Hi, everyone. I want to welcome you to today's lesson where we will be discussing the electrocardiogram otherwise known as the EKG or the ECG. By now, you know that I'm Leah, either lead in court instructor here at Advanced E-Clinical Training. So in today's lesson, some of the specific things that we will talk about is exactly what is the electrocardiogram? What is the ECG, the EKG? We will be talking about what is your role, specifically in electrocardiogram testing. We will discuss the electrocardiogram itself. We will also talk about how to perform an electrocardiogram. And then at the end of the lesson, we will go over some basic rhythms that you may see while you're in practice. And then also the rhythms that you, these will be the same rhythms that you will need to know for this certification exam. So I'm just going to go ahead here and get started. So what is the EKG? So an electrocardiogram abbreviated, as I said, is either an EKG or an ECG measures the electrical activity of the heartbeat. So with each beat of the heart, an electrical impulse or wave travels through the heart. And this electrical wave causes the heart muscle to squeeze and contract and pump blood from the heart. A normal heartbeat on the EKG will show the rate and rhythm of the contractions in both the upper and the lower chambers of the heart. So why would we, why would we be getting an electrocardiogram on a patient? Why would the provider want to order this? What is the EKG or the electrocardiogram going to show? So the indication for an electrocardiogram would be to determine or detect in a regular heart rhythm, otherwise known as arrhythmias. If a blocked or narrowed artery in the heart, otherwise known as coronary artery disease causes chest pain or a heart attack, the provider would want to get an EKG. Whether you have had a previous heart attack, definitely the provider would want to have an EKG as well. And also to know how well certain heart disease treatments, such as a pacemaker are working for that patient. And definitely an EKG will be ordered if any of the following signs and symptoms, whether it's chest pain, definitely the provider will be ordering an EKG. You can bet that 100% right off the bat. Dizziness, lightheadedness or confusion, heart palpitations, a rapid heartbeat or rapid pulse, shortness of breath or weakness, fatigue or decline in ability to exercise. Or if a patient is having a lot of shortness of breath that's newly onset while performing their activities of daily living. So specifically your role in performing the electrocardiogram would be preparing the patient for the procedure, providing the post procedure assistance to the patient. So that would be helping them to take off the electrodes, to put their shirt back on to help them sit up if needed. And also, of course, to accurately and efficiently perform the test itself also to help identify abnormalities that need immediate intervention. Now, please know that it is not your role to diagnose the patient or to read the electrocardiogram, but what you need to know, what you need to do is to definitely be able to identify certain rhythms that are abnormal that you would need to get the doctor or the provider in immediately. Also maintaining the equipment is super important that it's working properly and then also giving the provider the test results for immediate interpretation after the test is performed. So the EKG itself, the equipment consists of, of course, the EKG machine itself and it's made up of three distinct parts and this includes the electrodes, the lead wires and the main machine. There are 12 lead, the 12 lead ECG placement provides a whole representation by deriving and recording the heart's electrical activity through 12 different perspectives. Even though it is named a 12 lead EKG or ECG, it requires placement of only 10 electrodes on the patient's body. So I know that this sort of can be confusing and it was confusing for me when I first learned about EKGs and like why is it called a 12 lead ECG placement or 12 lead EKG, but there's only 10 electrodes that we connect to the patient's body. So just know that the 12 lead, all that is saying is that that 12 lead is going to show 12 different, I want to say pictures or 12 different perspectives of the heart beating through the heart muscle itself. But again, in this 12 lead ECG, there are only 10 electrodes placed on the patient. So performing the EKG in the implementation phase, of course, you want to place the patient in a sub pine or semi-fowlers position. You want to expose the chest, the ankles and the wrist because that is where the electrodes will be placed. You want to place the electrodes on the inner aspects of the wrists, on the medial aspect of the lower legs and on the chest. You also want to, after all electrodes are in place, connect the lead wires to the machine. You want to press the start button and input any required