Laptops

Tandy TRS-80 Model 100 Teardown

Cracking Open the Tandy TRS-80 Model 100

Released in 1983, the Tandy TRS-80 Model 100 was one of the first truly portable computers. Before its release, mobile computers, such as the Osborne 1 are more "luggable" than portable.

We first cracked open the Tandy Model 100 back in 2008. And while our original gallery was good, I believed it could be better.

Since then, we've purchsed new photography equipment and honed our photo shooting and editing skills. And, I thought it was time to revisit the Tandy Model 100. Come along as we crack open the Tandy TRS-80 Model 100.

Photo by: Bill Detwiler
Caption by: Bill Detwiler

About

Bill Detwiler is Managing Editor of TechRepublic and Tech Pro Research and the host of Cracking Open, CNET and TechRepublic's popular online show. Prior to joining TechRepublic in 2000, Bill was an IT manager, database administrator, and desktop supp...

63 comments
Otto Roth
Otto Roth

I edited my post of yesterday and it has now disappeared - probably for scrutiny as I added a link to photo's of the Memory mod we made for the 100 in the 80's. Another thing I remembered of the Radio Shacks and never appreciated it till the IBM PC cam along was that the printer header was laid out as required for the centronics printer plug! So with a length of ribbon cable, an Centronics crimp on plug and a header plug, I could make up printer cables sometimes using a coke bottle as a hammer. When the IBM PC came out, it was a shock and frustration to make up printer cables - was a real nightmare!

rm
rm

My reporter friend owned one of these - we beefed it up to the max RAM, added an option chip that allowed the screen to display 12 lines of text (the display could display graphics, so the chip bitmapped smaller letters with no descenders (g, y, q, j were all moved up). A little harder to read but made it much easier to write paragraphs. There was a very similar machine sold by NEC that used much of the same hardware (beige case instead of white/black) and slightly different operating system software. My company replaced our old TI thermal printer terminals with the NEC for field service work. The battery life was WONDERFUL compared to later 286/386/486 laptops with rechargeable batteries. The only other laptop before 2000 that came close to this performance was the Psion MC400.

gswallow
gswallow

Started with a ZX81 kit while I was getting my degree. Then got the Color Computer. When I got my hands on a Model 100, I'd found an amazing little box. Added the DVI and a VM-1 and had portability in a full featured desktop of the time. Had to cross over to the PC world for my own economic sake. 8088 to P4 and then Mac. Sold my Model 100 setup to get a Zoomer which died and was replaced with a series of Palm and Treo devices. Sitting at my desk now and have a Dual G5 Power Mac, a CoreDuo iMac, and a Toshiba Portege M200 Tablet PC (added Bluetooth, 2.0GHz CPU, and 160GB hdd). Behind me are three P4 servers to be configured as my Web Server and MySQL cluster. In the midst of all of this I wished I'd never sold the M100 and so bought a Model 100 and 102 pair. Replaced the System ROM in both with the Y2K fix from Steve Adolf and upgraded them to 32k. DVI should arrive tomorrow which I will hook up to the composite in on a 32in TV. Now that will be a hoot. 80x24 on a 32 inch wide screen. No telling what the future may bring, but I won't let go of my M100 gain.

pejanssens
pejanssens

I still have a Model 100 with Multiplan in ROM. He never stopeed since the years 80 and some little programs and texts I wrote are still in memory. Since years he is plugged in and I change the batteries every few years... Incredible machine !!! I wonder how many years he will continue to work...

JanAlbert
JanAlbert

Great machine. Bought one as soon as it came out, back in '83. Much more useful on the road than the barely luggable HP85 or its successor in our office, the Compaq, if all you wanted to do was work on texts. Hook it up to a IBM Displaywriter or a PC with a null modem and you could transfer ASCII texts easily. Add a 300 baud telephone cradle modem and you could send texts back to the office from all over the world. Even after I'd switched to a Zenith ZFL 181 (8086, dual 720KB floppies, full-size keyboard), I kept using the Tandy because it was half the size and a third of the weight. Used it until I had a Toshiba that was about the same size. 1992, -93? Unfortunately, somewhere in the nineties, I couldn't bring it back to life and threw it in the recycling bin. Still making good use of the Zenith, though, with DOS 3.2 and MSWORD 5.0, though.

