 I have a new typewriter. This Bayhemoth, which only just fits onto my workbench under the camera, is a Canon Typestar 210 battery-powered thermal typewriter. You can probably tell by the way it says, Canon Typestar 210 on the top. I got this for 10 francs from my favorite shop which sells things other people have thrown away. I love these things. Not so much to use, but just the general aesthetic and the way they work. This one in particular, it's got this delicious, light, linear keyboard. I already have one, actually. One of these, an S70, which you notice is quite a bit smaller than the 210. This has, the keys are also linear, but they've got just a little touch of tactility to them at the bottom. I have converted this one to a USB keyboard, but I'm not going to do that to this one. So before we open it up, let me just give you a quick tour of it working because it is completely flawless. It runs off six volts and draws bad an amp, and annoyingly, the polarity on the plug is center negative, which I discovered too late, but luckily it didn't actually destroy the machine when I plugged it in the wrong way around. So it's very simple. We insert some paper, we type something, and it prints it, and I will wait for this to finish and I will remove this to give a better view of the works. So it has successfully printed, my typing isn't so great, in a rather nice high-resolution Courier 10-point font. The way it works is it's got a carbon transfer ribbon and a thermal print head, which is this little metal thing here. The head heats up and pulls carbon off the ribbon and sticks it onto the paper. You get to use the ribbon once. When you use it, it records permanently onto the ribbon everything you have typed before, so dispose of your ribbons carefully. I believe that this ribbon is very nearly brand new and there is a cunning compartment on the bottom where a second ribbon can be stored, which appears to be unused. So I was in luck there. I actually believe, judging from how clean this is and how little wear there is anywhere, that this thing has been barely used. I could open up the ribbon and see what people typed, but I won't be doing that on camera. Now, as you can tell, this is very much the German model with the quartz keyboard and all the accented modifier keys. Because it is a thermal dot matrix printer, it's got an enormous character set, including all the accented characters. You can see the huge numbers of symbols here, but we can also hit this button and I can't quite tell whether it works on camera, but if I lift it up like this, you can see on the little LCD display all the other characters you can pick. This is the character picker. Unfortunately, this thing has a very narrow angle of view and it doesn't appear to be adjustable unlike the S70. So either I can see it or you can see it. So let's get back to the typing. The way it normally works is that you type. You see the text you're typing here. When it reaches the end of the line, it flushes it out to the paper. I have actually been fiddling with this previously, which is why the margins are quite narrow, but let's just move the head over. I need margin release. So let's put that about here. Set the right margin. There should be a button to take me back to the beginning, but I'm not sure what it is. I think just pressing this will set the left margin. Yeah. Maybe it's this. Nope, that's microstep left. Well, just do it the long way. So let me just type a long sentence. Z and Y are swapped on German keyboards. There we go. As you can see, it is not the quickest printer in the world, but it does produce rather good results. You get a choice of two different fonts. So if I switch it to the other one, which is this, you get the famous script font, which anyone who's used one of these type stars will recognize. So let me type the same thing again. The beep you heard was a warning that I'm approaching the right-hand margin. This is a holdover from the old days of typewriters where there was an actual bell that rang when the carriage reached the end. So it has actually managed to fit all of that onto one line. Let me just wind up a bit to get a better look. Yes, that's a very interesting font. Anyway, going back to Courier 10, there's a wide variety of different effects you can have. This one where you can change the size if I hit four and then type something. So it is not quite as cool as the pen plotter typewriters that you could get, which would draw in multi-colors with a ballpoint pen moving it around in two dimensions, but it is still pretty cool. There's a whole bunch of other features, programmable tab stops, line spacing, justification in various different ways. In fact, I have it set to full justification, which I should probably change. Remember how I think this is this one? Yep. There are status indicators here that you won't be able to see that tell you what's