Hi welcome to the Eev blog an Electronics Engineering Video blog of interest to anyone involved in electronics design. I'm your host Dave Jones Hi It's product tear down time today. Yes, not product review cuz I I Didn't really think it was appropriate to review this particular product because quite frankly, it's 27 years old. Older than a lot of you kitties out there watching what is it? Well, it's the classic Tandy One 100 notebook computer.

Woohoo! Check it out! Isn't it Sex on a stick? really? this is the original 1983 Tandy 100 Uh, designed and built by Kyo Seer in Japan But uh, Tandy bought the rights to it and it was phenomenally successful as the Tandy 100 and later the Tandy 102. Um, and it was the last machine. It was the last computer that Bill Gates actually wrote a good lot of the code for, so this has got Bill's code in it. Believe it or not, there you go.

So I thought we'd take a look at it and uh, see how technology has changed or see what technology was like back then, the electronics and the design and build quality of the Tandy 100. Now I Thought this was a pretty appropriate product because it is essentially the world's first notebook SL laptop computer and it was phenomenally successful. They sold like over 6 million units of this thing. Unbelievable.

Had an unbelievably long life all the way through the 80s and even into the '90s as well. So what are the specs on this bad boy? I Hear you ask? Well, it's got an Intel 80 C85 processor. that's the seamos version of the classic Uh 8085. It's got 24 kiloby, a whopping 24 Koby of static rare memory.

That's that's kilobytes kitties. Okay, not megabytes or gigabytes. Okay, 24 kilobytes of memory. The processor runs at a scorching 2.4 mahz.

Can you believe it? Megahertz? Wooo! That's really screaming along. Um, it's got a 240 by Uh 64 mono LCD display that could display 40 characters by 8 lines. Um, it's got an Rs232 interface. It's got a printer interface.

It's got a a 300 board modem that's 300 bits per second. Okay, not Meg bits per second. That's bits per second. Kitties? Um, it's got a cassette.

Port Um, it. It could have external um floppy drives as well I think they um, uh, stored a who in like 160 kiloby or something like that. I'm not sure. It's got a barcode wand interface in.

It's got a fullsize quiry keyboard with excellent tactile feel and really, uh, it runs from 4 4 AA batteries in the back standard Aa's for 20 hours. Can you believe it? It got a 1 month standby on those batteries and it was instant on instant off. None of this booting up. Windows Rubbish.

Okay, instant on instant off. Fantastic. And really, it's no bigger or um, heavier than today's notebook computers. Fantastic! The one I've got here is got 24 KOB of ram.

It is expandable to 32 KOB but this one had a retail price when it launched to $1,400 That's $1 19983. So we do the conversion to today's dollars. But yeah, it was an amazing machine for its day. The world's first notebook computer.

And you know what we say here on the Eev blog? Don't turn it on, take it apart. We'll just do a quick overview of it here. And here's the power switch on the side here and you switch it on and it's instant on. Check it out and there it is.

It's um, it does have the Y2K bug. okay cuz it only stalls the year as two digits. but uh, there it is. Copyright Microsoft Here's the main menu.

You can go straight into the basic in here and there it is. Teros Trash 80 Model 100 Software Copyright They didn't want to put the use the whole word copyright cuz that uses a couple of more bites of memory you can't have that. can't just be pissing away a couple of couple of bites of memory like that. So Copyright 1983 Microsoft this one's 24 KOB So we got 21 uh, 1,161 BYT free.

And the uh, querty keyboard on it is is really just beautiful and it still works perfectly after 27 years. It's got function keys, it's got caps lock, it's got. you know? it's got everything kitties. It's even got cursor.

Keys Fantastic! It's got a memory power protect switch here so you can actually protect the memory. Um, you can back up the memory and switch it off. It uses four Aa's down here, just standard Aa's no problems at all. It's got an internal let's pop this open here.

It's got a Uh little expansion Port which has a couple of Um access for the Uh. For the extra ROM modules you can actually plug into it, which is rather neat. Um, it's got a built-in Uh, here it is. It's got a Rs232 port.

It's the biger old Db25 cuz they didn't have didn't use the Db9s in those days. They had the Uh 25 pin ones, the Um, the Centronics Uh printer port A Uh Modem Port standard A Uh It uses a Din socket and the cassette interface which Um goes to a cassette recorder for storing and loading. Really neat bit of unit. Um, now it's got Uh Direction and ACP for the modem um, answer and originate modes.

There they are. Um, this is this is the barcode, uh, wand interface. There it is. it's a D9 Um and on the side you've got Uh DC power input uh, the display, the display contrast.

There it is and the Onoff switch and that's it. Really nice functional unit. Okay, let's crack it open now to open it up. There's just uh, four screws here here here in here.