cosuna
cosuna

I don't know if you have noticed that this is a fringe item between true hole and SMT. Most of the mother board is true hole, but the RAM and all of the LCD is SMT. Reminded me to "The Wizard of Oz" which starts on Black-and-White and converts to Technicolor once Dorothy lands on the Land of Oz. I reason that most of the U.S. team was unfamiliar with SMT so they opted for a traditional des

tkeenan
tkeenan

At the time I was running continuing ed programs at the University of Calgary and wanted to include "a free computer with your computer course" (gimmicky but hey it worked...). I phoned Timex Canada at just the right time (when they were going out of the computer business!) and they essentially said "the computers guys are all gone, we're watch people" so I asked how many of these babies they had ("too many" was the reply.) I offered them $50CAD each and had them shipped to Calgary by rail! We also offered a kids version "build your own computer" class with the kits, but then they stopped making the kits, so I was in trouble! I was actually on a phone call to Portugal (the assembly location) where they said "crazy North American, we'll put them together with you" and I insisted they had to be in kit form which meant we got plastic baggie of parts with no instructions. We bought soldering irons, figured out the assembly and lots of young people got to "build their own computer." Those were the days!

Dr Dij
Dr Dij

I had the TRS-80 years ago and used it on many jobs. Unlike a foldup laptop, you could walk and type at the same time. This meant that you could do inside a business what people now: texting while crossing intersections against the light. We used this on our packaging line where, with an interface device that plugged into the memory slot on back, it sensed via photo-cell and triggered via output a thermal full sized label to spew and be rolled around a corner of boxes ready to goto the warehouse. I also used it on other jobs to take notes, etc. I finally sold it to a program many years later that used them to train disabled people to read or write or something. They liked the small form factor and went searching for these after they were long out of production.

mwarren
mwarren

The modem brings back memories. The cups fit over the handset. It was a great piece at the time and I could program a lot of useful things in their basic

jpenn
jpenn

Had to have it when I first saw it. Cost me a months salary at the time for the 32K version. I sold it many years later at a yard sale. I think I still have the cassette storage/player/recorder for the model 100 if anyone is interested!

simotaanisa
simotaanisa

any one who knows how i can get the learnig stff?

tashepa
tashepa

I bought mine in the late 80's at a church garage sale. I have held onto it ever since. I have several parts and pieces that go with it to. I was a bit surprised to see this article. Long live the Tandy!

Kc5oid
Kc5oid

You guy's, and gall's, should drop by www.club100.org sometime. Things are still hoping over there.

Doc Logic
Doc Logic

My Radio Shack digital multimeter had 9-pin serial, so I bought a thermister and linked it up to monitor and graph the house temperature. My Model 1 was also a great machine. Programming in 8K Memory taught me efficency!!! Remember 300 baud cassette storage?? 5-1/4 floppy was a miracle! And the great rectangular block graphics. All caps chip had to go.

JCitizen
JCitizen

the pictures are stunning, especially on my Montana real estate HDTV!! These articles really slake a thirst that I had when these things came out, but were too expensive to break down. I've never even been inside my IBM Convertible; but then it still works, so I'll leave it be until if fails.

laforsman
laforsman

Over 25 years of use! and it runs on 4 AA batteries.

pgit
pgit

Remember it came with two short plastic dowels with a rubber button on the end to prop it up.

FleetCommander
FleetCommander

I have a lot of fond memories about the Model 100... It was my first computer. My grandmother bought it for me as a Christmas present when I was in Junior High. I remember having fun doing "recreational programming" using some old BASIC manuals and porting old Apple BASIC games to it. When I was in High School, a couple of my friends and I were managers for several sports teams. I'd take our computer to the games with us and keep stats on it. We'd have the reports ready to go by practice the next day. There are many more things I fondly remember, but I won't go into them now. A couple of months ago, I pulled it out of storage and showed it to my three boys (ages 14, 11, and 8). My youngest looked at me and said "How did you get any work done with THAT?" and went back to play with the Wii, while my oldest thought it was neat and wanted to take it to school and show his science teacher "the fossil my Dad dug up." These kids don't know how easy they have it, do they?

