Upcyling a 40-year-old Tandy Model 100 Portable Computer | Hacker News Reader

Upcyling a 40-year-old Tandy Model 100 Portable Computer

spectrum.ieee.org

150 pointssohkamyung47 comments

I have a special place in my heart for these. In the past couple years, I acquired a perfectly-working Model 100 for $40 off Craigslist and a Model 102 for a bit more from one of the founding editors of MSNBC, who used it in his 90s journalism career.

This book is great, btw: https://archive.org/details/HiddenPowersOfTheTrs80Model100

It's nice that the Tandy's haven't seen the kind of price escalation that's affected other computers of the same vintage, especially compared their original price!

Related: This was posted on HN a couple of years ago. It's a journalist's story about using one of these, and includes the source code for the TRS-80 Associated Press program:

https://wayne.lorentz.me/computers/trs-80/this_trs-80/

i also have one deepmemeory even never seen it in real life. i heard about in byte and most likely from the guy who use s100; chaos mall sorry forget the column now. the last programming project of bill gates.

I own one of these. My first computer was a TRS-80 Color Computer (which I still have in my garage), and then later I went to college for journalism and worked at a newspaper for a while, and the Model 100 was a must have for any professional reporter. These things were used regularly well into the 90s. We got to check out one of the shared M100s if we were covering an event which needed quick turnaround. I remember sitting in the bleachers of a college basketball game typing up a story feeling very cool.

I absolutely lusted after one to have for my own, but couldn't afford it when they were new. Then they became underpowered anachronisms and I just made do with fond memories.

About a decade after I became a developer/techie (my true calling), the Model 100 was one of those things that I decided I just had to own, so in the 2000s sometime, I found one one eBay and bought it. I've pulled it out a few times to play and it just gives me joy to own one. One of those life goals I got to check off.

I can't believe how little memory it has though! I wanted to use it to type up a blog post about it, and I ran out of space almost immediately! I think mine has 24k, and not all of it is available. It's insanely tiny. (See how long this comment is? I always write like this... A result of my original career.)

The article is pretty short, but actually has some cool info! So much stuff I never knew about the M100. The display system is crazy. The link to the manual is awesome - it never dawned on me to look. I may have to pull it out of it's box I'm the garage and mess with it.

The low memory was another impetus for upgrading it. I use a REX chip upgrade, which gives me a lot more storage, but the RAM can only hold an article's worth of words at a time, anything longer and you're having to save and load segments. (I'm the author of the original article, glad you liked the dive into the guts. There's so much incredible documentation and books about the Tandy available for free now!)

One other crazy detail I didn't have space to put in the article is that half of the driver chips are mounted upside down in cutouts in the circuit board! It's so the data bus and some other control signals can be daisy chained between them without needing another layer in the PCB.

I've got a Model 102 which is pretty much the same computer, only manufactured later. I mostly used it as a terminal for UHF amateur packet radio (9600bps FSK) back before there were any turnkey solutions for that.

Rumor has it that the Model 100 contained the very last Microsoft product in which Bill Gates wrote any code.

It's not a rumor!

> "Part of my nostalgia about this machine is this was the last machine where I wrote a very high percentage of the code in the product. I did all the design and debugging along with Jey." - billg in an interview with the National Museum of American History.

https://americanhistory.si.edu/comphist/gates.htm#tc35

Not to be all megalomanic.. but I wonder what will be the last machine I personally wrote code for. Code we write nowadays is mostly targeted at virtual machines, or even if it's low level at some idealised hardware (apparently based on the PDP-11?). Or maybe we'll go back to be coding for machine learning accelerators or whatever lies in the future that constrains us to specific optimised hardware.

You’ll end up like Firefly, where the trash collector was running Windows 98. Or was it ME?

The only issue with the 102 is that it uses surface mount components throughout, while in the 100 they are only in the display module, which makes 100's easier to repair, but YMMV.

Surface-mount components are *much* easier to repair than thru-hole components, as long as they aren't BGAs or TQFPs or other extremely high-density parts or parts with solder balls underneath. The 102 is so old it would likely only have 50-mil pitch chips, which are *far* easier to swap out than any DIP chip: all you do is blow some hot air on them and them come right off without any damage. DIP chips generally need to be destroyed to remove them without damage to the PCB.

It depends on the caps though - early surface mount ones can be terrible.

DIP is quite easy to desolder with a desoldering iron like this one https://www.ebay.com/p/2254498136 . You just have to avoid heating adjacent pin. For a DIP-8 like this:

I would desolder in that order 2, 5, 1, 6, 8, 3, 7, 4.

With an SOIC chip, I don't worry about "order": I just hold tweezers on the chip, blow some hot air, and it comes off in about 1 second. What you're describing is orders of magnitude more difficult and time-consuming.

Thank you for this thread, as it makes my fussing with soldering today to fix some shorts in a couple guitars (my own fault from poor soldering years ago) sound quite pedestrian so I should aim to do as best as possible, cuz y’all out here be doing advanced EE projects!!

