Working on the TI-99

[@UsagiElectric]

WARNING: There is a 15kHz whine from the CRT monitor in a few shots. Unfortunately, I have tinnitus and couldn’t hear it at all during filming, editing or even the final confirmation check. My normal lapel mic usually doesn’t pick it up, but in a few shots, I used a different mic, and it apparently picked it up very strongly. I apologize for this, I should have visually checked the audio waveform before uploading. On the plus side, if you can hear it, congratulations, you still have excellent hearing!

[@rickhole]

That will be from the high voltage power supply. The horizontal oscillator (which is working obviously) goes through a transformer and simple rectifier circuit to get the high voltage needed for the CRT. Probably over 10 KV. Anything loose in that circuit will vibrate as you hear. It con be windings in the transformer. At this point the monitor is no different from a color TV set from that era.

[@markpitts5194]

Join the club, didn't hear a thing. I used to think my tinnitus WAS the CRT monitor whines until one day i realised everything was now TFT or other flat, then it dawned on me.

[@amateurprogrammer25]

Thank you so much!

[@Colaholiker]

Don't worry, my laptop speakers don't go that high... ;-)

[@vwestlife]

Don't listen to people who whine about the whine. Anyone who is interested in old computers or video games will have to get used to it, just like everyone did for the 60 years or so when CRTs were in mainstream use. And p.s., you need to get a PEB!

[@alexandrsoldiernetizen162]

I was a programmer for a TI-990 based doctors billing consortium. Wrote COBOL during the 1980's. Machine did all the billing and various statistical reporting. All in all decent and reliable machine.

[@BOBXFILES2374a]

You did BILLING on a TI-99? Wow.

[@alexandrsoldiernetizen162]

@@BOBXFILES2374a Hmm, seems like you have trouble reading AND watching videos.

[@wushock92]

One of my bank clients ran a trust software package that only ran on a TI-990. Took us some training to run as we were a mainframe environment.

[@UsagiElectric]

That's awesome! Interestingly, I was actually shopping for a TI-990 when I found the Centurion minicomputer and went down that rabbit hole, but I would still love to get my hands on a proper TI-990 someday. They seem like really quirky machines that were actually decently capable!

[@UsagiElectric]

@@BOBXFILES2374a Alexander was working with a TI-990, which was a full on minicomputer. The TTL level CPU that was in the TI-990, evolved into the TMS9900 micropchip, which is the same processor that TI used in the TI-99/4 home console. But, despite sharing the same processor, the machines are very different indeed!

[@flounder31]

Always good to see the ole 99 here on KZbin, my first computer as a kid. Helluva sidecar collection, too.

[@UsagiElectric]

Thank you! It's a wonderful little system and I'm surprised more people haven't really gotten into them lately (especially as prices for Commodore stuff goes through the roof)

[@stevethepocket]

That's the most complete collection of sidecars I've ever seen. Wikipedia used to have a photo of every single one ever made hooked up like that, including one (I forget what it was) that was the exact same wedge shape as the computer itself. Unfortunately the photo was comically low-res, which might explain why it's gone now. If you ever complete your collection, you might want to think about getting a good photo and contributing it to the site.

[@WMidyette]

Could it be this? www.mainbyte.com/ti99/hardware/sidcar_computer.jpg

[@UsagiElectric]

Thanks! I think this is all the official TI produced sidecars that were available. There are two more, the Video Controller and P-Code sidecars, but they were never put into production. A few prototypes of the P-Code made it into the wild, but the Video Controller one never passed FCC regulations, so I don't think any were ever actually made. I do happen to have a spare RS-232 sidecar that I7ve been thinking about gutting and building a P-Code sidecar replica into. That would be really Interesting and get me one step closer to the ultimate TI-99 setup. The only problem is, I'm totally out of desk space, haha.

[@greenaum]

@@UsagiElectric A p-code interpreter is funny when you consider the machine essentially runs something like that anyway. It's litt;e 256-byte RAM running a virtual machine from the RAM in the graphics chip. It's an awful way of doing it really. Shame they couldn't share the RAM on the main bus. Have the VDP use graphics modes with less colours etc, to provide more spare RAM for the CPU. I suppose in the early days, it beat a bunch of LEDs and switches on your Altair, but it's a real shame such a powerful CPU was crippled and relegated in such a badly compromised design.

[@CaptainCattywampus]

Wedge shaped? You're probably thinking of the much later Hex-Bus Interface, which would have been the link between the 99/4A and TI's next line of mostly unreleased peripherals targeted for models like the very scarce 99/2 and unobtainium, like the 99/8.

[@kaitlyn__L]

You can usually still see the old pictures by looking in the page history, if it’s not absent from Wikimedia itself! There’s a ton of weird illustrations or crappy diagrams I recall from 07 or so, which are replaced by nothing or by fantastic photographs of the phenomenon in real life (probably putting the remainders to shame and hence nothing), but occasionally I go back to some pages I used to look at a lot (I don’t really remember why, guess I was just watching them for changes?) and laugh at those illustrations.

[@Taser3141]

My second time watching this vid. I smile every time time I hear the sound of the floppy drive. Such great nostalgia.😊

[@ibm3480]

You aren't the only one who gets excited for office programs. I absolutely love Script/Plus and Calc/Plus for my Commodore-16. They are still my preferred office programs, even today!

[@arongooch]

This channel is very quickly moving up my list towards my number one channel on KZbin to watch. Love your work and thanks for sharing it.

[@UsagiElectric]

Thank you so much!

[@cptsalek]

The TI99 with all the sidecars is a piece of art and great technology. Love it!

[@ralphwiggum3134]

Brings back memories. This was my very first computer and I remember writing simple programs in Basic and saving them on audio tapes (sounded like dial up modem noises). It was a great computer to start learning the basics.

[@UsagiElectric]

That's awesome that it was your first computer! My family didn't get into the computer world until really late in the game, so the first computer I ever played with was a 386 (despite having grown up in the 80s). I think it's really awesome how many people fondly remember the TI-99, I always thought it was an unloved system, but there's been a lot of awesome comments about it!