gelfling6
gelfling6

I got mine way-way back when... It worked fine, til something fried the original 80C85 processor.. I managed to drop-in a 4Mhz 8085, which ran hotter than hell, and sucked batteries dry in mere minutes! A friend managed to find a source for the CMOS 80C85, and I replaced it back.. One other little note, I also found a small hack to speed-up the little bugger. (yes, Before Overclocking was chic, I was going it on the older stuff!) I found if you put a 6Mhz crystal in parallel with the 4Mhz crystal, it would run the 6Mhz processing speed, but at the expense of 2 things.. #1, battery consuption, #2, Cassette speed.. The Cassette I/O was clocked directly from the processor, so I managed to fit a switch with the 6Mhz crystal, above the 4Mhz.. If I needed to save to cassette, I just powered-down temporarily, slide the switch to disconnect the 6Mhz crystal, then power back up (yes, I left the case screws out, what about it?) Also used to use the Bar-Code reader port for non-standard digital Input.. A friend showed me a IBM-PC program, which would convert On/Off Morce code signals (using a tone detector) to ASCII text.. I wrote the program onto the Model-100, using the barcode data port as the detector. Ran great as high as 15WPM. I also found a 8080 machine code disassembler on an old CP/M BBS, added the 8085 instructions to it. I also manged to figure out how to force code out of a option ROM pack. Isolating one pin, made the option ROM look like a 2ndary memory.. I also made a short 8080/85 routine, pushed into the memory for the 'Prev' screen buffer memory, which would store up to 3 bytes of code from the Option ROM, then bounce back to BASIC to decode with the disassembler. Ah, my poor baby,PoCo.. rest in peace.. Keyboard is shot.. Haven't fired it up in years!

LedLincoln
LedLincoln

I had an Olivetti M10, which was essentially the same computer, but with a much nicer keyboard - I haven't felt a nicer one since - and a tilt-up display. Bought it from DAK.

mail
mail

I bought one of these in the UK in 1983 where it was sold as a Tandy machine and I loved it right from the start! Before this I had a Sinclair ZX81 then a Commodore VIC20 but these were nothing more than "play" machines - suddenly here was a really useful machine that really worked and delivered excellent functions. I learned to program on this and created the forerunners of programs that I still use to this day! Just seeing the machine in the photos raises all the excitement I felt so many years ago with the thrill of seeing it for the first time. I remember going to bed the night I bought it feeling a real thrill that I had something really special with which I could achieve almost anything! I used this machine pretty well exclusively until 1987 when I moved on to my first real desktop machine (which was an incredible step forward - it had a 20 MB (yes MB!) hard drive an 8 KHz clock speed - oh and it cost far more than the state of the art machine I currently use). Gradually I added extra assets to the Tandy - a real monitor and a disc drive unit. This was a very expensive accessory the size of a typical desktop PC box today whose sole purpose was to add a 184KB 5.25" floppy disk to the Tandy. Later I think I added a second drive too. I remember Tandy telling me I was moving up to a whole different level of computing with the disc drive - how things have changed! Later I also bought a Tandy Model 200, a fold up version of the M100 with a double sized screen much more like a laptop of today. Whilst it was fundamentally based on the M100 I never liked it as much and the supposedly larger memory was only accessible in chunks of (I think) 32KB so it was little more use than the Model 100. The only problem I had with the 100 in all those 4 years of intensive use was that the little function keys were not very robust and used to become unreliable, sometimes they worked, sometimes not, and sometimes they worked over and over again just on one press! I bought a pack of replacements and used to change them over from time to time. It was easy to dismantle and change discrete components with some careful soldering - just try anything like it today and watch the machine melt away! It is amazing how much power could be packed into that sized package today and even a tiny mobile phone will deliver much greater than the Tandy, but looking inside modern equipment is so disappointing - just a couple of black square packs and that's it. How lovely to see the superb layout and sheer quality of the Tandy that, as I remember, was really very reasonably priced. I really wish I had kept it for old times sake. What surprises me is that I look back with no fondness for any other machine I had before or since - they were just tools and when they were gone, they were gone, but the Tandy had real character and I still miss it.

Blawless1989
Blawless1989

lol nice to see somthing before my time that computer is older then i am by 6 years. it nice to see where we started with how computer where made with the big and cluncky chip set on the bored. i was suppridsed to see it run off of AA batterys that would be a frist to see that for a compurt of this type. but then again the probley did not need a lot of power unlike now with to days PC and laptops of over 60Watts

zingletorp
zingletorp

a magnetic tipped screwdriver in the middle of all of the chips!? (Sure - probably never use this "trash 80" again, but just "bad form".)

robo_dev
robo_dev

One of my first jobs was trying to sell these at a 'Tandy Computer Center' at the time before the tsunami that was the IBM PC and the compatibles washed the TRS computers far out to sea. Tandy had a go at the PC-compatible market early on (Tandy 1000/3000) and their ill-fated 80186 experiment, the Tandy 2000. Fast forward ten years, in the 1990s when doing PC support for a large corporation, I find that there was a senior exec who was given a PC, but had never switched it on. He had a Tandy Model-4 there on his credenza, and this guy was using VisiCalc to manage his personal investments (many millions of dollars), in VisiCalc. I told him that I knew all about it and we were instant friends, since nobody else in IT even knew how what OS was on that machine, much less how to fix it.