Does this risk loosening up some of those chips' neighbors?

Yes, definitely, if they're really close together. But "loosening up" isn't a problem with SMT; as long as the legs are adhered to the pads with the proper amount of solder, it's correct. The risk is moving adjacent chips around so they're no longer properly centered on their footprints, so using the hot air gun does require some finesse: use enough heat and air velocity, combined with the distance of the tool to the board, to remove the chip you aim for, without affecting the adjacent chips.

I had one of those. I remember riding the bus from Ithaca to Manchester, NH through Vermont (back when the route went through Vermont) and coding up the Fast Fourier Transform in BASIC on it from first principles.

One of the best keyboards I've ever used. Unique feel, loved that thing.

That's why I was so motivated to keep it! (I'm the author of the article!)

Great work!

Personally my favorite keyboard is part of one of the greatest beasts of all time: the IBM Selectric III.

If you can find one (try CL locally, shipping isn’t wise) in above average condition under $300 I’d advise picking it up. Ribbons still available with a little hunting. Not sure about servicing availability, but mine is mint via the Son of the Lady who passed on, it was her prized possession…

Once you plug it in, turn it on, hear that hum, and get typing my goodness it’s a whole different experience. If you get a quick cadence going up around 60 wpm the aggressive attack of the ball strike starts to sound like belt fed machine gun bursts. It’s visceral, brutal, and when you see the text literally bashed and inked into the paper, it’s really cool.

10/10 highly recommend

Hi!

Can we see the upcycled machine at work? (Maybe there was already a link to more photos/videos and I just missed it?).

I posted a clip on Twitter in response to a similar query! https://twitter.com/stephencass/status/1572600095467618304

That was one of my first, as we sold the family house, that was in the attic and my family threw it away, still haven't forgiven them.

Buy a replacement! ;-)

I'd love to get something like the freewrite [0] case and put a full Linux computer inside. The cost is just a little prohibitive.

[0]https://getfreewrite.com/products/freewrite-smart-typewriter...

Yeah, and that's a huge case for such a tiny screen; I can't imagine writing for long stints is very comfortable on it. At the very least it should have a bigger screen, closer to A4 size like old fashioned typewriters.

But if you go for writing comfort, I would like to see something with more of a desktop screen form factor and a separate keyboard. But that's more for a desk.

Thanks for posting this link! I've written before about missing Model 100 or Psion 5 style computers. Simple devices designed for limited purposes with great battery life. The device you linked to looks like it follows in this Model 100 tradition and they also have a machine called the Traveler that looks like it follows in the Psion 5 tradition. Great stuff!

This is so neat - reminds me of my buddy over at www.RCRestoMods.com - site needs updating but that’s because he’s been busy working on things.

Lovely story and I hope young people start to see the enjoyment of up cycling. The auto world with EV conversions is really exciting. From Sweden to Italy to the US, all kinds of swaps are happening. I want to join the club with an 89 or so Ford Ranger and one of Fords new EV kits…

We could be on the cusp of a renaissance of repurposed things - with the environments concerns, just a change in attitude about disposable items may change again and not just for nostalgia.

I’m probably going to hurt my own wallet here, but if anybody is interested in sourcing some materials from a good cause, I have more than $1,000 spent here and have 100% satisfaction which is pretty amazing:

www.shopgoodwill.com

I used one of these in the mid-90s during a newspaper career. I'd go to the police station and transcribe stuff, then go back and re-type it line-by-line onto a Mac Quadra.

I'm sure there was a way to plug it in and not re-type, but I never got around to that.

> The M100’s LCD is really 10 separate displays, each controlled by its own HD44102 driver chip.

Wow, sounds like they were really pushing the envelope on what was possible with LCD driver chips in 1983...

One of my all-time favourite portable computing devices. Don't know how many words I tapped out on my over the years.

Not sure the keyboard is as good and got any history; but similar idea without the trouble:

https://www.clockworkpi.com/product-page/devterm-kit-cm4-ser...

It seems smaller:

https://www.youtube.com/watch?v=lyohFQGmIlU

The trouble is a big part of the point :)

One person's upcycling is another person's destroying an irreplaceable piece of our computing history. This is only slightly more respectful than the people who chop up micros to make "cyberdecks."

Started with a coco 2 (Tandy Color Computer 2). Brings back a lot of memories

EEVblog teardown:

https://www.youtube.com/watch?v=Prl6D7bqQo8

I really like the form factor of these. I need to remember to look out for one of them to hack on.

I guess remembering when those were on sale makes one really feel old.

I've got one to recycle.

Spent many hours with Model 100/102 cousin the Olivetti M-10

https://www.old-computers.com/museum/computer.asp?st=1&c=475

Hah, the description of the computer sounded a lot like the M10 that I have at home and that my uncle used in the 80s. I didn't bother looking it up yesterday, but thanks for confirming my suspicion!

If you’ll be getting rid of it I’d love to get it, if possible.

Trash-80!

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