[@kevinmonceaux2101]

I have the same memories. A TI-99/4A was my first home computer when I was in junior high. All I had was the base unit and the TI controlled cassette player. I really wanted the expansion box with a floppy drive, but by the time my parents tried to get me one they were no longer available in stores. They ended up replacing my TI with a TRS-80 model 4, which I used through high school.

[@tex-hogger4974]

The TI99/4A was my first computer. My dad got the console for my brother and I for Christmas. We added a few carts and a subscription to Compute! magazine. Then we added the cassette cable and an off brand tape recorder. Game changer for me, I was then able to type in the programs from the beginner basic book, the Magazines, and save them. Then when TI got out of the home computer business my dad was able to get a PEB with the 32k card, Disk Controller, RS-232 card, and a SS/SD floppy drive. I still have the system stashed away in my stuff. I have been following the TI scene ever since. Still play around with the system in Emulation, and enjoy bringing back all the nostalgia. I stumbled upon your channel a few months ago and totally look forward to seeing what you put out. Keep up the awesome work!

[@UsagiElectric]

Thank you for the kind words! That's awesome that you got to play with a PEB! When I started with this system, I didn't initially know which direction I wanted to go with it, but when I was hunting for a CRT, I found that Sanyo and the person I got it from also had the thermal printer and an RS-232 sidecar, so that decided it. The hunt was on to build a 5-foot long computer, haha. I love hearing stories about people using these systems. Even though the TI-99 seems to be fairly unloved, I think once you got the hang of the system and had it kitted out pretty well, it was really a capable machine!

[@kencramer1697]

I loved seeing the old Ti-99. This was the first computer my family had at home. My father worked for Ti. We had a fairly basic setup, but my grandfather went nuts with his. He had about every add on to the Ti-99/4a you could get your hands on. I still had a ton of the stuff up until a few years ago. I donated 4 complete systems, a bunch of the expansion modules and a crap ton of cartridges to the 8-bit guy as he is here in the Dallas area as I am.

[@UsagiElectric]

That's awesome! My family went through the computer renaissance a bit late, not getting our first machine until the 386-era, at which point I missed out on all the really wild 8-bit systems that paved the way. Also, small world, I'm a bit south of the Dallas area, but do try to make my way to DFW retro computing meetups whenever I can!

[@lindoran]

Had no idea that the ti99 had direct mini-computer roots. That's fantastic

[@UsagiElectric]

There's lots of storied circulating about why, but I think the popular theory is that TI had a different CPU planned for it, but it wasn't going to be finished in time. So they slapped their minicomputer CPU in it, but they didn't want the home computer to compete with minicomputer sales, so they strangled it down to 8-bits. I'm not sure how much of that is true, but makes for an interesting story at least!

[@kaitlyn__L]

@@UsagiElectric it’s in the realm of plausibility, which is of course the most dangerous place for fiction to inhabit !

[@PeBoVision]

2 things I don't miss on my F18A equipped 4A: - Fidlling with composite out (or worse RF modulators) - Multiplan in 40 columns . I remain forever envious of your sidecar collection (especially the thermal printer). I love my PEB and all the cool 'n groovy new cards being produced, and I have a desk to small to accomodate anything wider than the firehose connector, I would so love to have all the sidecars on display with the system. Thank you for the always informative and entertaining content.

[@Artemis-zl5cs]

TI-99 as a centurion terminal emulator would be a really cool thing to see.

[@bascomnextion5639]

Or hook up a centurion terminal to the serial port of the T-99.

[@UsagiElectric]

I gotta use that RS-232 sidecar somehow! That's definitely on the list of things to do :)

[@ChrisPinCornwall]

I love your videos. I am sadly old enough to remember most of the stuff you work on coming to the fore. Thank you for what you do.

[@UsagiElectric]

Thank you so much! I remember some of the computers growing up, but my family got our first computer pretty late in the 386-era, so I missed out on all these excellent little 8-bit machines. But, I7m having a blast learning about these old machines and the quirky ways they were built!

[@andrewwasson6153]

Cool. I had a TI 99/4A in about 1983 or so. I had a subscription to the TI computing magazine which advertised all of the software and sidecars. I was 19 and had left home so the little money I earned needed to stretch. I had the video game Parsec and a cassette for saving and loading my basic programs. Thanks for the trip down memory lane.

[@GodmanchesterGoblin]

Loved this. I used to work on TMS9900 hardware in the late 70's and 80s and wrote assembler for both TMS9900 and the faster (3rd generation) TMS99105 (not to be confused with the 2nd generation TMS9995). I also designed a range of processor boards and related industrial hardware around the latter in the 1980s. I still have a bunch of the instruction mnemonics in my head, and possibly a few op-codes as well. Loved that NEC monitor too. I have a 9 inch version from the same period that still works, complete with scratchy volume control.

[@UsagiElectric]

Thank you! The TMS9900 is such an interesting chip, I would really love to see what it could do if it were completely uncorked and allow to work at its fullest potential. Maybe someday I'll have to build a homebrew system based around it. The NEC monitor was a pleasant surprise, that was truly my first time pumping a video signal through it, and man alive is it a gorgeous looking monitor. Really makes me want to get that PC-8001 up and going!

[@TechTimeTraveller]

Excellent video. That sidecar train is nuts! The intro makes for some pretty good ASMR also!

[@UsagiElectric]

Thank you so much! And I was just watching your homebrew terminal episode this morning! That thing is awesome!

[@mdouglaswray]

I LOVE that you have this dinosaur up and running!!! I used one of these eons ago and remember it fondly.

[@bumpedhishead636]

My brother bought a used TI-99/4A system to use at his pharmacy. It had the Peripheral Expansion Box (PEB), the memory expansion sidecar and a dot matrix printer. I think the accounting software was called DacEasy. The system also came with a shoebox of cartridges, including Extended Basic. You really needed that Extended Basic cartridge, the built-in Basic was very limited. I worked part-time at his store when I was in college, and I spent quite a bit of time playing Tunnels of Doom during my lunch breaks...