Dr. Solar
Dr. Solar

What a wonderful reminder of one of the best personal computers ever made! jjainschigg hit all the points of why this was a great machine. One thing that wasn't mentioned. The M100 only had one option ROM socket. The larger socket next to it and further from the edge (see images 13 and 49) is a "system bus" extension. Through that, you were able to add an expansion unit with two 5.25" floppies and an external, 80x25 character monitor.

jjainschigg
jjainschigg

Staring out over snowbound New York from my digital loftspace, past the array of quadcore-driven, fiber-fed widescreen monitors, my Android phone vibing at my hip, picture of post-millennial, post-ironic, totally-completely-post-Tandy Man -- yet my eyes mist over to see the old M100 once more. (sigh) It wasn't my first computer (I've been doing this since the Jacquard Loom, though the hair transplants and monkey-gland injections make it hard to tell except in bright sunlight). But it was a LOT of firsts, nonetheless. - The TRS-80 M100 was the first computer I ever rationalized buying as a personal productivity tool. Before it came on the scene, I had "computers I bought to automate offices" (various CP/M jobs, TRS-80 Model IIIs, minis, etc.) and "computers I bought to code games, do basic document-processing and fool around online" (Atari 800, later various Commodores, etc.) Buying a personal computer as an adjunct to _personal_ digital productivity (in something very close to the modern sense of the term) was very new. - It was the first "appliance" computer I ever worked with. The M100 OS and general ergonomics shares a huge amount of abstract conceptual DNA with today's smartphone OSs -- under normal circumstances, it never really shut down, always maintained application context, displayed all apps and docs on a toplevel 'home' screen, let you switch from app to app without losing cursor position, had a system-level clipboard, and moved gracefully in and out of terminal mode. - It was the first 'apps' computer I ever worked with. Folks forget that, for a couple years, there was a real third-party apps market for this thing (with cassette tapes and downloads as the distribution mechanisms). Some apps were coded in the machine's native assembler, but many were produced in M100 BASIC, which, for my money, was in many ways the most powerful and useful first-generation (i.e., pre VBasic) BASIC Tandy and Microsoft ever produced. M100 BASIC had all sorts of nice interoperability with low-level system features, smartkeys, etc., so you could make BASIC apps that worked like the native apps, and do cool tricks. - It was the first fully-portable, laptop-form-factor PC anyone had ever seen. The perfect journalist's tool -- suddenly, I could write a 1200-word story or live-transcribe an interview anywhere I happened to be, then file it by modem from any telephone. Plus, you got hours and hours of system life from four AA batteries -- more like a Kindle than my Droid phone. Totally game-changing. - It was, in many ways, the first computer optimized for social telecommunications. By the time the M100 came along, we were all past masters at BBSing, CompuServe, Delphi, MCIMail, etc. But portability, the built-in modem and direct RJ-11 connectivity (with acoustic coupler optional) took stuff like CompuServe CB Simulation to the next level. Also interesting to remember that the M100 was the last Microsoft project that Bill Gates himself actually wrote code for. Now that he's (even more) rich and (even more) famous and all, it's easy to forget that Gates was, at root, a coder. But he had a fine, workmanlike hand at 8-bit microcode, knew how to crank caffeine and play sport-death with macro assemblers at 3 AM, and had (and presumably still has) an acute vision for how systems should work and how they can be useful. The M100 is early testament to that art -- so many of its features have that sure-as-gravity "Well, of _course_ it should work that way" quality about them that characterizes really crisp engineering. How ironic, then, that Microsoft can't seem to win for losing in the smartphone market, when Bill essentially had 80% of the functionality idiom sewn up, 28 years ago.

techrepublic
techrepublic

I had to take a second look at the email when I saw this. Suddenly I was whisked back to 1980 and I had to laugh. I kept a trash 80 for many years to burn eproms and it served that purpose well into the PC era. But for the most part Commodore exceeded Tandy in so many ways IMHO. From Vic20, C64, SX64 and then Amiga, they all offered great graphics and audio. In retrospect, what most people today fail to understand is the amazing things these systems could do with very little memory and no hard drive! The C64 only worked on 38K of memory! Not MB, GB or TB, but KILOBYTES! Today, most programs are so bloated to operate in the MS world they need alot of memory. It was fun to see the old TRS80 here from a long time ago and a galaxy over at Tandy.