information, which would most likely be their first and last name, date of birth, the doctor ordering provider who's ordering the test exam itself. Those are mostly the required information that you would enter and make sure that all the leads are represented in the tracing. So if not, you want to determine which electrode has come loose or which electrode is not tracing appropriately, you want to reattach it and then restart the tracing. All recording and other nearby electrical equipment should be properly grounded, and we want to make sure that the electrodes are firmly attached. So this can get a little tricky, especially if patients have oily skin or if they have had lotion on or if they have been diuretic, if they've been sweating, if the patient is wet. Also, if the patient has a lot of hair on their chest or their arms or their legs, so you want to really make sure that the electrodes are firmly attached. So, you know, if it's not any emergent situation and you have the time, I would always like to take an alcohol pad and just kind of clean the skin where I was going to place the electrode that way. It kind of gets off the lotion or any sweat or any oil on the skin. And then if the patient is hairy, then you want to take a razor and just, you know, shade that just one small area where the electrode will be placed. So here is, we're going to talk in the next couple of slides about exactly the lead placement. So again, in this 12th lead EKG, there are only 10 electrodes that we will be placing. So I like to start first with the limb placement. So the white lead goes on to the right arm. The black lead goes on to the left arm. The red lead goes on to the left leg. And then the green lead goes on to the right leg. So the green lead and the red lead on this picture here. It's placed up a little bit higher, like it looks like on the groin or the hip area. Those leads actually need to come down a little bit further on the leg or on the ankle. A good way to remember how to do this is if you, a little rhyme or nomogram that I used to like to remember for this is, so the white lead is on the right shoulder. So it's, and then the green lead is on the right leg. So you want to remember snow over grass and then the left. So the snow over grass is the white over the green. So snow over grass. And then the black lead is on the left arm. The red lead is on the left leg and then smoke over fire. So that's a good way to remember where the limb leads are placed at least. So moving on. So of course, you know, we said this is a, even though it's a 12 lead, there are 10 electrodes that need to be placed on the previous slide. We talked about four of those. So there are six more that we need to talk about. So there's V1, V2, V3, V4 and V5. So as you can see here on this photo that there, V1 needs to be placed on the right sternal edge. So we know the sternum is the bone that goes in the center of our chest. So V1, you want to go to the right sternal edge, the fourth intercostal space. So what does that mean exactly? So it would be, you know, your collarbone and then there's rib number one, rib number two, rib number three, rib number four. So between rib number four and rib number five is V1, but it's placed on the right sternal edge. V2, you want to place on the fourth intercostal space in the same intercostal space, but on the left sternal edge. So as you can see here, it's on the opposite side as V2. Then V3 is midway between leads four, midway between V2 and V4. The fifth intercostal space or the mid collocular space, you want to place lead four. The left interior axillary line is where you want to place V5, and then the left mid axillary line, you want to place V6. Moving on to the electrocardiograph paper itself. So this paper is the paper that is going to be fed out from the EKG machine itself, and this is where the waves or the electrical impulses from the electrocardiogram will be graphed. And so I just wanted to make you aware of what this is exactly. So this paper can be displayed in a graph or dot matrix format with vertical and horizontal lines or dots at one millimeter interval. So the vertical axis, so we know vertical means up and down, represents gain or amplitude, and the horizontal axis displays time. So horizontal meaning this way. So each small vertical square represents 0.1 millivolts, and each horizontal square represents 0.04 seconds. I'm sorry about my typo there. So large squares are identified by darker lines and include five small boxes horizontally and vertically. So we can see here that this is a larger square with the darker borders, the darker and thicker borders, and then this is the small square. And you can see there are five squares that make up the horizontal axis of a larger box. So what are these waveforms and intervals and segments that we have been discussing? So each waveform, interval and segment has significant meaning on the EKG. The medical assistant