regard to EPROM uses. Ben Eater has a video where he replaces a ton of discreet logic ICs with a single EEPROM, and made a comment that any collection of logic ICs can be replaced by one. After that programmable logic made a lot more sense to me.

In the 80's most all of the circuit boards I built at work and home were wire wrap boards. You'd be surprised at how fast you can put a prototype together.

That thing was probably the reason for the estate sale.

This looks like it would control some scrap metal time machine in a apocalypse movie

That radio shack joke aged me several years when I realized they’ve been closed since before I graduated high school

BNC for video is not "old style", it is currently used in all pro video equipment.

Great video as usual - I love all the comedic touches you add to your videos, they really make them stand out!

Another amazing video! It's always a wonderful day when you post a new one, I love old tech and it's great to actually learn some more about what came before modern computers.

The multiple line garbage characters my attribute to sync signal issues and bad latches. Try probing with scope. The 0:08 😂😁 is a real problem to acquire old tech and convince that it is worth it. Cheers!!

This is super cool, I look forward to your progress and updates!

Aiii was so hyped for this video! Amazing love how you do your videos with funny intermissions but at the same just beeing so interesting and full of facts !

Welcome back. You and your videos are worth waiting for. Glad you are feeling better and the brain fog is abating. I really enjoy your videos and lmfao regularly at them. Your deadpan is fantastic.

Those green edge-connectors were the bane of HP repair technicians in the 1970s and 80s. The plastic expanded, causing the middle connectors to lose contact!

I love this channel so much. Fantastic content !

I am very happy you showed up in my recommendations. Wonderful video and presentation!

I am guessing that the "audio card" is the tape interface card.

I love your editing style so much, it's so simplistic but it gets me every time. Also, head n shoulders didn't help me as shampoo, it just made my hair greasier XD

This thing reminds me of some weird kitchen gadget nobody knows the name of anymore. Clearly it had some purpose, it was made for a reason, but nobody knows what it is, and the more you try to guess, the more you are confused.

I love old home built interesting computer-thingies. Unfortunately I don't have that much time for such things but at least I enjoyed watching you mess with yours!

With all of the unique early video generating homebrew type machines you've displayed, I'm surprised you had not yet encountered BNC before in a practical setting. Great delving into a one-of-a-kind homemade machine.

Yer videos are so great - we need to get yer subs way up!! I’m in; I can see how much time goes in, I’d love yer help!! Great job, thanks for sharing.

This reminds me so much of my own hobby computer life around 1975-1980 !

Great video, and great channel you got going on here. The editing is charming and you're quite funny.

That introduction is so good, I had to stop the video when it was over to come down here to tell you that.

It’s the This Old Tony of tech! Keep up the good work!

That thing looks cool. Glad you're feeling better.

that's a thing of beauty bud, and that's how this computing was done back in the day.

Dude... love this project / vid / thing..

I've seen a lot of old computers, and all that I can say thanks for a look at some very old and interesting computer hardware. The guy who put this machine together was a genius of his time!!

I took a TV and film production course many years ago, and I kept calling BNC cables BNP cables by mistake. omg those wobbly characters are sick, I could look at those all day.

If that guy were still around, he would think this video is awesome.

I've watched this video several times, still amazes me how you bring these old machines back to life. It is a real shame the seller separated the terminal and the computer, this guy obviously had his own way of doing things and having both would have been quite a treat :) I hope someday the guy who bought it sees your video and leaves some contact info so we can bring the two machines together again.

What an interesting machine! Thank you for showing it to us, even if you couldn't get it 100% working again. 🙂

I love your style man

I immediately thought “Don Lancaster-TV typewriter”. My misspent youth following Steve Circia’s Circuit Cellar in Byte mag happily wire wrapping a Zilog sbc then a 8051 sbc.