paxtrax
paxtrax

This was my first portable computer. I created some pretty elaborate proposals on that thing. It was a beautiful product on many levels. From battery life to the keyboard....Spend hours on planes flying around the southeast banging away on that device. And being an old Radio Shack guy (30 yrs ago) it brings warmth to my heart to see discrete components again. :-) The photo of the pico capacitor is classic.

pgit
pgit

This was mt first computer! I remember buying it the moment I laid eyes on it. After walking out of the store with my co-worker (we were corporate pilots) I started having buyer's remorse. Mainly, I spent the rest of the day lamenting "my wife is gonna kill me!" My partner thought it was pretty funny. But I got the last laugh. My wife trusted me to be responsible for my own decisions. If you think about it, that kind of "non" reaction makes more sense (evolutionarily?) than berating and brow-beating the spendthrift husband: If he has a good head on his shoulders he'll strive not to abuse that trust. If he's a deadbeat he'll abuse that trust swiftly, and you'll waste no time getting to the point of filing divorce papers. We've been married 30 years come this August. Anyway, funny how this thread shows up the day after I mention the model 100/101/102 in a thread here about quality keyboards. The 101 I had was the perfect keyboard for me. For a few years I tried to figure out how to use the 101 as the keyboard for the newer laptops I bought. ...I've always been primarily a laptop-type, I wonder why...? ;) I mentioned in that other thread that I eventually gave it to a friend who pressed it into service as a switch for a set of phones. As of about 6 years ago it was still clicking away. Not long after I gave it to him, this fellow showed me how easy (easy for him to say) it was to use it as an external keyboard. But without some sort of interpretation on the receiving end he said there would be a lot of weird characters resulting from a vast different in standards... whatever. This guy is the geek supreme. Runs the tech for a TV station. First Linux I ever saw running, he got me started on FOSS. Memories. Of all the computers I have owned I wish I still had that 101 more than any other. I have the second one after the 101 still, but it quit working around 2005. Model 2810HD IIRC. The "HD" was for "Hard Drive." The felt they should mention in the name that this computer had one. The 10 meant a whopping 10 MB on the "HD." That was an 80286 machine. I think I probably got the most production, serious work for the business, out of that unit. I wrote a formula for calculating what the cost of an airline ticket would be to any destination, whether an airline went there or not. This was based on the seat tax. I was able to reverse engineer what that cost would be, and compare it to the cost per passenger on our aircraft, on a flight by flight basis. At the end of the year I could sho each of the 4 companies involved what their airline costs would have been, and what they actually spent. 3 of the 4 saved a ton of real money by operating their own aircraft, and this was before hotels, lengthy car rentals and intangibles like employees having to be away from home often. The 4th didn't care. The plane was somewhat useful, more a luxury (impressed a lot of potential customers) and he could afford it. All with a 286. I justified my job with it! Through a couple pretty lean years. Talk about irony (and honesty) I used a subsequent P-II/win98 lappy to push the pencil, concluding we should disolve the flight department and put me on the street. The unfortunate consequence of government mandated major engine overhaul. Forget their actual condition, at XXX hours you rebuild, no arguments. I recommended this to the board, and they went with it. It bought me a little respect in this town...

jan80trs
jan80trs

... is not really a cry of hope, but a statement, a fact: these machines keep on working, keep on living, and keep on being practical for everyday use. Check out http://www.club100.org/

pgit
pgit

I'd forgotten about that! Thanks for the spark in the ol' memory. We had a weird grounding problem in our house, on occasion the voltage would drop dramatically on one half of the place and spike on the other. It would drop to around 90 volts. A friend helped me set up the 100 with the meter to isolate the circuit with the intermittent ground. Lotsa fun.

Bill Detwiler
Bill Detwiler moderator

Perhaps I can get hold of one and crack it open so you don't have to.

jan80trs
jan80trs

Repair it, or have it repaired. Use it again. Contact club100 on their website, they still support the TRS-80 Model 100 with hardware, software and advice. Join the mailing list! Relive the days when you were in control of your computer.

gelfling6
gelfling6

I can't remember the model #, but Kyocera also released their own version of the three. I seem to remember the M10 also had a few other features not included in the Model 100 & the Kyocera versions.. I vaguely remember the name of one of the lead techs of the project, Kioshi Kino , from the ROM. Also there was a couple of other names, which I found were used as hidden files for various set-up functions. (can't remember the name but one was actually the Prev screen memory file, while there was also a physical 80 X 15 (??) block of RAM, used. I took an old 8080 disassembler written in basic, added the 2 8085 specific functions, and also a small machine code snippet to poke into the previous screen memory block, that enabled reading the content of an option ROM (If you insulated the pin that told the computer an option ROM was inserted.). It sould call the machine code in RAM, to swap the internal to the option ROM, read a few bytes, save them ahead of the code, swap back to the internal ROM, then read them out.