currently set. This is the caps lock button complete with an LED. Interestingly, it doesn't toggle. Instead, you press Shift to turn it off again. All the commands are controlled by these two code and mode buttons, and there's a handy reference here to tell you what they all do. That's basically it. Oh, other features. Let's put this back to normal mode. Let's check that, yep. If I set it to instead of lined at a time mode to instant mode, whenever I press a key now, it will print it quite slowly. Luckily, there's a buffer. If I make a typo, I can press the delete key and then an interesting thing happens. If you notice that X has vanished from the paper more or less, what it's done is it's lifted up this blade here and has scraped the carbon off the paper back onto the ribbon. Unfortunately, you can't use it again. You can actually see here that the ribbon is not in terribly good nick because it's pretty old. Now, because it's a thermal printer, we can actually remove the paper completely, take the ribbon out and insert. I'm trying to drop it. My role of 1980s era thermal paper. Now, I'm trying to remember what side of it has actually got the thermal coating. Let's try it this way around. Let's just feed it. This paper is coated with a material which, when it gets hot, goes black and then fades slowly to brown over time. Let's put the carriage back at the beginning and type something. Oh, good. That was, in fact, the right side of the paper. That works absolutely fine with no ribbon in it. You can still get thermal paper today. This stuff is about 40 years old. The only problem with it is that these days it's only really used in things like cash register tills. So buying less than about a kilometer of thermal paper is quite hard. But if I ever run out of these cartridges, I can at least fall back to that stuff. It does go brown slowly over time and tends to be a bit curly. But one of the really interesting things about this is what's inside. So let me just unplug it all and take the lid off. I've already removed the screws. And I'll show you. So it is fastened together with plastic clips which, as you may have gathered, I am not really a fan of. But once you open it up, you get this nice little single-sided board which miraculously is actually labeled. So we have here the ROM which is socketed. It is even marked as 2 megabit ROM. Over here is the memory for it which is 64 kilobits of SRAM or 8K. Sadly, that's not very much. And I spent ages looking for the CPU. I originally thought it was this thing on the other side of the board. But it actually turns out to be this enormous chip which is a CPU architecture I have never even heard of before. This is a TMPC 90, the 9841. It is a Toshiba Z80 retread. It's not a Z80 clone. It uses a very similar instruction set. But they changed it in a lot of ways. They've added a whole lot of new addressing modes. 16-bit operations and other cool features. And have rearranged the binary encoding completely. So I believe it is source compatible with Z80 code but will not run pre-assembled Z80 code. Now the fact that this is a processor that is fairly well known and the OS is on ROM means that with luck I should be able to remove the ROM replace it with an existing EEPROM that I have and run my own code on this machine. I'm still not quite sure what this would be useful for but it would be cool. So one thing I want to do, which I will do now if I can find a screwdriver is I just want to take a look at the other side of the board. These boxes here represent chips on the other side. So I looked this one up. It's a gate array. It will contain a whole lot of custom logic. I don't know what it's for. I don't know how to read these things or how to understand them even if you could. It could be to do with the LCD. By the way, I'll show you the bottom of the keyboard. There's the metal backplate for the keyboard. This is the LCD module, which has a completely standard LCD controller chip. So this will be a parallel port which will send commands to the LCD controller chip. And that will then display stuff on the screen. I got the LCD controller working on this thing so I expect it to be very similar logic. This has, I think, an 8-character display. It's a standard HD-Wattsit character cell display. Now, it feels like it's... Oh, there's a screw here. The printer mechanism is run by two stepper motors, one of which is in here and the other of which is... You can just see it peeking out there. Both of which are pretty large and meaty. The printhead itself, because it's thermal, actually uses quite a lot of power. This thing consumes an amp when it's printing at 6 volts. I don't know how long the 5D cells would last, but I suspect not terribly long. Oh, there's a clip there. So what have we got on the bottom? Not a lot. This is... This is the gate array. These two glue chips, they're connected to the... This is the printer interface. Could be stepper motor controllers. They seem quite small for that kind of power transistor, but they're connected here, so they're clearly something to do with the printhead. And this is the CPU. One of the things I'm interested in is that some of these pins are actually a UART. And I will actually just go and look up which ones. So the UART, there's two of them, is pins 59 to 56 of this gigantic 64 pin chip. So 64, 63, 62, 61, 60, 59, 58, 57, 56. These four here. Now what are they connected to anything? 