[@loginregional]

Favourite game EVER. Bahhhh bubahbubah baaahhh

[@UsagiElectric]

Interesting, I don't think I've ever heard anyone actually using the TI-99 in a proper business sense, but with the memory sidecar and the printer, it should be totally up to the task! I also have the Extended Basic cart and you're right, it's absolutely necessary, the built-in Basic is very bare bones. The Mini Memory cartridge is also a good one to have as well since it opens a lot of good avenues too, like assembly programming or using peek and poke.

[@acrinsd]

My first computer was a TI-99-4A. With the cassette deck for storing programs. Awesome little machine at the time.

[@UsagiElectric]

I agree 100%, they were excellent little machines and I'm surprised they weren't more competitive. Though, I suppose it all comes down to the software, and the Commodore folks had some excellent software out there. Still, the TI-99 is fantastic and has a very active community still developing stuff for it!

[@BollingHolt]

Lots of memories from that machine. When I was a kid, I had a CoCo2, and my grandfather had a TI-99/4A with the PEB before selling it all and moving to a PC. About 20 years ago I came across a TI-99/4 (before retro collecting was "cool"), and I hung it up on the wall for display where I worked. I think I left it there (as well as an original AdLib card that commands a hefty price now) when I left. I wish I had it back!

[@bluepen61]

I loved my TI99/4A. The Centurion book scene reminded me of the TI's Editor/Assembler manual. Thank you for sharing.

[@loginregional]

I was waiting for an explanation of the BULLWHIP command, Branch and Load Workspace Pointer...

[@bluepen61]

@@loginregional Assembly is difficult for me. My understanding: the 9900 doesn't have internal registers like 'common' processors of the day. The registers were in valid external address workspace. The workspace pointer set the workspace address for the registers to use. One could set the registers at address 1234 then switch to 2345 and use those, then revert back to 1234 and continue were you left off. Beyond this, workspace assignment could easily get very complicated. There wasn't much, if any, info about the 99/4A available at the time unless you were a TI developer. TI kept everything so secret and proprietary. I hope this helps.

[@loginregional]

@@bluepen61 Way back when, my friend Dave had the Minimem cartridge with which he successfully learned to program, eventually becoming a highly paid programmer (on other processors, of course). I went whole hog and got a PEB Good luck with the Centurion. And the Counterfeit

[@UsagiElectric]

Thanks for checking the video out! On the topic of the external workspace registers, that actually seems to be a fairly regular thing for minicomputers I think. The Centurion has multiple interrupt levels with each level containing the same 8-registers, so you can change to a different level on the fly and whatever was being worked on previously is preserved exactly as it was. With the Centurion, there are 16-levels, which means there can be 16 CPU interrupt requests coming in simultaneously and the machine can just sort it all out. The TMS9900, being a minicomputer processor, is probably aiming for the same idea, so multiple users can be using a single machine, sending interrupts and getting responses back all simultaneously. Multi-user computing of the 70s and 80s is really, really fascinating stuff!

[@BasicBitesCA]

More sidecar than computer... wild! Something to consider: when it comes to heat-sinking RF shields on these old computers (at least in the C64/128 world), I've come to use 2mm thick thermally-conductive silicone pads rather than thermal grease. They squish down nicely to form a good seal, especially where potential bending of the shield can cause "gapping" that may otherwise need to be filled. -- JC

[@UsagiElectric]

It's so hard to find enough actual physical space for the machine, but I think that's what I love most about it, haha. Good call on the silicone pads, I never thought about that, but it's a much nicer solution than the boat load of thermal paste I used!

[@TheVintageApplianceEmporium]

What an incredible TI99 set up! I had one back in the 90s (just the machine, no sidecars) when they were cheap and disposable. It's one of the many machines from back then that I wish I'd kept. Along with an Exidy Sorcerer and an EACA Colour Genie! Oh it makes me sick to think how rare / valuable those computers are today :(

[@UsagiElectric]

Thank you! The TI-99 is still relatively cheap to find on eBay. Granted, that's just the base system wit ha most likely thrashed keyboard, but it's certainly one of the more affordable retro computers out there!

[@SeanBZA]

Tip for that TI99 is to grab an old CDROM or DVD drive and strip it for the thermal pads from the PCB, which will make for better heat transfer to the heatsink, and those importantly do not dry out with time, and make really good heat transfer and gap filling. They also can be placed on the TMS9900 CPU, and the other big chips, as well, extra cooling can only help. Plus change all the electrolytic capacitors as well, the 40 year old ones are only going to fail, and with the extra load of the sidecars you want the best ESR on the existing ones. Yes radial in place of the axial works, and as a bonus use Nichicon ones, using the next higher voltage ones in the skinny case, gives a closer look to the originals, Sleeve the lead, not the case, as you do want the case to either be isolated or only touch the negative lead, as the case otherwise becomes a separate poor leaky capacitor.

[@frankowalker4662]

Loved the openning film. LOL. Nice monitor fix, but it's a good job you did open up the TI-99 to get rid of that crusty cap and fix the monitor socket. Cute kittens. :)

[@UsagiElectric]

Thanks! I had a lot of fun filming that one! Yup, I probably could have gotten the video looking decent by just working on the monitor, but it was a good thing I found the broken socket. Still lots left to do on it, but I'm pretty happy with where it is now!

[@video99couk]

I remember making the choice between VIC-20 and TI99/4. Cost was a major factor but also the amount of software and hardware available. There seemed very little interest in the TI machine in magazines of the time, so I went with the VIC-20. I still have it and it still works.

[@UsagiElectric]

Oh yeah, at the time I think the VIC-20 would have hands down been the better choice! The TI-99 is a surprisingly capable machine, even with one arm tied behind its back, but TI never really opened up the software market to 3rd party developers, which really hurt the software side of it and never really allowed the machine to take off. I think if the CPU had been uncorked and allowed to stretch all 16 of its bits and if they stuffed 64k of RAM into, they would have had an absolute screamer of a machine!