It's got these nice little rubber feet on the bottom so it sits on the desk nicely. There threaded machine, screw ones into brass inserts. very nice and then you just, uh, pop off. Uh, a couple of these little um Clips around the edge here.

so let's pop a few of those off and bingo Here we go here it is TA and that's the keyboard and LCD But here's what we want to see. Here's the guts of it. Check it out. Oh, isn't that retro porn for engineers? Oh, brings a tear to the eye.

It really does now. I'll show you the board. uh, closer up later. We'll go through it in detail, but as you can see, it's separated into two basic halves here via a standard1 in ribbon header.

Classic. Absolutely classic build and some standard Mlex connectors here. going over into Um, it looks like they're solded directly onto the Uh keypad board here. the keyboard circuitry.

There's the LCD. It's its own separate unit up here with quad flat packs, which we'll go into. and then you got the main processor board here, which is only a two layer job which is actually quite remarkable to actually get the layout on there and it's totally old school. It's totally late 70s early 80s build quality using off-the-shelf Parts I Love it! Okay, let's take a look at the main processor board.

Here's our classic 8085 Seos uh processor. Here's the Um the 6102 Uh Uart chip you remember back then you had to have a 40 pin dip chip just for the Uart classic and the Um 81 C55 Pio chip um which actually interfaced to the micro and allowed you to do the peripheral input and output and all that sort of functionality. Now here's your RAM modules down here into 8 kiloby uh chunks. Now this is actually quite remarkable because this uses like a hybrid technology which in its day was was actually was was pretty novel cuz normally you would um just put in one of these um dip um, one of these 28 pin dip style uh, seamos chips but they haven't They've actually gone for this hybrid module which converts the two so package chips into into the standard dip configuration and they've done that three times.

This one is 24 KOB of RAM and there's the optional 8 Koby which you can plug in and as you can see, there's your main Uh processor Crystal over there there's some. They've got some discreete uh, Point to-point wiring going from here over to here I'm not sure what that's actually for, but look, there's a little uh, bodgy resistor in there in some heat shrink. Check it out. there's actually it's it's been heat shrunk and put in there as some sort of I Well it's not an well, the the resistance looks like it's probably a mod but there's um, but those connectors are there for a reason and you'll notice everywhere on the board.

It uses standard 4,000 series Seos devices. you can still buy them today in the same packages doing the same job and they're just all over the shop. 4,000 series Seos. There's some Tl074 opamps up there which will go into, but uh, that 4,000 series.

Everywhere you look, you just they. They're just all over the place. Now down in this corner over here, check out the uh, real time clock. There's the 32 Kilz realtime clock.

uh Crystal and they've gunked it in there. They've They've actually put that, uh, that Gunk glue. that's not like, um, a battery residue or something like that. It looks pretty ugly, but that's uh, just oldfashioned, uh, gunking stuff that they've used to just, you know, pot, all the components to hold that Crystal in place.

And as you can see, they're all standard 4,000 series camos. But there's your uh timer chip. There it is. that's your Uh clock timer chip which is right next to the Uh Crystal But 4,000 series camos again, some standard um, Sip resistor networks and standard quar wat axial resistors for everything I Love it! And the bypass uh caps are all standard.

uh disc Ceramics they didn't have you know, surface mount Ceramics Back in those days you use the old dip um, the old radial disc uh type devices and you've got um, more 4,000 series Seos. There's your power supply over here. now. take a look at the power supply circuitry all around here and here's the schematic of it.

Look, check it out. How old school is that All discreet transistor solution? There's a Transformer there there. so they're using this as a switching regulator using discrete paths I Love it! There's a 4 A13 down there for the reset that's part of the uh reset uh circuitry and it's just quite. You know, really old school.

Now you would do that with one of those uh single chip DC to DC converter Solutions Of course, but you know, switching it. you know, a megahertz or something like that. Really efficient devices. but back then, that's how they did it.

Now if we hold the board up to the light here, as you can see, it's a double-sided just a standard double-sided layout. There's no inner power planes in there at all. It's all done as a double-sided layout. Brilliant.

My hat's off to uh, presumably the guy I Don't mean to be sexist, but uh, very few women were actually doing stuff like this back then, so it probably would have been a guy at Kia who laid out this board I'm sure he put a lot of Pride into it and just fantastic. I Love it! And all this circuitry around here is the modem and the cassette uh interface up here cuz the cassette interface has to handle the modulation and demodulation of the Uh serial tape signal which went to the cassette tape recorder and then the modem has to handle um, the isolation and um and the regular stuff that a 300 board modem did. Now as a comparison, here's one. 20 years l later this is from a notebook.

This is A this is a Um pretty much a top-of the range modern modem 20 years later. So as you can see all the isolation and it has to meet all much stricter requirements these days. There it is up close, much stricter requirements and uh, as you can see, it's come a long way in 20 years and this is only 300 bits per second. It's remarkable, but look at the amount of circuitry.