64, 63, 62, 61, 60, 59, 58, 57, 56. I see that these two, which are the receive pins, are tied together. These, that's tied to that. Now the pins up here are things like CTS and RTS. I'll have to go look up what they are. Interesting. This is one of the transmit lines. That's tied to this linkage that then connects to something over here. There are some solder pads, but they don't actually seem to be much on the other side. These connect to these two. There's another linkage over here, and that's why it's down. Okay, so it's obviously using one of the transmit lines to control the printer. I wonder if these two chips here are the entire printer interface. And the CPU prints things by just sending commands to these. I'll have to go and look up those chips. That would be nice because it means that I can print stuff without needing to control all the stepper motors manually in software, which is what I originally thought it was going to do. Anyway, the next thing I want to do with this is to remove that EEPROM and attempt to read it. Oh yeah, the other UART, I think it's not used. It looks like the pins are tied to ground or at least something else. So I might be able to isolate those and use them for debug IO. The instruction set itself looks really rather interesting. It's got lots of useful addressing modes for doing things with 16-bit values. Like you can actually do proper 16-bit arithmetic now. It's got ADD SUB and all the ALU operations work 16-bit wide on the HL register. It's got direct page support for accessing built-in RAM up at the top of memory. It's got a stack relative addressing mode. It's got all kinds of useful things for writing compilers with. You can actually transfer 16-bit registers in a single instruction now. So I might do some impromptu tooling for that and then see if I can make my CalGold compiler generate code for this thing. And I will try and put some on an EEPROM and see what happens. But yes, the first thing I want to do now is to remove this ROM chip, stick it in my ROM reader and dump it. I don't have any way to lever this side because all this plastic's in the way. Okay, let's take the board out again. The processor supports 16-bits of address bus for reading code programs, but 20-bits of address bus for reading data. The IX and IY registers have been expanded to be 20-bits wide. So this 2-megabit ROM will contain 64K of code that will be probably mapped down the bottom plus huge amounts of data which are probably the font tables used for printing. Now it would be nice if there was more RAM. 8K is not a lot for running a real operating system. I might be able to get CPM on it if I was willing to reassemble CPM to the new instruction set. Of course, I wouldn't be able to run any CPM software, so kind of not very useful. But I'm sure there are going to be interesting things to do with it, even just to play with the instruction set, which sounds really quite interesting. And one thing I could do with it is, if that second UART is unused, stick a socket on the back and turn it into a printer. There we go. One ROM. So now I get to put the board back on for real. The board itself, as you can see, is single-sided and looks pretty easy to deal with. Oh yeah, I'm not going to put it on because I spotted this, which is the table telling you what all the configuration straps do. And these are these diodes. So all the diodes are in place except for B. And the configuration where B is open is the German model. So if I were to take one of those diodes off, and if I take this top diode off and put it in this position here, I should be able to reconfigure this as a UK model typewriter. So, I am actually going to give that a try now. Okay, so the soldering iron is hot. I've had a look at the board. It actually looks like there were originally four diodes and somebody just chopped off diode B, which actually makes a certain amount of sense. They make all the boards of all four diodes in place and then modify them later to avoid having multiple configurations. So I'm actually going to have to desolder the stub pins. Try and actually get this thing reasonably stable. That didn't work. I'm going to have to desolder the stub pins and the diode that I want to remove. And I might actually put in a new diode rather than try to solder in the old one. Okay, that's the wrong diode. Let me put that solder back