is not expected to diagnose conditions, as I said before, but you must have an awareness of obvious normal versus abnormal tracings. So your role is to monitor the tracing as it's being recorded to ensure that the leaves were connected properly and that artifacts are not appearing. So what are artifacts? So different when we talk about artifacts, meaning that each waveform on the EKG paper should be straight across and should be easily seen. There should be no fluctuation, no scribbly lines, I should say. So let me move myself up here so you're able to see this just a little bit better. So here is the electrocardiogram. Here is the heartbeat. So this is the electrical heartbeats of the heart muscle, the electrical impulse. And so there are, we talked about PQRST and then here is the U wave. There's not always a U wave, but PQRST, PQRST. So the P wave represents atrial depolarization or contraction. So here is the P wave that we can see here. The QRS wave is, begins at the end of the P wave and the beginning of the T wave. So QRS and that represents the ventricular depolarization or contraction. We have the T wave. That's here. And that represents ventricular repolarization or relaxation. We have the U wave. And I, like I said before, that this is not always visible, but it represents the repolarization of the bundle of his and the purkinje fibers. So the PR interval, now we're talking about an interval. So the interval is the space between where the P wave ends and the Q wave starts. So the PR interval starts at the beginning of the P wave and ends at the beginning of the Q wave. So this represents, this interval represents the time it takes for the beginning of the atrial depolarization to the beginning of the ventricular repolarization. Next, we have the QC interval. And the QT interval starts at the beginning of the Q wave and ends at the beginning of the T wave. And this represents the time from the beginning of the ventricular depolarization to the end of ventricular repolarization. Last week, we have the ST segment. And the ST segment starts at the end of the S wave and ends at the beginning of the T wave. And this represents the time from the end of ventricular depolarization to the beginning of ventricular repolarization. So spend some time looking at this graph here to know what the P wave is, the Q or S wave, the T wave and the U wave. Those are the waves and their cells. And then the intervals, the PR interval, the QT interval and the ST segment. So here are some of the basic cardiac rhythms that you will need to know for the certification exam. But also for, I want you to familiarize yourself with so you know what a normal heart rhythm looks like versus what a abnormal heart rhythm looks like. Now again, it is not in your scope of practice to diagnose the patient or to even identify what these rhythms are specifically, but you need to know what looks normal and what is not normal. So here is a nice normal sinus rhythm. So this is what the EKG will look like for somebody who is healthy, who has a healthy heart, has a normal healthy heart rhythm with no arrhythmias. And we can see that it is, here's one heartbeat, two, three, four, five, six, seven. So this, you want to count the number of heart beats and times that by 10. So this, that will give you the patient's heart rate. So one, two, three, four, five, six, seven times 10 is 70. So we know this person's heart rate is 70. And we know that's a normal heart rate, right? Because a normal heart rate is between 60 and 100 for a normal person. So regular, like we said here, a regular rhythm at a rate of 60 to 100 beats per minute. Each QRS complex is preceded by a normal P wave. So what that means is here is the P wave that we saw. Here is the QRS complex. And then here's the T. So P, QR, ST. There's all the P waves are right before the QRS. Each normal P wave access. The P waves are upright in leads one and two. And the P wave, PR interval remains constant. So this P wave looks normal for each one of these heart beats. So here is sinus tachycardia. So this is an EKG rhythm for somebody who is tachycardic. And we know that tachycardic means that a person has a heart rate greater than 100 beats per minute. So how do we know that? Again, we count each one of these electrical heart beats. One, two, three, four, five, six, seven, eight, nine, 10. So we know this person is about 100 or more. So we're going to call this sinus tachycardia. But we can see that it's sinus, meaning that it's normal. There's a P wave for each QRS wave, even though this is a higher heart rate. Sinus bradycardia. So I know that you're all starting to probably see a pattern here. So the first rhythm we looked at was nice and normal. The second one we looked at was there were a lot of PQRS. There were a lot of electrical impulses because that person is tachycardic. Now this rhythm here is bradycardic. So this means that this patient has