[@video99couk]

@@UsagiElectric And since it ran on dynamic RAM, 16k wouldn't have cost as much as it did with SRAM machines.

[@BenjaminMaggi]

TI fan boy here, you've got quite a collection of TI instruments, thanks for sharing, you're a great creato!

[@UsagiElectric]

Thank you so much! And I'm a bit of a TI fanboy too! I was actually shopping for a TI-990 minicomputer when I stumbled across the Centurion, which was so cheap I couldn't pass up on it. I've still got my eye out for a good TI-990 though, someday I'd love to have one!

[@tomy.1846]

Love to see my first computer still out and about! Loved that little computer. :)

[@silitekmodder5681]

I'm designing a replacement keyboard for the 99/4a and I had the same issue with the top row keys too high up . Maybe I made a mistake measuring the original PCB but the issue seems to be mostly resolved when I 3D-printed some spacers for the screws.

[@paulawillaminachandler-ren3725]

OMG! I know of a few channels here that would have made this a multi-part series with 40 minutes per episode. This was so amazing. I am seeing the Ti99 in a new light too; because I always hated that machine. As an animal lover [NO Birds] When I see kittens, I am like "Go right back where you came from Right Now!" When you have 9 grown you'll understand.

[@UsagiElectric]

Thank you! I try to keep all my videos right around the 20 minute mark, but I still have some multi-part series because I simply couldn't finish the work in time. I'll probably revisit the TI-99 again in the future to work on the printer and test out the rest of the sidecars fully. It's such a quirky little machine and the more I learn about it, the more endearing it is, but man I would have loved to have seen a machine that fully uncorked that TMS9900 and let it stretch it's full 16-bit wings! Three kitties is the most we've ever had at a single time! We live on a farm and these three are going to be our outside cats to help keep rodents and snakes away. They're way too small for the moment though, so we're keeping them in the garage until they're big enough to properly hunt!

[@laustinspeiss]

I remember one of my best friends had a 99/4 and loved it… I was never won over… my direction was Z80 and onward. i was intrigued, as a product manufactured by the chip manufacturer (TI).

[@richardhaas39]

TI also manufactured printers, watches and a dual cassette system that was intended to have car dealers as customers. And, as far as chip manufacturers making final products Intel made a server that ran Interactive Unix and was used by stockbrokers.

[@jamesthompson7694]

Man wouldn't you get a kick out of the fact the were also a weapons manufacturer

[@UsagiElectric]

I feel a certain bit of pride towards TI since I remember driving right by their Arlington plant when growing up. I'm probably a bit biased being a native Texan, but the TI-99 is really interesting in that it's essentially a choked down minicomputer. I can't help but wonder what that little TMS9900 could do if it were uncorked!

[@richardhaas39]

@@UsagiElectric The Quotron 801 which features in the movies "Wall Street" and "Pursuit of Happiness" was an eight bit machine (it was never referred to as a "mini-computer" by either the users or the manufacturer) that was built around a TI CPU and ALU. It ran machine language. The upgraded machine, the Q1000, ran Unix and was based on Motorola 68000 series chips. The Q801 was still being installed as late as 1991. Chips had to be sourced on the "grey market" as many of them were no longer being manufactured. A machine running machine language is going to be faster than one running an operating system and traders preferred it for that reason.

[@ronhutcherson9845]

I love the sound of that keyboard. The one I used was a great typer. Seeing all the pieces in that chain, I appreciate the PEB I had even more.

[@Motocicleiros]

Very cool! Here in Brasil the most popular micro-computers in the beginning of this era (1980s) were the Sinclair and therefore I started with a TS-1500 clone in 1983 and right after, in 1984, I upgraded to a TS-2068. At that time personal computing magazines imported from US were very popular in technical bookstores. As a poor need teen I remember to go to these bookstores with my friends just to keep browsing it and dreaming about computers I never would have ~ and yes, the TI-99 was one of my favorites. Unfortunately I never had the chance to get close and see a TI-99 for real and the maximum I had of it were pictures in ads and articles. Videos like this are a rare opportunity for me to get a differentiated view of it. Thank you!

[@pipkinrahl7264]

This was my first computer. I still remember recording my programs to audio cassette.

[@UsagiElectric]

I love seeing so many people that had the TI-99 as their first computer! The tape deck is one of the few accessories that I've been waffling over getting. I actually have some software that came with a tape, but with the disk drive, it just feels like the Disk Drive is the better option.

[@grumpyoldmankew]

In the late 70s and early 80s, I was a TMS 9900 assembler programmer. I absolutely loved the 9900 it was so clean and uniform with its 16 wonderfully general purpose registers, such a contrast to the myriad of special purpose registers that Intel were so fond of. The company I worked for had great success selling its data communications equipment that shipped with vast quantities of TMS 9900s. When the Motorola 68000 came along it had the 9900s beautifully clean simplicity and of course the registers were all 32 bits instead of 16. It was an assembler programmers dream come true. In my opinion Apple did the right thing choosing the 68000, imagine how the computer industry would be now if only IBM had done the same.

[@UsagiElectric]

Whoa, that's awesome that you actually worked with the TMS9900! I bet it was a really great CPU when it was not bottlenecked by the VDP in the TI-99. The more I learn about the TMS9900 the more familiar it feels compared with the Centurion. Granted, the Centurion uses an 8-bit data bus, they both seem to have a strong focus on a lot of flexibility with the general purpose registers and really geared towards multi-user setups. I would love to build something with the TMS9900 someday as I think it's a wonderful little CPU!

[@SeanTurnerDeeper6]

I used to drool over the 8"disk expansion and voice synthesis. They were a lot of coin in 1985! had to deal with the cassette tape for storage.