pgit
pgit

Since you put it so well; quote I really wish I had kept it for old times sake. What surprises me is that I look back with no fondness for any other machine I had before or since - they were just tools and when they were gone, they were gone, but the Tandy had real character and I still miss it.

paxtrax
paxtrax

....If I remember correctly, I think the unit's Word Processor had a spell check also. Something I used all the time. ;-)

Bill Detwiler
Bill Detwiler moderator

I've never had a problem using magnetic screwdrivers to disassemble and reassemble gadgets and gizmos for TR. Years ago, I wouldn't go near a computer with a magnetic tool. But after more two decades of using magnetic screwdrivers and no problems (at least none that I know of), I've decided the threat is minimal. Now as JCitizen points out, I'm not saying magnetic tools can't cause problems, and I certainly wouldn't go rubbing them up against magnetic storage media. But I'll use them for removing a few screws now and then.

nwallette
nwallette

A hard disk, maybe. But not a semiconductor. If I'm wrong, The Internet will be quick to correct me, I'm sure.

jan80trs
jan80trs

The crop up regularly on e-bay below $100. There is still an active community supporting it with SD-card readers, replacement ROMs, task-switching hardware and a lot of good advice. Meet them on www.club100.org, an join the mailing list. Have fun computing again, knowing that YOU are in charge.

JCitizen
JCitizen

Ironically, I did the same thing with my first PC, which was a laptop too! After automating my office, I declared my self obsolete, and announced I'd be touring out because they didn't need me anymore. Seriously - I was bored - so I went to college. Should'a took computer science - but ended up a chalkboard engineer. Oh well! It was a hurdle I had to take. Congrats on your 30 year anniversary! :)

gelfling6
gelfling6

Actually, the Model 100 was based on the 8085, not x86.. (8086).. the 8085 was a variant of the Intel 8080, with 2 more instructions.

Doc Logic
Doc Logic

I still improvise electronic tools; some say it's old school, but I enjoy the challenge!!!

pgit
pgit

I thought spell check was pure magic, of course never having encountered it, or even imagined it before seeing it action. Formatting print jobs on the old dot matrix was a bit of a chore. I remember using one app that you inserted 'dot codes' into the text to indicate things like new paragraph, tab indent and so on. It was more work getting that right than any other part of 'word processing.'

gelfling6
gelfling6

Not very likely.. the Model 100/102, was probably the 1st laptop to run 100% memory.. the internal memory modules were CMOS Static ram, (capacitive charge gate) which continued to draw on a internal NiCAD battery, once the external power was turned off. They weren't affected by magnets, because the charge was the equivalent to charging a battery. But, all Static RAM lost it's marbles, if the power was lost. (unlike today's Flash-RAM, which itself runs on a limited life cycle before bit degradation.) The Model 100 wasn't RFI-Proof, though.. A few fellow amateur radio operators used to have a little fun, keying up 2-Meter handi-talkies with the antenna over the LCD, and watch the memory of the LCD screen go bonkers. So, maybe not solid magnetic, But definately 140-148Mhz RFI, did cause some problems.

JCitizen
JCitizen

are just that - semi-conductive. Any magnetic field can generate an unintentional EMF just like it does in motor windings or generators. This can have unintended consequences as well. Some circuits today have more shielding, but I was never allowed within 50 feet of even a control box let alone an IC circuit, with a magnetic screwdriver - especially not magnetic pickup handles - when I was doing that work. Circuit techs use high quality tools that will grip the screw head without many tricks, but if need be, the best brands had special screw holding tools. For example: http://www.service.kleintools.com/Tool/PRD/Category/Screw-Holding%20Screwdrivers%20SCREWDRIV-SCREW-HOLD Nobody beats Klien!