a heart rate less than 60 beats per minute. One, two, three times that by 10 is 30. But the rhythm is regular. There is regular meaning there is a P wave for each QRS and T wave, a P wave for each QRS and a T wave. That's how we know that the rhythm is regular. So what's a sinus arrest? So sinus arrest occurs when there's a sudden absence of electrical activity initiated by the SA notes. So this results in a pause in electrical activity seen on the tracing. Now, just because you see this, so you see the PQRS and then where is the PQRST? There's none here, right? So that means there's a absence of electrical activity. This doesn't mean necessarily that your patient is in cardiac arrest. It just means that they could go into cardiac arrest. This is definitely a warning sign here. And this is something you want to let the provider know about immediately. They could be in heart block, they could be about to cardiac arrest. So this is something that is very serious and that the provider should know about immediately. So again, here in these patterns of these rhythms that we're looking at, you're beginning to see what normal looks like, what a fast heart rate looks like, what a slow heart rate what looks like and what a heart rate looks like when it ceases to produce electrical activity. Now, just because you're looking at this cardiac rhythm or you're looking at this rhythm, and I said this doesn't necessarily mean that your cardiac, that your patient could be in cardiac arrest, but that's what they could very well be. So you're looking at this rhythm, but you're also looking at the patient. Don't ever, ever forget that. You always want to look at the patient and see like what is the patient doing? Are they breathing? Are they difficult to arouse? Are they uptended? Are they responding to your questions? So always look at the patient, but this is definitely something to be concerned about. Here's another one, atrial flutter. So what you can see here is this definitely looks different than normal sinus rhythm. It looks different than the sinus tachycardia or sinus radiocardia. So what this is is a narrow complex tachycardia. So this is basically when the atria of the heart is firing a bunch of electrical pulses at one time. At the ventric, from the right atrium to the left atrium. So instead of fall, instead of going boom, boom, boom, it's going boom, boom, boom, boom, but it's all over the place. There's no regular rhythm to it. So how do we know it looks like a flutter? So you can see this sawtooth pattern of the inverted flutter wave. So it just looks like this is fluttering here, right? These are fluttering P waves, but there's always a QRS, QRS, QRS. You have these fluttering P waves. So this is atrial flutter. This is also a rhythm that you need to be concerned about. A lot of people have atrial flutter. Sometimes they've had some patients say they don't even know that they can't even feel it. They have no symptoms. Other patients do. Some patients can feel a fluttering actually in their chest. They can feel heart palpitations. They could be short of breath. Other people don't feel anything at all. So it again is patient specific. So that's why you always have to look at your patients and say, you know, how are you feeling? You know, do you feel that? But this is a rhythm that is concerning. So you definitely want to let the provider know about immediately. Here is atrial fibrillation. So atrial fibrillation and atrial or a flutter are very, very similar. So again, this is an irregularly irregular rhythm. So this is coming from the atrium of the heart instead of the electrical activity being nice and with a normal rhythm like boom, boom, boom. It's all over the place. And again, your patients, some patients can feel this. They can feel the fluttering in their chest. They feel heart palpitations. They feel short of breath. They feel tired. Other patients, they don't feel it at all. They're in atrial fibrillation. So again, that's why it's always important to look at your patients. But when you're performing the actual electrocardiogram and you see a rhythm like this, I want to let the provider know immediately. The thing about a fib and atrial flutter is that these rhythms put their patient at risk for blood clots, at risk for stroke, at risk for PEs. And so this is something to be concerned about and let the provider know. But you can see in this atrial fibrillation, there's a QRS, QRS, QRS with these P waves are very irregular and there is not a QRS for each one of these P waves. So it's very similar to the atrial flutter that we talked about on the previous slide. It just looks not as pretty as I say for the A flutter. Asystole, this is a problem. A systole is a very, very big problem because it's referred to as a flat line or represents the cessation of electrical and mechanical activity of the heart. Your patient is in cardiac arrest. You need to call for help and