[@UsagiElectric]

The disk drive I got in a righteous deal from a fellow TI-99 enthusiast, and with it and the 32k memory expansion, the TI-99 is a surprisingly capable machine, despite having one arm tied behind its back!

[@sbfotome]

I still have my ti-99 with the cassette drives. I have not fired it up in years, but it still looks new.

[@terrencewalsh453]

Got a bunch of parts for the TI-99A in the attic for years, unfortunatly I scrapped the expansion box back in the 90's!

[@BOBXFILES2374a]

I think this was the first "computer" that I bought, back in 1985. Beige. You obviously have the cool, chrome "business" model, with a key-lock!

[@Chekolynn]

Hola. Linda Texas Instruments PC Retro :) Es normal que empiecen a fallar esos sistemas retro, pues tienen ya casi o más de 50 años! Pero cuando funcionan al 100% son una maravilla, pura nostalgia amigo! Saludos desde la Ciudad de México.

[@UsagiElectric]

Thank you! They are really great computers, and the TI-99 seems to be quite tough given its age! ¡Gracias! ¡Son computadoras realmente geniales, y la TI-99 parece ser bastante resistente dada su edad!

[@johnhelt5475]

I love all the sidecars!! I thought my PEB took up a ton of space, but you take the cake.

[@winstonsmith478]

Fascinating. I didn't know that mini-computer history of the CPU. I bought a TI-99/4 when they were being discontinued for $99 just to have a that CPU to play with. Now, I deeply regret not keeping it along with all of the many other now "classic" computers I've owned.

[@mmille10]

Even though I don't know electronics that well, I enjoyed this. I'd heard for years about how expansion worked on the TI, and finally got to see an extensive expansion in your video! Wow! I pictured the setup would look like this, all strung out to the right of the computer, but to see you have to turn on a bunch of them before turning on the computer was a trip. I was surprised to see the TI floppy drive as its own module. I knew a floppy drive was available for it, but the one I remember was part of a huge expansion module, which I think had a bunch of card slots in it. I thought that was the only way to get the disk drive. Owning an Atari 8-bit computer, I was used to having to turn on the monitor/TV, and the disk drive before turning on the computer, but that was it. My freshman year in college (1988), I had a roommate with a TI-99/4A. He had only a couple sidecars. One was the voice synthesizer (a classic), and a reasonably-sized interface module from a third-party manufacturer. He connected this up to a dual disk drive module through a ribbon cable. The drive was, again, from a third-party. And he had a third-party phone modem hooked up through the RS-232 port on the interface module. As I remember, he made his own detached keyboard by removing the keyboard from the case, and mounting it on a board, with the ribbon cable from the keyboard stringing up to the case.

[@Keonyn]

Brings back memories. Growing up my friends parents had a TI-99. Now this was already in the era of the NES so it was more of a novelty but it was still fun to play on. I remember many a day of "Hunt the Wumpus" on that machine. Of course they only had the base unit, none of those sidecars.

[@kencramer1697]

I too have spent many a day on "Hunt the Wumpus" along with Tunnels of Doom, Parsec and Munchman

[@UsagiElectric]

I really, really need to play Hunt the Wumpus! I have all sorts of productivity software for it, but no games at all. I should definitely grab some of the top class one and give them a go someday!

[@kencramer1697]

@@UsagiElectric Reach out to The 8-Bit Guy Here on youtube. I donated a ton of cartridges to him along with disk drives, tape drives, 3 or 4 complete systems. He may have several doubles of things. Heck you two might even be able to set up a collaboration video.

[@MiriOhki]

Had a C-64 here, but the elementary school I went to had a couple 99/A4s. Played a lot of hunt the wumpus and number munchers

[@rubbersoul420]

@@UsagiElectric You should try Parsec, that was my favorite game before we got a NES.

[@acceler9]

"Well that's an interesting point I've gotten to in my life..." Hahaha, so true for many of us! I have so many fond memories of my TI-99/4A back in the late 80's!!! Thanks for bringing that felling back some.

[@Raul_007]

Great video. The ti 99/4a was my first microcomputer! Beautiful kittens.

[@BarnokRetro]

In the 70s and 80s I could hear a tv whine anywhere in the house. Today... well, not so much.

[@UsagiElectric]

I'm sure I could hear them as a kid, but I can't remember the last time I hear flyback whine. I think that just tells me my ears have been bad for a long time, haha.

[@jameshughes3014]

As a kid whos first machine was a TI994a, it did an absolutely amazing job at teaching me that i should get a better computer .. but, That was kind of its purpose, to get people who've never considered owning a computer to buy one for the first time. Price was the single important factor.

[@AltimaNEO]

Had one of these as a kid around 1990. Good that thing was outdated by then. But it was the only computer I had ever touched till that point. My dad found it on the side of the road one day. We only had a few game cartridges, and I enjoyed playing them, but ultimately they were way too simple and we'd get bored. Eventually the monitor gave out, the original Texas Instruments monitor, and my dad threw the whole thing away.

[@UsagiElectric]

Oh man, by 1990 it would have been crazy outdated, almost retro, haha. The TI-99 suffered from pretty poor software because TI didn't want to open the software market up to third parties, so it just kind of languished. Since then, the homebrew scene has made some pretty amazing stuff run on the hardware, like a full-on 3D ray tracing engine, which is just staggering. I really would have loved to have seen the TMS9900 in the TI-99 uncorked with a boat load of RAM and full use of its 16-bit data bus, I think that thing would have rocked!

[@aribertcarsten]

Thanxs a lot showing me all the stuff I dreamed off back in these days. My very first computer I got as xmas-gift in 1982 just with a casette player after finishing my time in school.

[@edgeeffect]

I always wondered why the '99 had such a (gotta say it) bizarre architecture... but it having it's roots in a minicomputer kinda explains some of that.... never heard the full story before, and I was around when this machine was mostly being ignored in the shops back when all the kids were gathered around the C64. That intro was excellent... I love to see tech channels flexing their dramatic script writing muscles. ;) Also that is THE MOST well equipped TI-99/4a setup I've ever seen..... it's gorgeous!