jan80trs
jan80trs

You mentioned a TRS-80 emulator, but for BASIC Level I for the TRS-80 model I Here is "Virtual T", the emulator for the TRS-80 model 100 (as in the article) + the Tandy 200 and Tandy 102 portable computers. Written by the Model 100 guru, Kenneth Pettit. http://sourceforge.net/projects/virtualt/

pgit
pgit

lose their jobs alike, eh? ;) I have no regrets about taking the lead on eliminating my own position, the most cake position you could have in any line of work. I was the total dictator and nobody, not even CEOs or directors, questioned my decisions. I had to earn that trust, but fate had it I did so dramatically in the first few weeks on the job. (long story) Thanks for the advanced congrats. All I can say is this woman I was lucky enough to come by is absolutely perfect. I consider myself the luckiest shlepp that ever walked the face of this earth. Ironically, I'm widely known as the unluckiest guy everybody knows, in absolutely every other facet of life. (my bad luck is astounding) The joke is every last bit of my lifetime quota of good luck was spent bringing me to the perfect partner and friend. I tell ya, if someone had offered me the decision to throw all my luck into this one deal all those years ago, I'd go for it in a heartbeat. I knew I'd never find anyone 'better' (for me) the instant I first laid eyes on her. Chalkboard engineer? Hasn't the chalkboard pretty much reached it's maximum design and manufacturing efficiency? =D Seriously tho, what do you engineer? Anything exciting?

pgit
pgit

I do recall that it was something spun off the 8080. Do you happen to know if the model 101 and 102 used the same processor? The 102 was the same as the 101 except 1/2 the thickness. I remember being so disappointed that they'd come out with the 102 so swiftly. I wonder why that hadn't considered the form factor in the first place... I have to guess they shoved the first ones out the door not knowing if it would fly or not. After it proved a hit they could justify investing in design and production.. maybe?

JCitizen
JCitizen

using SCOM to interpret raw printing data to my Zerox 460C typewriter. On my laptop you could see the global characters representing command code in the very documents I was processing. I was elated to find I could use Ctrl keys to insert these commands without modifying the document once it was loaded into the typewriter. I could work on the PC while my clerk banged away on the typewriter; it made for a very efficient office. I still have both machines, and I just have to rebuild the battery to get the PC going again! :)

paxtrax
paxtrax

Yea, I'd bring it back to the office and connect/transfer the documents to Word, then clean up the format there. The beauty for me was that after a day of meetings, on the plane home I was able to type up notes from the meeting, or create the deliverables while it was still fresh in my head. And back then you just didn't see people on the plane digitizing their work for the day...in a portable manner. It was my first digital productivity tool (besides my audiovox floor-mounted car phone), and I never looked back. Come to think of it, the car phone was analog. Smile.

JCitizen
JCitizen

I couldn't help revisiting this old discussion. Thanks for the rep Merch! Actually the old circuit designs were very resilient, but now days with circuit boards literally being printed, we strive to exceed the safety standard in this industry. Not so much because we want to preserve the circuitry, but because a brain-farting robot can kill personnel. So we just don't do it. If we caught a tech with a magnetic instrument, he got ejected from the building!

rmerchberger
rmerchberger

around any of the Model 100/102/200 systems -- I own & still use several... And if magnets were such an issue around this tech, why does the Tandy 200 use nice strong magnets to hold the clamshell closed? The only warning I've ever seen is "Keep floppy disks away from the magnets." ;-) "Merch"

gelfling6
gelfling6

Hmmm... I wonder how much it compares to the actual device? Downloaded a copy from the page, and about to review..

pgit
pgit

I have never been motivated by money or anything most consider "my own self interest." Curiosity has led me down my path, same as you. I haven't been fortunate enough to be able to take college level classes, let alone get a degree. But I can sure understand your motivation and celebrate your achievement. Way to go!

JCitizen
JCitizen

it is no longer chalk, but sweaky fiber tipped markers! HA! This is a saying in engineering, that we look at boring numbers and do nothing else of interest. I wasn't that type and started at the bottom of industry again, so that I could gain even more practical experience. I wasn't willing to move to better places of employment so I never looked for the really good jobs - I just wanted my degree for my back pocket. I ended up designing simple circuits in response to industrial needs of the moment. In one job I designed tools and built them for aircraft parts; in another I fashioned impromptu circuits for automated system. Most of the time, I just made things, or repaired robots. Whenever the staff found out I had a degree, they were shocked to see a floor mechanic with more qualifications than they had. I didn't mind, though, I only got it for my own satisfaction of "how-it's-made". I'm just too curious for my own good; and really don't usually push for anything that would be good or better for me. In my case curiosity keeps me sane, and happy, but little else! I'm so happy you found the right gal; I've never been married but for the same reason. I just can't commit to anyone that I can't see putting up with me for 100 years. If I live that long. B-)

gelfling6
gelfling6

The drive-side swap was kinda simplistic.. I masked off pin 32 (top-side, furthest from the notch between pins 4 & 6 (all odd pins on the bottom) and ran a wire from both drives, to this pin, with a 1-ohm pull-up to +5V,out to a mini jack through the case front, and the shield of the jack to the GND. Idea being, to change to the 2nd side of the drives, I simply used the command (forgotten, Yipes Old Age is setting in!) to toggle the cassette relay... Just had to remember in the program I was using, to remember which side I was writing to. I actually re-worked one of the basic Xmodem programs, to be able to write binary data in hex to separate files on all 4 sides, for huge binary files.. (used to drive an old RBBS-PC transfer program batty with the delays of writing the data.)