again. This one I want to remove. Yeah, you can see the pin move when the solder melts. The other thing I could do is just stick a new diode in that hole. That would turn it into a US model. But let's try and make it British. Ah, the wire has in fact fallen out all the way through. It'll be in here somewhere. I will find that and remove it later. Okay, now I want to remove bottom one. So let's try and take the solder out. The state of the configuration straps will be read on start up when you turn the machine on. Okay, and then use to configure things like key maps and the language used for the messages. One annoying thing about the German keyboard layout is that you can't get all the UK symbols simultaneously. So you can't get an apostrophe and a question mark without reconfiguring the keyboard between each character. Now I do know that German users, apostrophes and question marks are not entirely certain what's going on there, but it's a pain when typing in English. The ends of the components have all been hooked over to make them stay in place while soldering them down, which makes them really awkward to unsolder. It has actually come undone. There we go. That's fallen off. It is there. Okay, so we have one diode. Let's just clean that up a little. And that needs to be put into whole B. Let me just double check that's the right way around. It is. And then we apply a little solder and we should be done. Now that pin needs a bit more. Okay. So we should now be ready to stick the ROM back in, reassemble this all and try and see if it works. However, I'm actually going to take a short break off camera to go and dump that ROM now that I've removed it because I don't want to plug it in and take it out too often. So let me just do the screws up and I shall go and do that. So, ROM dumping break. Okay, that took rather longer to dump than I originally thought. The label on the top, in fact, has no relation to what kind of ROM it is and eventually I had to guess. But I did get quite a lot of data. I think 256K out intact. It says it's a two megabit ROM. So two, one megabit half. Yeah, that makes sense for the size. So let's plug this back in. Yeah, eventually I just had to guess at a ROM model. I gave it the standard ROM pin out and it complained that the ID didn't match but it read. So good. So that is now plugged back in. We now need to reconnect the keyboard. I have this cable for the LCD. Actually, I'll do these ones first. These cables are for the keyboard. I think one of them is probe and the other is sense. This thing is very, very awkward. I don't like these connectors much either. They tend to go brittle and there. Or there's always a risk damaging the cable when you plug them in. Okay. I'm not going to reassemble it completely. I want to see what happens first. Plug in the power, turn on. Well, it still works, which is a good sign. Put the knobs back on. At least one of them. Okay, so the line mode. Line mode. Yep, that is now a Y key Z. Okay, numbers work. Yep, what about the shifted numbers? That's an asterisk. Okay, that's a very strange layout. And it now occurs to me that you won't be able to see what's on the LCD. So let's print that. So here we have the shifted numbers. An asterisk over one. I wonder what you get over here. Equals. Plus. Okay. Cube and two. Our underscore. Exclamation mark. Semi-colon, colon. Okay, that one makes sense. N sedilla and yeah, N sedilla. Quarter one eighth. Comma, good question mark. Dot twice. Half percent. That's deeply peculiar. Okay, let's put this into, set that to keyboard one and see if we get the same thing. Yeah, that looks the same. Let's try keyboard two. Yes, well, I have no idea what they were thinking of there. This is nothing like a standard layout of any description. This is actually set to English. Okay, that's an English message. It says title there, which is good. Let's try font. There's actually very few messages in here. That's bold. That's underline. Justification. Okay, top margin six. Yeah, this is now in English. Well, if I do manage to blow my own ROM, I could at least try and figure out where the key maps are and change them. But anyway, we have successfully changed the language of the machine, read the ROM. I know that works. So yeah, I think that's about all I can do today. The next step is to try and disassemble the ROM and see if it makes sense because, you know, I might have just read it incorrectly. I did go through it and there's quite a lot of strings, including, interestingly enough, a complete letter by Dr. Livingston in three different languages. I assume there's a test mode that you can enable somehow. Let's just try. Interesting. These obviously do something. Anyway, I'm going to call it there and put this thing back together and go and take a look at the ROM. I hope you enjoyed this rather scrappy video. Please let me know what you think in the comments.