[@UsagiElectric]

Oh yeah, it's a really interesting and powerful processor barely trundling along in a compromised architecture! The intro was a ton of fun to film this time, I'm really enjoying these little short films, so I think I'll try to work more into future videos. Thanks for the kind words on the system! It's almost fully equipped. There's just two more sidecars that I don't have, but both (the Video Controller and P-Code cars) never made it to production and only a few prototypes survived and made it into the wild. I've been thinking about taking my spare RS-232 interface sidecar and building a proper P-Code replica, but I'm all out of desk space!

[@edgeeffect]

@@UsagiElectric the P-code sidecar sounds very interesting.... in the UK the 99 wasn't really much of a thing.... so it's all quite new to me.... is this anything to do with The UCSD P-System? I did a little bit with UCSD Pascal at college so, when Java came along I was all "oh - just a rehash of The UCSD P-System"

[@qwkimball]

Thanks so much for this. The TI-99 4/A was my very first computer, which went to college with me in 1983. All my programs were on cassette tape. Did it impact my life? Yesterday, I finished an i5-12600K build after GPU prices returned to more sane levels. I didn't take up a tech career path, but PCs have been a hobby of mine since I first got this little gem.

[@UsagiElectric]

Thank you for checking the video out! Having grown up in the 80s, I didn't build my first computer until the 386 days, so I love hearing stories about how people interacted with all the different 8-bit machines I missed out on growing up.

[@HeyBirt]

The TI-99 smacks of being the brain fart of the marketing department. "We need a personal computer now! We're not using that 16bit thing, slap it together and make it cheap, by yesterday or sooner!" All the work to kludge in that processor killed it...

[@drussell_]

They had a microcontroller-sized version in the works that simply wasn't ready by the time they wanted to produce the TI-99/4, so they just used what was already in production, the TMS9900, with the thought that they'd increment to a cost-reduced hardware release later, but the bottom fell out of the market before they ever got that far along and just abandoned the whole home computer market.

[@UsagiElectric]

I think drussel nailed it, they just rushed the product to market but it wasn't quite complete, and that killed them before they even got started. Around the same time, TI was absolutely mopping the floor with every other competitor under the sun in the calculator market, so the higher ups probably made the decision to axe the computer division and focus on the real money maker.

[@defaultroute]

@@UsagiElectricI remember that the marketing was top notch. The cartridge and cassettes looked premium and akin to a ‘Nintendo’ experience. I mean, quality cardboard and plastic. They put a lot into presentation. As far as I knew the issue was Commodore and their race to the bottom discounting that killed the Ti.

[@kingneutron1]

Man this takes me back... We had the TI-99/4A with the hardware speech synth, Extended Basic, Parsec, Alpiner... I was able to make some hardware sprites and put them in motion, even programmed a text-based Voltron game. We had to save to an AM/FM radio cassette deck and thought that was The Shit back in the day!!

[@UsagiElectric]

That's awesome that you programmed a text-based Voltron game, that's like the most 80s thing I can think of, haha!

[@GoogleSpyZon]

That keyboard sounds amazing... and that system is pretty neat.

[@UsagiElectric]

I love me some proper old school mechanical keyboards!

[@cb-gz1vl]

Loved the 9900 chip. Only 3 hardware registers cause you could map any 16 word mem area as the working registers. And lots of operations were memory to memory.

[@scottjohnson5415]

The TI 99/4a was the firm home computer that I purchased. Mine had a regular keyboard, not a membrane keyboard. I didn't have any of the sidecars. I had a cassette recorder to store programs.

[@NullStaticVoid]

One of the first computers I ever got to use. Right after the local Radio Shack's TRS80, which I learned to program on by just hanging out at Radio Shack. Went to a computer camp when I was about 10 and the main lab was all TI-99/4A. There was a smaller lab with Apple II and a few Pet CPM. I though it was a fantastic computer. Probably dazzled by the very 80's industrial design. Begged and pleaded to get one for my birthday, but we ended up with the Atari 800 instead. A wiser decision, since I didn't need a 12 foot long desk to fit all the peripherals. The Atari using CABLES instead of a card edge buss. Also the Atari had a much more robust user community.

[@2011joser]

I always remember my and several of my friend’s frustration at missing out on these computers. One year in highschool we all signed up for a brand new computer class. We were all set to buy a commodore of some type when one of the group said his aunt in texas worked at Texas Instruments and could get us all a great deal on the Ti’s. Needless to say, there was no computers coming from the aunt and those who stayed in the class got to work on Trs-80s.

[@UsagiElectric]

TI's story with the TI-99 is an interesting one. It has so much potential hiding away inside it, but it's strangled by the 8-bit VDP, lack of RAM, and TI's decision to not open up the software market to 3rd party devs. In the end, they could barely give the system away, which is a total shame. Having said that, the TRS-80s y'all got use in class were probably much better performing machines, haha.

[@2011joser]

The Trs 80s just weren’t cool at the time but they were good enough for the class. The cool kids called them “trash 80s”.

[@KameraShy]

I am astounded that the old floppy diskette is still readable. Maybe a backup copy?

[@UTubeRangerBob]

That NEC monitor is almost exactly like the monitor for the HP86B right down to the scratchy volume knob. The only difference is the HP has the power jack on top and the I/O jack on the bottom.

[@AjinkyaMahajan]

Those kittens are awesome

[@ropersonline]

So basically the sidecars are, from left to right: (1) speech synthesizer, (2) printer, (3) 32K RAM expansion, (4) serial port [w/ acoustic coupler and possibly modem on top], (5) floppy controller, and (6) floppy drive. Did I get that right?

[@UsagiElectric]

Yup, you nailed it!

[@PeterRichardsandYoureNot]

I loved my ti-994a and it’s speech synth, with sprite support, expanded basic, etc. the save to tape was annoying as heck…but a great simple machine to work with.