gswallow
gswallow

Am wondering if you'd be so kind as to shoot me an email with how to setup the double-sided disk swap? For that matter anything you might have about different drives in the DVI. Thanks in advance.

pgit
pgit

My memory was faulty. I had the 100, the 102 came out a couple years later and was basically the same only thinner. I still have the tape recorder for the 100, and a few other accessories. Still kicking myself hard for giving the computer away...

rmerchberger
rmerchberger

The 200 wasn't that odd -- the basics were compatible (except having 2x the screen real estate) - it was still based on the 2.4MHz 80c85, and all the ports were compatible. The 200 actually debuted the 40-pin molex buss connector, not the 102. My first laptop was a 200, and still my favorite, not only due to the bigger screen, but also because the arrow keys didn't suck, like they did on the 10x machines. ;-) Yes, the memory map was a bit different, mainly because the max. RAM the 200 could handle was 24K (per bank) instead of 32K -- but it could have 3 banks of 24K for a total of 72K. It also had MS Multiplan (spreadsheet) standard (which is why the ROM memory map is 40K minimum, limiting the RAM to 24K banks.) There are still people designing new hardware for the 100/102/200. Steve Adolph builds a couple of uber-memory upgrades called ReMem and Rex. The ReMem is a complete memory subsystem replacement (requires a lot of soldering) but gives access to 4Meg of Flash ROM and 2Meg of RAM! The Rex replaces the Option ROM and requires no soldering, but gives you 1 Meg of Flash, divided up into 16 banks of Option ROM and 16 banks of RAM bank images. Very handy little critter. Ken Pettit also built a device called a NADSbox, which emulates one of the old TPDD (Tandy Portable Disk Drive - would hold 100K) but saves the info on an SD card -- that SD card is still MSDOS compatible so you can easily transfer files to your PC. An excellent upgrade for those who participate in NanoWriMo, as the Tandy machines are still considered to have the best keyboard on a laptop... ever. ;-) The Tandy 600 was 80c88 based, came with 32K standard but was upgradeable to 288K RAM through two 128K chips -- It also had a built-in floppy drive (360K 3.5") and an 80x16 screen. Oddly enough, it's operating system was called HH/OS by Microsoft, which stands for HandHeld Operating System - and the 600 was nowhere near a handheld device... The 600 did have a built-in early version of Microsoft Word, Multiplan and I think a rudimentary database system, but it did *not* have a built-in Basic (and Tandy wanted $139 for the upgrade) so it wasn't very popular with the hardware hacker scene. At times, the 600 was barely compatible with itself, another reason it wasn't very popular. From what I understand, there were only about 75,000 units built, one of which is in my office; it needs a new battery pack. From the 600, Tandy moved into the 1100's which were "mostly PC" compatible, the BIOS's & Basics didn't quite match up, IIRC. I thought after the 1100's they had the 1400's, but by then I didn't care any more because it was all boring PC stuff, not kewl/exciting/hackable hardware. ;-) Laterz! "Merch"

gelfling6
gelfling6

Honest truth, I can't remember the 101, But I know the 102 had the same CPU.. I'm pretty sure the 102 was also based on the 80C85, because the 102 had a plain 40-pin molex connector off the back, for connecting the same external disk/video interface. (and connection was a 40-pin to 40-pin.) (Yipes! did I just date myself?) I bought one of the D/V interface units and had a functional BBS running on one.. (Using a pair of double-sided drives, and using the cassette switch wire to swap sides. Though, the interface unit DID have internal wiring for double sided disks. I never did figure how to work around that.) The Model 100, used a 40-pin DIP plug, into a ZIF socket, but the 1-20 & 21-40 pins were swapped.(1/40, 2/39, ....) I had to build a few replacements over the years.) Pretty sure they replaced the old Ceramic CMOS memory modules, with standard plastic CMOS DIPs, between the 100 to the 102.. The 200, was an odd duck in itself... Pretty sure that was 80C86 based. I think they finally scrapped it, and looked to the 1200, which was a full-fledged PC.