There's actually not that circuitry in there. It looks like it because there's lots of discreet resistors, uh dodes, uh, the Uh caps, and the opamps here and stuff like that. But really, Ultimately, there's not much circuitry in there at all to give you a complete 300 board modem and Um and serial cassette recording interface. Now I Thing to remember with boards like this: Uh, back in early 1980s, you could do four and more layer boards, but they were prohibitively expensive for a consumer item like this.

So it it would have been a major design requirement to fit all this circuitry onto a double-sided uh, a single double-sided board. Uh, single side load all axial components dip through hole component circuitry using offthe shelf Parts Cuz there's no custom devices on here at all. There's no custom As6 Not a thing, it's all using off-the-shelf Parts Effectively, anyone could have built this uh back in 1984 using all. these off-the-shelf components.

But of course, the uh computerated uh CAD technology wasn't wasn't really around back then or it was. but it wasn't really affordable for the individual to use, not even close like it is these days. And it's just remarkable how they've actually, um, built a mainstream consumer product like this, just using all standard off-the-shelf components of the time. You don't see that these days, very few modern consumer items will be made using just regular off-the-shelf components because it can't because you can't meet the form factor requirements, you can't meet the power requirements and all that sort of stuff.

It's you know, it's Unthinkable to do an iPhone or something like that using off-the-shelf components these days. And there we have the backup Uh battery for the Uh Seos memory. so you could actually remove the batteries. You could replace them and it would still retain all of your Uh contents.

No problems whatsoever. But as you can see, there's lots of even 27 years later, all these electrolytic capacitors none have leaked, none have bulged. Nothing like that. They're still all in remarkable condition because they actually made them properly back then, whereas now the Market's flooded with one hung low brand.

And you know, capacitors that fail. Everyone's familiar with failing capacitors in consumer products these days, but this still works perfectly 27 years later, and I'm sure it'll still be probably be working in another 20 or 30 years as well. You'll probably be able to switch it well. I Don't know, maybe not.

You might have to replace a few caps after after 60 odd years, but still, it's in remarkable condition and it still works a treat I Love it! And the other thing to remember with boards and layouts like this: these double-sided boards spread all over the place. They've got. yeah, they've got ceramic bypass caps everywhere, but really, you know, layout wasn't critical back then. not even close because this thing only runs at 2.4 megahertz.

You could brutalize the layout back, then have it as big as you want, Big inductive tracers all over the place and it really wouldn't matter. a rat's ass, the thing would pretty much still work. It's Brute Force engine ing. Now here's something I find really interesting.

This is the LCD display board. Check out how many drivers they need for the 240x 64 LCD display. There are two things I find remarkable about this one is that it actually uses uh, quad flat pack technology which was fairly Advanced uh. back then it was fairly fairly novel.

And also, check it out. They've actually flipped this one. this. these ones up the top, this top row, upside down.

It's the same chip, but it's it's. actually. they've actually done a cut out in the board. They've actually routed out the board, it's been cut out, and they've flipped that chip up.

and they've flipped it on its back and solded it on the underside like that. It's brilliant. It's absolutely brilliant. why they've done that is because it makes the PCB layout uh, possible using a double-sided board.

So if they had to flip these top rower chips up the other way just like they do with these ones here, then they wouldn't have been able to fit this well. They would have had a lot harder time fitting this on a double-sided board with routing space and all that sort of stuff. And because they would have had to have a lot more uh vises up here and all sorts of things. So that was a really novel technique, a novel Uh layout, and Manufacturing technique to lower your cost.

One of the things I found really remarkable about this wasn't so much the computer itself, which is great, but was the documentation that came with it and the kind of documentation they did back in those days. I'll add a link to the Uh service manual for this thing. It has the complete theory of operation. It's got all the schematics, the bill of materials, the uh, the PCB layout, all sorts of stuff.

It's all in there and it was written by people who knew what the hell they were talking about, was written by the engineers who designed it most likely, and it's just remarkable documentation. Check it out. So there you go I hope you enjoyed that trip down electronics and Manufacturing and computer memory laye there I Thought that was rather fascinating. just the construction, the double-sided boards, the all discreet circuitry they did back then, and just, uh, designing a real winin' product like this that that lasted for almost more than a decade in the consumer.

Market It's really remarkable. You hardly get that uh these days, but you know, over 6 million units sold and it was designed to meet a need. The world's first notebook computer. Look at it.

It's tiny really back considering the computers which were back in those days and it did its task and did it well. Sure, it's only got you know, 24 or 32 kiloby of memory, but hey, you know it's got a 20 hour battery life from a set of doublea's at lasts a month on standby. Really practical stuff that you're struggling to even get these days. Show me a notebook computer with 20 hours life these days.

And really, back then before the information revolution, you know all you wanted to do was type a document or something like that. It's not like you could play video games and surf the web, and well, you know this did the job and did it perfectly. And you can't type more than 32 kiloby of stuff in a day. Really.

so it was remarkably practical. I Love it. I Wish people just design things simplistically like this these days. Bloody! iPhones See you next time.