Hi, it's Vintage Computer time again. we love vintage computers here on the Eevblog and this time we have the classic RadioShack / Tandy Trs-80 or trash ad Color Computer or affectionately known as the Coco Now this one was originally released in 1980 and it was the follow-up to the original Trs-80 computer, but it is a completely different beast. This is the Trs-80 color Computer as opposed to the previous Trs-80 which was not a Color computer, hence why they had the fancy little red Korean and blue there. So it's actually a completely different design using a different processor.

but they kept the name Trs-80 even though the ad in the previous one pretty much stood for the fact that it used a Z80 processor. This one completely changed from Z80 to the Motorola 6809 processor and like entirely different but for some reason and they wanted to keep the brand in new marketing. and it's got a classic Chiclet style keyboard here. the chiclet 1 means it's got square keys with the spaces between them like that and the feel is very spongy.

You're really yeah, this is not your friend. This keyboard now the original 1980 model I started with the entry-level 4k model. It actually had a black surround on here, so this one must be a later unit than that, so ultimately was discontinued in 1983 or it was replaced by the Color Computer 2 and then the Color Computer 3 or Coco 2 or 3. But this is effectively the original design from 1980 up until 1983 and it eventually shipped with 64k of ram.

Now this was originally released at 399 U.s. dollars and that's 1980 U.s. dollars. and there was a pretty decent price Back in the day For a computer, you got to remember like we're computers like the Commodore 64 weren't around yet.

they'd be another couple of years or so. I mean not even the Vic-20 was around. Then the TI 99 for a wasn't around, then didn't come out until 1981. And so you know you had likes of the Atari 800 as a competitor the original Apple 2 ones like that.

So you've got to remember the market was still very primitive in 1980. Once we got onto 8283 with the Commodore 64 and other more advanced computers, then you know it got a bit more fancy. pantsy. But this was a state-of-the-art low-cost home computer in 1980.

So on the side here, it had the ah flap for the cartridges you could just plug in of course, your game cartridges and programme cartridges on the ROM and on the back. Nothing fancier. We've got a power switch left or right joystick. it was mains directly Iddyn under this hour.

IEC Rubbish. Dual joysticks affect me two players at once. Wow Fancy serial I/o port which could bugger off to like later on. they probably had a modem attachment or whatever and cassette drive.

Fantastic Channels select for the video and that looks like a composite output, but it's not. It's a direct RF modulated output directly to your TV so that's really rather annoying. But hey, they were designing it for the home computer so it couldn't go to a computer monitor. It had to go to an RF television and a reset button.

Don't accidentally press that, lose your entire program. and on the back here, just some vents there. And no, this thing didn't have a fan at all. And there's the label for those playing along at home.

Tandy Corporation. None of this. RadioShack Rubbish. This is actually an Australian version, hence the PAL format here.

220 240 volts Ac so different markets had to have a specular transformer. Why did them? It takes about 24 what so there abouts made in Korea Thank you very much. Bob's your uncle and serial number five. Oh three, Oh Four five.

is it for those playing along at home and this bad boy ran at a whopping 895 kilohertz or double that depending on how it was operating stuff like that, so not particularly quick. But hey, that was what it was back in 1980. And check it out. We have the operation manual for this thing.

Look at this. Let's have a look too customers. It's not very big so I can show you the whole blinkin lot. Really welcome to the Trs-80 Co.

Ah yeah, Ah, look at these. Oh strolling. The virtues of this bad boy. Really fantastic and installation connecting to your television set.

antenna. Hook it up! They've got all the fancy pantsy pictures just showing you what it is, how to hook up the cassette recorder, stuff like that, how to power it on the reset switch and it had nine colors Wow using the keyboard, using the joystick, using the cassette recorder to save and load programs and that was pretty much it. A couple of little demo programs or whatever, but that was that was it. Oh geez, so much of manual is it? But this is where it all happened.

Getting started with Color Basic fantastic and ah, look at all this look at all this, Ah, all these programs which they didn't actually tell you in there you had to like. go to the end to get the programs. They kind of like, you know, tried to make you do it yourself and all that sort of jazz, but you know a lot of work went into that and once you had perfected that, you went Extended Color Basic. Thank you very much for the larger memory ones.

I Believe Extended Color Basic was not available for the lesser memory model units back in the day. but huh? Look at the graphics, Look at the graphics are the pages are stuck together. Ah, somebody got so excited that the pages are stuck. No comment.

Alright, let's have a look inside this bad boy. as is very common with this design back in the day. haha. wear it like Flynn Lee This classic 1980 like early eighties construction Here you can't half tell with the ball all through hole construction.

The large ceramic cops down here for the bypass in on the memory and everything else. They just don't make them like that anymore really. and that's pretty hell you're doing. We've just got the cardboard over the top of the transformer here to insulate that we've got our power supply stuff up here.

It looks like it. We've got our main regulator, our RF modulator up the back. There's our process and we'll take a closer look if we got our roms there. We've got our memory and the PIO and the video display controller and whatnot.