start CPR immediately. This is a problem. Your patient is in cardiac arrest. Again, if this happens, look at your patient first. Make sure that what you're seeing is corresponding to what is happening with the patient, but this is a problem. They are not responding. They aren't full cardiac arrest. So you call for help. Don't ever leave the patient alone and you begin CPR. V-thib or ventricular fibrillation. Again, this heart rhythm is a big problem. It's chaotic. Your regular deflections. There's no identifying P-waves, QRS complexes or T-waves. There's a heart rate, but this person is in V-thib and they are going to cardiac arrest almost immediately unless they are defibrillated. But you as a CCMA won't ever defibrillate a patient, but if you see this rhythm and it's corresponding to your patient who's probably not responding at this point, you need to call for help immediately. And again, you need to start CPR, especially if they don't have a heart. If they have no pulse, you want to start CPR, chest compressions. If they have a pulse, you definitely want to just start with a rescue breathing with an ambu bag. But always call for help, but this is a big problem. Another one I wanted to just discuss here is premature ventricular contractions or PVCs. So you can see that there is a P-wave, a QRS, T, P-Q-R-S-T, P-Q-R-S-T, P-Q-R-S. And then what happened here? It's a P-Q-R-S-T, but it's premature because it's not following the same pattern as the other P-Q-R-S-T waves. It's premature. It's coming up quick. And so that's why we call those premature ventricular contractions or PVCs. So a lot of people have PVCs and they don't know that they have it. Again, some people don't have any symptoms or have indication that this is happening. Some people have occasional fluttering in their chest or heart palpitations, most likely. But this could lead to a dangerous heart rhythm, if not caught. But if you do see this while you're performing the EKG, this is not an emergent situation, but you definitely need to let the provider know. And that's the end of this presentation. I just wanted to make you aware that the rhythms that we looked at were only a handful of rhythms. There are many, many, many more. And if you plan to go on to become a physician's assistant or a nurse practitioner or a doctor, you or even a nurse, you will see more rhythms and get training on those rhythms. They're more complex. But for this stage of the game and for your role that you're currently training for, you only need to know the rhythms that we just discussed. And certainly you will need to know those for the certification exam. I thank you all for following along here with me. And please reach out to me if you have any questions or concerns. You know that you can do that at any time by email or you can schedule office hours with me. If you need any clarification, I'm happy to spend the time with you to provide that. So thank you once again and I will see you all again real soon.


I have a new typewriter. This is a Canon S70 type star 4, which I picked up at my local junk shop for the usual five francs. I got this for the keyboard module, which is lovely, but I want to see if it works. I know very little about this. I looked it up briefly online and I know that it's one of the line of portable typewriters known apparently as a thermal wedges, apparently due to the shape and the thermal printhead. I know it's battery powered and I know that the DC jack is centre negative, which is very useful to know, but other than that practically nothing. We can open the lid and see that here we have a printhead that doesn't move, which means the mechanism might be interesting. A film cartridge which has a little bit of ribbon left in it. Here is the actual printhead itself, which is the very characteristic thermal dot matrix printer, and that's about it. On the underside we see a battery compartment containing a rather interesting Nikad battery pack. The thing will run of D cells, but this is rechargeable. I have no idea if it's any good. Anyway, I want to fire it up and see what happens. So, yes, that DC jack centre negative is a little bit unusual, so if I can remember where I put my multimeter I might actually just check that, because I don't want to hook it up backwards and fry the thing. So negative is the coil spring here. Let's try the middle pin. Yep. Okay, good to know. Normally the label here will tell you whether it's centre negative or positive, but not this one. It does say six volts though, which is nice.  