[@UsagiElectric]

Extended Basic really woke the machine up to! I think a lot of people judge based on the original Basic ROM included and it's not the best Basic out there. Coupled with the slightly unfamiliar syntax, I can see it copping a lot of hate, but with the right accessories, the TI-99 was a great little machine!

[@stefanegger]

1.) It's always like that "it did work before". If it would not be like that, it technically would not have gone broken. 🙊 2.) it needs all those things, like 3 meters of expansion, and can't even match a C64?!? I do not have any expansion for mine but I guess yours is not in the category of a "mini computer" any longer🤣 3.) I miss the bunny 🥺

[@ethanpoole3443]

In fairness, a stock C64 did not come with a printer, acoustic modem, or floppy drive either, so it isn’t an entirely fair comparison. But it is certainly an unwieldy system if one has more than a couple expansion devices. I much prefer using cables (like the Commodores) than needing to have every device rigidly chained together! I was never terribly impressed by the TI/99 back in the early 80s as even my early Vic 20 was a nicer system to actually use than the awful membrane and chiclet keyboards used on the TI/99.

[@PeBoVision]

SO jealous that you have a TI-thermal printer. It has been on my wish list for 40 years. In '82 it was out of my snack bracket (having just bought a decked out PEB), and nowadays they are impossible to find in working condition (and I lack your repair skills in such matters). I did muster the courage to replace the VDP with an F18A though, and so I can use the 80 column version of Multiplan (eat yer heart out, you and your fancy-pants thermal printer!) Fun video. Earned you a subsscription (full diclosure: 4A content usually does that).

[@TornadoCAN99]

Loads of good memories from my youth! I had the "chiclette" keyboard 99/4 and then the proper keyboard 99/4A. Space Invaders, Parsec ("Nice shot pilot!"), Hunt the Wompus! Never had the full complement of peripherals like you, though I worked all summer selling vacuum cleaners to splash out for the PEB (Peripheral Expansion Box)...though I can't recall what I actually put into that :-)

[@UsagiElectric]

Oh man, color me jealous! I've been on the hunt for an original chiclet keyboard 99/4 for a while now, but they're super rare and insanely expensive when one does pop up. That's awesome that you upgraded to a PEB though. The PEB is such a good idea for desk space, but I do think the ridiculous train of sidecars is certainly more fun to look at, haha.

[@thedogwooddandy]

That NEC character display is very resilient. I also have a premade spreadsheet with all the internal capacitor values including the audio daughterboard inside if you ever want to top-to-bottom recap that baby. It's the crown jewel on top of my Apple II+ and what I use for my own home built Z80 system. Love your work.

[@sprybug]

I used to have one exactly like that. Was a great green monochrome monitor with a nice crisp display. Wish I still had it!

[@solid-state]

You were lucky with the shielding (or maybe I was unlucky), my TI-99's shielding was soldered to the mainboard ground plane in multiple points, it was a pain to remove.

[@UsagiElectric]

Ooof, I don't think it should have been soldered, but I can definitely imagine how that would be an absolute nightmare to remove!

[@clydedenby1436]

I've got 3 main CPU's which I scored at two different thrift stores on the same day. All three work beautifully and I fire them up anytime boredom sets in.

[@RinoaL]

I have a TI-99-4A that I got at a thrift store in 2008 or so, but unfortunately I never found a single piece of other TI-99 hardware so it's kinda useless to me. Maybe I should send it to you along with the other stuff.

[@UsagiElectric]

Finding a TI-99 in a thrift store is a nice bag! Is it one of the earlier black and silver or later beige models? Either way, there's some excellent ICs in there if you ever feel inclined to salvage the pieces out of it!

[@Mike-B-Jackson]

Oh man, this brings back SO many memories of Hunt the Wumpus and Alpiner

[@alerey4363]

I'm curious about how the 9900 processor falls into the "16-bit" category just by having a 16-bit address bus? I thought the defining "wide" of a micro was the size of its internal registers, or how many bits at once it can move internally/externally (not to how many memory addresses it can read/write). If you apple the address criteria shown here then the C64 is also a 16 bit computer. Also I wonder if someone would be able to re-design the TI 99/4A getting rid of the ridiculous bottleneck and unleash the real power of the processor, not having to be restricted by the non-existent 256 bytes of memory and going thru the VDP for every operation, rendering even a basic listing to a molasses speed.

[@UsagiElectric]

The TMS9900 actually does have a 16-bit data bus! The machine is hobbled by the fact that the memory is all gated by the VDP which only has an 8-bit data bus. So, the TI-99 is technically a 16-bit system, but practically it's just an 8-bit system, since all memory read and writes happen 8-bits at a time. For the high-speed SRAM that it uses as scratchpad memory, it can actually use the full 16-bit data bus, so internal register operations should be fairly quick!

[@TheSulross]

an older brother bought a TI-99 for himself and bought a Commodore 64 for me - years later finally understand the architectures enough to see that I got the better architecture design as the TI direction of CPU design was avdefinite dead-end given the evolutionary trends. Not speaking from market place perspective but technical perspective. The TI's clever way of using memory to store context switching state would become more problematic as CPU clockspeed and memory clockspeed would diverge further and further apart.

[@UsagiElectric]

I don't know if I would say that the TI-99 CPU design was a dead-end so much as it was designed around different concepts. Minicomputers using similar architectures were used well into the mid-90s (the Centurion minicomputers were used regularly as late as 1995) because they were brilliant at data management and multi-user setups, something a 6502 or even the 8086 couldn't quite match. But, for a home computer / personal computer setup, that minicomputer architecture really didn't translate well at all.

[@BonesFPV]

I love your fully expanded TI.

[@Christianpreaching]

That special RF shielding is probably what gives it such a nice, crisp picture. Unfortunately I can't say the same about all other computers and consoles

[@orinokonx01]

I've got a TI DS990 Model 1, which I've been trying to get up and running for a few years now. It's loosely based on the TI990 series of minicomputers. It's kind of like TIs answer to the Commodore PET, if the TI99/4A is their C64!