There's not much in these things actually. The keyboard there we go. The keyboard just pops off so you can see the entire board populated there and just a double sided layout. Nothing fancy and it's just very typical of what you'd expect in a like late 70s early 80s vintage computer.

There's no custom Asics gate arrays or anything like that, just uses the off-the-shelf our Motorola stuff. plus just you know, generic 7400 series logic. You know the computer might have been made in South Korea but the keyboard made in Japan Oh, this stuff's made in Japan Now this definitely looks like a later model because look, we've got jumper switches here 16 K and 64 K if you can see that and over here as well. 16 K Like we've got the 64 K populated one.

Oh, just feel the power and sure enough, a Hm 68, 42 P D Rams And these are 64 K bit ones. So of course we've got 2, 4, 6, 8. None of that parody rubbish. Find it interesting that they got the thyroid beads in here.

They were taking a EMI into consideration the true magnetic interference I'll just trying to take the edge off all that nasty 5 volts TTL Running around on that double sided PCB Without the ground plane, there's the brains of the outfit the Motorola MC 6809 and this was a state-of-the-art processor back in the day. And above that, we have our roms I Don't know why we've got Rev 1.0 and Rev 1.1 I'm not sure what the deal is there I'm Bua Bua And above that is a curious beast. It's actually a 7, 4, LS, 7, 8, 3 aka a Motorola MC 6 w8 three and this is what's called a synchronous address multiplexer. If we move over from there, we have two other major large LSI chips.

So this one here is the MC 68 22 and this is the MC 68 21. And you probably can't have tell what the 68 22 is doing by the tracers going up here to the ribbon cable. it's going up to the keyboard and this one's actually what's called an industrial interface adapter. It's got like open drain outputs.

Another stuff for more industrial. In quote marks a type interface in whereas your Ass 68 21 is your regular RPI a a peripheral interface adapter. As a opposed to an industrial interface adapter. this one just allows you to interface with more generic logic as opposed to like having open drain outputs which are pretty useful for our keyboards and stuff like that.

And from there, if we head down, we've got ourselves the video control of the MC 68 47 P You can see the main crystal there they are four point, four, three, Double Three, Six, One Eight designates this one as a Pal unit as opposed to what NTSC which would likely have a different frequency crystal in there for the color subcarrier frequencies. So that's a dead giveaway that this is the video chip. you wouldn't even have to. you know? Look that one up.

You know just by the free code just by the crystal next to it. That's what it's doing. And right next to that there is our video generator. It's an RF video generator chip, but we're not actually modulating with the RF The RF is actually disabled in this chip.

They use a diode and whatnot to actually disable the RF our oscillator because they've got their own Aref our unit here. so this one is just working as a video mixer. Basically, that's the Motorola MC 1372. As you can see, it's basically Motorola.

Everything inside this I mean even the even year generic Jellybean 74 LS Logic seems to be Motorola so huge design when they just bought them in bulk. Yep, yep, Motorola as far as the eye can see. I Think the only thing that's not Motorola, of course is the memory up there. but geez there.

Oh no, no. NEC Roms Ah sorry. but I Believe on practically every other chip inside. this puppy is.

and the mains here is pretty how you're doing this. It's got this cardboard insulated flap, it's a key. you know it was par for the course back in the day. You know, you just don't find that sort of stuff these days.

And of course all your isolations done on there and then it comes off and you just got your regular linear regulators. Now, this switch-mode rubbish. and of course, your main five volt regulator up here. And this one actually doesn't switch the mains on the PCB The mains just go straight into the transformer so that's permanently hooked on.

and the power switch actually just switches the yeah secondary here. Now if we have a look at some of the date codes here: 14th Week 83 16-week 83 83 83 so it looks like guess what? we've got a 1983 vintage machine mid, you know, early to mid 83 vintage. So it's definitely one of the later units because this thing was almost discontinued by then. Now, if you have a look at the overall design here, it's basically are straight out of the Motorola application Note /r Datasheet: basic block diagram of a computer.

They just used the Motorola chipsets and they basically just slap the thing together. There was straight out of the application design was practically already done for them. The 6809 CPU was /m PU, the synchronous address multiplexer there, the Vdg, the video display generator, the Sixty-eight 47, and in the MC 1372 and they just whack on D ramp and that's it. The rest is just our the the Roma basically.

so it was just like an off-the-shelf design computer straight from Motorola So you know Tandy just went Me: thank you very much, we'll take that. So I Want to power this thing up and try it? but I don't have like a TV with an RFI input here in the lab anymore. So and that's the only output? we've got the RF output here. So I Thought that we'd build up a little circuit to try and tap off the composite video output because this thing's got to have composite video to feed into the RF tuner here in order to then modulate the RF and be received as a normal TV.