Okay, now I checked earlier that this is in fact the right size and this is wired up for centre positive, so I actually want to plug this in backwards, which is kind of unnerving. And plug in, return on. It did something. It's drawing about 10 milliamps. Interesting. Nothing appearing on the screen. Well, let's try feeding some paper. Oh, the screen has actually lit up slightly. It's very faint and I can only just see it. Okay, that's working. There's no repeat key on the backspace, which is interesting. Right. So, the way it works, obviously, is that I type and it goes into the buffer and then when I press the return key it should actually print. So, hmm, and it has printed. Rather badly. I need to set the margins. So, I do that, set the margins. I assume I move the cursor and then press the left and right margin buttons here. Yeah. Everything I do on this is actually going into the buffer. Now it has some facts. It's just going beep every time I press a button and there's nothing. There we go. Right. Yeah, I don't know how to work this thing. I assume that in order to actually set the margins I need to put this into direct typing mode, where when I press a key it prints out directly. Let's try the mode button. I can see something. That seems to be the line spacing thing. I don't think the camera is making out any of this. KB here sets the, whether you get the left or the right symbols in each of the keys. These will do the, these are controlled tabs. Code will let you do command sequences. So, this one is obviously orange. So, if I do code, I can just see it light up there in the center. Now I should be able to type and it's sent in some text. There's a little wheel down here by the power switch, which I believe changes the print density. So, if I wind this up a bit to one end, that comes out very gray. If I wind it around the other end, that comes out very black. Do I wonder how I'm supposed to change the margins? Oh, that's working now. Right. Space moves forwards and left arrow moves backwards. Right arrow apparently does nothing. So, left margin about here. Put the right margin about here. That should work better. Yes, that is working. Let's try some text. That beep means that I'm approaching the right hand margin. So, I need to print. Yeah, it's not really very nice to use. I assume I can just keep typing while I'm waiting for it to print. The return key is not particularly responsive, which is interesting. I wanted this for the keyboard module, which is beautiful. It's light and floaty. It's linear with just a little bit of tactility just at the bottom of the keystroke travel. And I'm going to take it apart in a moment so you can see how it all works. But maybe it just needs to go with some switch cleaner. Tab here does have print on it. So, let's just try doing code print. Mode changes a little thing down here, which I believe is the line spacing. Ah, no, I'm in settings mode. So, now I can write. I can do this to change the line spacing. This, I believe, is the font. So, if we try see. Yeah. Oh, I have it in direct mode. I wonder how that's happened. Okay, that is in fact the same font as before. So, that obviously was not the font setting. That is the direct mode setting, which is fine. That's just what I wanted. So, let's go back to mode setting. This one, yeah, this is going to be completely invisible on the camera. I can only just see it from where I'm sitting. This one is setting the typeface. So, that's underlined or fat. Here's not to actually work. Oh, I'm just not driving it correctly. Yeah. So, I think I can set it to this one and I've pressed mode again and it should set it. Yeah, fat text. There we go. And that's an even uglier font. Okay, let's put this back to normal. And apparently I can get underlined using this as well. So, set this. That hasn't not set. That's one, right. This box here contains the automatic line feed setting. So, if I just set this to auto, this is the font. It's giving me a choice of courier 10 or cubic. And cubic is one I noticed online. So, let's try cubic. Go back into type mode. The cubic font I saw online. It's interestingly rectangular. The paper's squint. The print quality is kind of terrible. I believe that as this is a thermal printhead, what it's doing is the the printhead heats up and transfers ink from the ribbon onto the paper. But the actual results are kind of grim. Did all this actually work with the lid open? Yes, it will. Yes, a typo there. If I was typing in buffered mode where each line gets buffered onto the screen here, you can then, of course, use the backspace key to edit it. Well, I'm not actually going to use this because frankly, I have a much nicer typewriter on the shelf over there which I use for envelopes and short letters and so on. And I'm also right on the verge of running out of ribbon. I can probably use thermal paper in this. I have some thermal paper for the Epson PX-8 printer. So, it would be interesting to try that. Yes, I'm going to go get thermal paper and see what happens. Okay, one reel of thermal paper. If you don't know what this stuff is, it's paper that's been coated in a special substance that, when it gets hot, goes black. You still see it today in typically in receipt printers for Tills. And you can, this paper dates back from the 1980s and it came with my Epson PX-8 