[@BeigeAlert]

Oh wow! The NEC PC-8001 was my childhood computer back in the day! Don't see a lot of them!

[@vivanecrosis]

Okay, so that white stuff on the chip was dried thermal paste! I found 2 X Ti99 in the garage covered in muck and water. I cleaned them up and one of them works but the picture is garbled. Next I’ll try some new thermal paste on the video chip and then out the rf shield back on. Thanks, this video helped.

[@Trishlicious]

My second computer was a Ti 99/4A; had it for some time; frustrating for a 13 yo to know what computer was good those days. Eventually got a C64 and was all the better; the Ti had little support and not many affordable devices at the time. Wow, good to see one working again. Parsec was my favorite application. :)

[@BOBXFILES2374a]

Adding components , ie, sidecars with a click was a really great idea! Early "plug and play?" At the time, I had no idea accessories like this were available. Beats trying to get early Windows to "recognize" a printer, huh?

[@UsagiElectric]

The sidecar idea is really cool! Each sidecar has its own individual power supply, so you don't have any power distribution problems, and I believe each sidecar had direct access to the Address bus and Data bus. Though, they did tend to get a bit long, haha. Fortunately, the PEB, Peripheral Expansion Box, collected them all up in a nice little box the monitor could sit on for a much more streamlined desktop. But, I still prefer the massive train of sidecars, haha.

[@TyroneDeise]

15kHz... now, that's a frequency I've not heard for a long time.

[@UsagiElectric]

Sorry about that! I still can't hear it, but I should have checked the audio waveform before publishing. Interestingly, neither my wife nor my father could hear it either, guess that means we're all getting up there in years, haha.

[@TyroneDeise]

@@UsagiElectric oh… I can’t hear anything above 8kHz anymore.

[@EdwinSteiner]

It's a nice change to see someone use office software on such a machine. Games are way over-represented in the retro-computing scene. I'd love to see more about the old (home) office/productivity uses and especially industrial uses of the 8- and 16-bit computers.

[@finkelmana]

Lol. I just ordered two 99/4a's last week and waiting for them to arrive

[@johnchase7667]

I still love my TI99 and program for it when ever I can find time.

[@shepherdosterompton]

vintage computing and kittens? easiest sub of my life

[@UsagiElectric]

Thank you! These three little fluff balls will be making guest appearances in the future!

[@jorgeferreira6727]

What is the model of that TI pocket calculator? I still have a TI-58C, that was my faithful companion trough university, laying around, and your videos are making me feel like revisiting it.

[@UsagiElectric]

It's a little TI-Programmer that can do hex, octal and decimal operations! I have a short little video of putting a LiPo in it that I did a while back: kzbin.info/www/bejne/Y3yZq2RroMarqbM

[@LanceHall]

Yes! My first computer. If only it could have been designed in such a way as to fully take advantage of the 16 bits instead of being hobbled from the beginning. If possible someone should redesign it from the top down and produce a better layout that makes it work like it should have but still uses the same and/or vintage chips. Hobbyists have produced MUCH faster Extended Basic code and assembly routines.

[@BOBXFILES2374a]

My first computer, too! I had a speech module, and played it for my Aunt. She wasn't impressed. (1985)

[@UsagiElectric]

It's a great little computer, despite having one arm tied behind its back. I would love to see what the little TMS9900 16-bit CPU could do fully uncorked! That would certainly be a fun little homebrew system to build someday.

[@peterbelanger4094]

If only floppy drives were more affordable. I had one of these when I was a kid also, in 1984, No sidecars, just a cassette drive and a used rack mount monitor my dad got from work. I was an impatient 14 year old, I got bored waiting 45 minutes every time I wanted to save my programs. I did write a few, but cassettes are terrible for data storage. I wanted a floppy drive so badly, but my folks couldn't afford it. They didn't understand the importance of the technology and thought they were just getting me a toy. I didn't really get back into programming code for another 15 years.

[@joel530johnson2]

The first computer I had was a TI 99/4A. Later I got a job as a programmer/manager using a TI 990. That system was used to pay a 600 person payroll each week.

[@B9M3]

I'm surprised that these things ever had any use other than hobbyist toys, even when new.

[@joel530johnson2]

@@B9M3 The TI 990 was a "mini" computer about the size of a refrigerator. We had about 12 terminals in 3 locations. The payroll software came from a company in CA using RM Cobol.

[@cbmeeks]

So lucky! I wished I had those side cars. I got a PEB and some internal cards but wow.

[@kellingc]

What was that ASTATIS D104 hooked up to? Wouldn't a database program be more suited to the need (I know, spreadsheets make easy table designers) Awe, kitties.

[@UsagiElectric]

Nothing at the moment, it needs a full restoration, but I'm hoping to someday use it for some period correct recording (along with getting a vidicon camera). That's in the "very long term" category though. And a Database program would probably be much more well-suited, but I was honestly just looking for an excuse to show off Multiplan, haha.

[@KeritechElectronics]

Beauty and joy for ever! Excellent find and fix. Now let's check if it will run Doom... :D And kitties

[@VandalIO]

17:30 Why don’t you hookup the rs232 to an arduino ? Instead of bringing out the big gun( centurion terminal)

[@stheil]

Probably the same reason he went to his TI-99/4A to do some spreadsheets instead of his PC ;)

[@OmegaTI]

Did you know there is an 80 column version of Multiplan for the TI that works with the F18A VGA upgrade?

[@curtwuollet2912]

Pre IBM PC, how many people were sent down the path of writing machine code, assembly code and working " close to the metal". Now for so many, if there isn't an icon for it, it can't be done. I think it's a loss.

[@GKeithParish]

Man, what a fabulous throwback! Thanks.

[@Oddzball3]

Great intro. Your videos are top notch as always

[@UsagiElectric]

Thank you so much!

[@notneb82]

Ever consider getting the PEB? There were recently some NOS ones being sold on Ebay, I picked up one of them in November.