So it's certainly got the capability to do that. And sure enough, if you check online, there's various mods and things for adding a composite video output to the Coco here, but they don't seem to match up with what well the particular board I've got here. So the classic mod circuit says to tap off pin 12 of you 12 or for the new board or whatever that means I use 6 presumably still pin 12 of U6, but have a look at the chips so it obviously can't be you 12 there because that's just a 7 for LS sir, what is it? 273 and U6 is a seven for LSO - once again, both digital chips not that AHA that looks like it there. the MC 1372 that's you.

five on this particular board and there's the money shot inside the tuner for you to know fanboys I know you're out there. So if we actually have a look at pin 12 which is the are at which is normally the RF output of that 1372 look at that Bob's your uncle and then go up. there. you go.

We caught it. There is a classic. oh I Got some change in video information in there captured that That is your classic composite video signal. So this puppy is what it looks like.

It's working just fine. So that is pin 12 and also you can probably see there's just some. There's just a couple little budge boys over there going into the side of the RF tuner there and that also has the composite signal on there, but it looks like it's maybe slightly attenuated. Yeah, seems to be attenuated actually going into the tuner.

so I don't know what the difference is there. We should be able to tap off either of those though. I Suspect pin 12 of the chip. We're at 200 millivolts per division, so that's you know.

200, 400, 600, 800. That's like your traditional level for the composite video. Where is the one that's going to the modulator is? yeah? I don't think that's that great. So why it's attenuated like that? I'm not sure it's a requirement of the the tuner module there, but anyway, so let's try and tap off our pin 12 and see what happens now in theory: I don't think we actually need that transistor Darlington arrangement configuration to actually drive this.

We've got our coppers that signal because all that is is a common emitter follower that just drives the you know that dries the coax and doesn't affect the signal like it won't kill the RF output from here. You could use both at the same time for example, but I've just hacked in a cap in here because this does have a both of them have a very significant DC offset which you don't want. so I'm just a C couple in that into straight into the coax with nothing and into a little HDMI You know one of these little cheap eBay jobs and Tada? Look at that. We've got something.

It's not quite there, but you can see that it works. Extended Color basic copyright under license. Okay and hello. Well so it really doesn't like that at all.

and well. and I'm not sure whether or not it's because of the buffer or not I'd have to build up the Darlington transistor buffer and try it, but hey it, it's driving that coax and no problems. Well, at least we're getting something you know like I'm not sure whether or not this I haven't tried this decoder. it's just one of these eBay cheapies.

So I got no idea, but at least it's doing something. We can see that the computer still works Awesome! Check this out. If I actually reset the computer, Wait a second. There we go.

It almost came like it was perfect and then it just shifts off to the side so it could very well be something wrong with that little accomplice at the HDMI box and I powered it up and press to reset again. I was able to actually get a constant screen like this, but it's almost unreadable unfortunately. Okay, what I've hooked up now is a little jewel transistor to in double to double twos in a Darlington configuration. Just any meter follower got empowered from 5 volts over here tapping directly off the pin.

12 output video output of the 1327 there and through a 22 I'm Let's give it a go, shall we? Here we go? Gonna power it on and hello No oh it's gotta be that stupid HDMI converter thing. Alright I'm using one of these car rear vision display type things and there we go. That's not too shabby, but the colors are just horrible on this. They really are anyway.

we're back on the full monitor there I around with the maunder a bit and if I press that reset button I can actually get it to be stable as long as I You know, stand on one leg, hold my tongue at the right angle, and cross my fingers. Let's stick with that. That's alright. that's probably the best we're gonna yet.

So can anyone actually tell us? Did it really look this bad back in the day? Or is that just a modern you know issue with monitors and stuff like that cuz you know it's just horribly distorted? But yeah, I don't look at the flashing cursor. That's just horrible. Check it out. If we don't like that, we can change the background color I Don't know why it it comes up with still the green one at the top.

That's a bit ridiculous. What if we know if we hit reset it's just going to. yeah, it's just gonna go back to the green. but yeah, we can change it to any color we like.

Well, almost unbelievable. And of course it's all uppercase. but apparently obviously we can. press.

shift is zero to go into a lowercase mode and that's supposed to indicate uppercase and lowercase. The 1980s classic. What use is that really? All right? It's trying to see what this bad boy can do I put in a badass program? Look at this. We're gonna check out the color and the graphics capability of this thing.

Let's go all eight colors or whatever it's got I Look at the stunning graphics. Yes, that's the pixel resolution. That's as good as it gets. Ah, that was state of the art in 1980, wasn't it? Hmm.

and look at that paint drawing speed at the whopping what is it? 892 kilohertz clock rate. Fantastic. So there you have it. That's the Tandy slash Radio Shack Trs-80 Color Computer or affectionately known as the Cocoa.

And it was followed up by the Color Computer - and the Color Computer 3 before it was eventually discontinued. So the guy I hope you found that interesting. I'll link in about here at the end of the video. The original Trs-80 Color Computer one of the world's first home computers in 1977 I believe it was I've done a teardown and look at a work in version of one of those, so check it out so let us know if you had one of these things.

How long did you use it for? What model did you have? Did you upgrade to the Color Computer - The Cocoa? Three classic stuff. Those were the days. If you liked the video, please give it a big thumbs up because that always helps a lot. And as always, discuss down below catch you next time you.