16:34: the top of the screen be vibin'

What a monster! It makes the "generative ambient modular" Euro-rack spaghetti set-ups that populate my home page look downright manageable by comparison.

this is really cool didnt really know about homebrew computers and terminals

These are the obscure @BenHeckHacks reverse engineering videos I love. Excited to see what the future holds for this project.

the intros to these videos are always hilarious

Great work something like this must be a bit of a nightmare to diagnose .

I envision a repair for that broken corner similar to how they fill in missing parts of fossil skulls.

It was unsatisfying not to get a successful conclusion to this. Still, I'm impressed by your technichal savvy, your sleuthing skills, your near-angelic patience, and, frankly, your courage. I hope you crack this nut.

Very entertaining and interesting. Thanks for sharing

Love your videos

I think, with the way the TV was acting, I'd drop a new crystal on there. That thing looked a bit sketch.

I can relate to the intro.. Another great video.

When RAM dies, it goes to the Delay Line in the sky...

Very fascinating. Thanks so much for sharing. 😉👌🏻

Your level of stick-tuitive-ness is off the charts.

essentially the benifits of homebrew from tyhe 70's. Even stored in the garbage pile it probably still ran up until you got it

That was very cool. Brings back memories.

I see a number of PolyPaks renumbered ICs. The big silver characters are the giveaway. Those were good days.

Thank you for this, it's very interesting.

My (non-expert) opinion is that this thing was either modified to over a long period of time to add more features, etc., or, possibly, it was a collaborative effort among several people. This would explain the multiple different circuit boards and overall bodged-together style.

This was fascinating

It's a shame you didn't get the computer this was made for. It's really cool though and really cool that you made so much progress.

Really enjoying the videos, thanks for taking the time to do them.. These are way better than going to a computer museum, because the act of you going through and figuring out how these things work is way more interesting and informative. Same reason I like CuriousMarc. Is that Radio Shack keyboard common enough still that you could just replace it?

Back in the 70s, microprocessors were expensive and ones able to execute meaningful programs almost non-existent. Hard-wired logic and logic design was both science and an art form. Far from just using bits and pieces lying around in the junk box, the designer would have gone to a lot of trouble to design this with all its video timing (sync pulses etc.) and it would have cost him/her a good deal. The machine was originally known as a dumb terminal (a display/input device) communicating with a computer via a UART-fed RS-232 interface. EPROMS were used for a number of functions in those days; specifically ASCII-encoding of a keyboard matrix, character-generation, a simple way of deriving timing signals from a binary counter rather than using a plethora of decoding logic and so-on. Erasable devices make bug-fixing, design modification and feature-adding easy. While the mains wiring is quite unsafe, I guess the builder never intended the unit to be used by others. It should never have been sold in that condition. I built such a terminal back in the early 1980's using a 6809 micro for doing all the smarts, a 6845 programmable video controller for generating the video timing signals, character memory addressing and so-on. Mine is in my study, is clean and tidy has all the smarts and video logic on a single PC board, the keyboard encoder on another and still works (uses the same keyboard as this one incidentally). The operating system for my terminal runs to 40 or so pages of commented 6809 code. I designed my own EPROM keyboard encoder and character generator and included a static RAM for programmable characters. Please do not be too disparaging of the efforts of early builders and hobbyists. I could say an awful lot in a similar tone about the disposable garbage that is built and sold these days with the sole object of making money. And these days I answer questions on another forum in the vein of, "how do I build a logic circuit to give a 0 output if A and B and ~C =1?", never mind the intelligence required to design something like "the Computer Thing From Hell". BTW the two main sources of problems you will run into with hardware built like this is poor IC pin to socket contacts caused by poor tinning on the IC pins, corrosion in the sockets, de-springing of the socket contacts themselves and above all, bead tantalum capacitors. I would replace all of the latter - they can short-circuit for no good reason at any time. They were often used for voltage regulator bypassing due to their low-ESR characteristics but modern miniature electrolytics with short leads will do the job just as well. And shorted power supplies in a system containing multiple-supply chips (like the old 2101s and other NMOS devices) can also cause chip failure. Taking time to scrape corrosion off the IC pins and applying good contact treatment to the sockets (or removing the sockets and soldering the chips in directly better still) can save a lot of trouble-shooting time in the long run. One last little thing: the wavy picture suggests that the picture tube yoke is being influenced by stray magnetic fields from a nearby mains-frequency power transformer.

Why it often looks like that people living in 110V countries are more hysterical about main voltage than those living in 220v countries? Yes, a fuse is something useful. yes the mains connection of that device is somewhat horrendous and covering it with electrical tape is recommend. but it's hardly necessary to make such a fuss about it. What would be really helpful and a much greater safety feature is having a GFCI breaker (residual-current circuit breaker / ground fault circuit interrupter) either in your home's circuit breaker box or seperate at your test bench.

Great now I'm curious and want to see a follow up

Those hand made breadboards are beautiful...

Thanks so much for making this video, any chance of some high resolution images of the front and backs of the various boards, it would be good to have a proper look and see what each board does. I hope you're recovering from Covid well, me and my family have avoided it so far here, but I'm sure I will get it in time.

Its a shame that the estate sale didnt keep the computer and the terminal together. That bothered me.

I have no idea of what i am watching, but i like the general vibes.

0:55 "But it's cheap!" "Yeah tell that to your divorce lawyer pal" LMAOOOOO

Yay a new TTT video!

Solder under strain or pressure will flow over time and break the connection.

I saw that power supply and I was like.. NOPE!

The garbage on the screen looks like some kind of alien alphabet. I think it would make a great movie prop for some kind of alien/post apocalyptic sci-fi movie :)

I like how the best way to describe it is as computer “thing”

Basically a modem terminal or a teletypewriter.

This video alone deserved a follow.

I love this thing.

as a person with schizophrenia, this is the best intro ever.

This computer is much better than all modern computers, no NSA spyware built in, no data mining, no ads, just pure computing

The connector was named the BNC (for Bayonet Neill-Concelman) after its bayonet mount locking mechanism and its inventors, Paul Neill and Carl Concelman. Neill worked at Bell Labs and also invented the N connector; Concelman worked at Amphenol and also invented the C connector. (Source Wikipedia)

I love jour videos

Absolutely love the content but sadly couldn't get past the 12:46 because of the horrible high pitch noise in the old footage; I am so glad you don't have that in your newer stuff. But keep it up; I normally don't comment but I felt bad I couldn't finish the video. ;w;

Very interesting!

Oh, memories. I built a video terminal using the same Radio Shack ASCII keyboard encoder back in 1979 so I could get online nights/weekends when the timeshare system had no other users. Amazing dialup MODEM ran at 300 baud, much faster than the Teletype we had at school that was 110. The rest of my setup were kits from Electronic Systems : a TV typewriter that was 16 lines x 64 characters, Power supply, UART board, RF modulator so you could run the video into a TV set, and a MODEM.

I love this intro

I literally just finished reading a chapter in a book bitching about the unreliability of those early intel ram chips, especially the 1103 apparently it was an enormous issue but the tech was so new that people tolerated them, xerox PARC built a pdp10 clone using the 1103s but tons of the chips were just junk on arrival.

apparently a lot of people skipped specifically to when the terminal's font was defined then that must be one popular font then

I use BNC connectors on a regular basis at work, to the point I have ~20 BNC barrels for extending cables floating around my car. They are a standard for ENG and live video production and can push up to 24GB/sec

All those chips with 7430 stamped on them... I'm sure I had some like that came which from bulk packs at Radio Shack when I was a kid. But I checked my old chips and didn't find any. I did find a pair of 7440 chips with no other marking than the big white numbers, though. With the other parts, it's clear that he got most of his parts from Radio Shack. I even used three of those same boards/connectors to try to make an 8080A computer back in 1979. (It would never have worked because I didn't understand TTL fan-out, or even testing a subsystem at a time.)