printer. You can still get this size of paper made new today. But because it's for receipt printers, actually getting it in quantities less than about a kilometer is quite hard. And I don't really want that much. So, I've got four rolls of this, all vintage. I just hope that it's going to be enough. To last me, feeling it's a pain. This lever locks the paper against the roller. Let's see if I can just, yeah. So, set the margins. So, margin release should allow me to, yep, left margin goes. Here, right margin goes. Here, okay, try typing. Right, I put the margins in the wrong place. I was looking at the printhead rather than this larrow. So, let's do that again properly. After margin goes here, margin release first. Right, margin goes. Here, right. Now, let's try typing. Yep, that works fine. And it's still in automatic line wrap mode, but for some reason it hasn't automatically line wrapped. Yep, that works. The paper quality, the print quality is still kind of poor compared to the ribbon. It's basically the same. The paper is obviously yellow compared to the real paper, but it does work quite fine with thermal paper. Anyway, I'm not particularly interested in typing on this thing, as I said. So, let me just package up the paper before I drop the reel and spill it everywhere. And then I'm going to take the thing apart and see what makes it tick. Can't do any form of hardware without T. Okay, so let's power off and unplug and everything. And let's take the lid off. Actually, before I take the lid off, let's have a look at this keyboard. Because as I said, the keyboard is extremely nice. So, let's lift the key with my homemade keycap puller. I can get this in. There we go. Right, that's interesting. That looks like a key switch, like a proper key switch, rather than a rubber dome. And the keycaps are, they look like double shots with a mount. I don't know. I will, they're also filthy. I will actually go and look that up, I believe. Well, that's very interesting. Because hunting around online, I found one picture of a key switch that's obviously this on a PC keyboard, and nobody knew what it was. So possibly, these are quite rare. Well, if I'm going to reuse the keyboard module for something else, I kind of hope that it's an ordinary switch and not a capacitive job. Because they're a pain to interface with.  There are some obvious screws. So let's remove these. What I'm expecting to find inside this is the world's cheapest microcontroller board. Probably it's going to be a single system on chip. Given the age of this thing, possibly a Z80, possibly some other similar processor. One ROM containing the software and the font. And basically nothing else. No screws in there. They're screws down these holes. They need a different screwdriver. Those do not feel like screws. So it's probably clipped together. Or it's just some screws I haven't found. Ah, right. These things are the plastic inserts which these screw into. Does it need spudging? It does seem to be very firmly fastened together even though I've taken the screws out. Nothing there. The key switches on this are, so the keycaps rather, are actually quite shiny. I think this thing has seen a lot of use. They're fairly worn down. But because they're double shots, the white lettering is in fact white plastic embedded in the keycap itself. So you can wear them down right to the bottom and they will be fine. I have seen I have seen double shot keycaps worn so far down that the top is just completely white because it's worn through the gray plastic. But you have to have had a lot of use for that to happen. There's a crack in the plastic here. I suspect it may have been dropped. I'm not having any luck actually opening it. There's a screw underneath the spacebar. One thing that's interesting with this thing is that the labels are, well, this label is in German, Rechner Funktion, right. There is no screw under that spacebar. But the actual keyboard layout itself is mostly, is mostly US with the at sign here and the double quote here. It's missing some keys. So there should be three keys in a row here and two keys here, which might make this difficult to use as a PC keyboard, assuming I actually managed to get it out and make it work. So I'd have to do some kind of custom overlays. I've done this before on another keyboard and it's actually okay to type with. That feels like a latch. There's something in here. I don't think that's the way you do it. Oh, it is in fact just a latch. Okay. Yeah, they just clipped, it's just clipped together, but really well. So there's probably another latch here. Yeah. I believe that crack in the plastic might be new. So what have we got here? Keyboard module on a nice metal plate. These little keys here are now different key switch technology. Here we have the display unit. Yeah, there's a PCB underneath the keyboard. Oh, that doesn't lift off. Here we go. What have we got here? Motor for driving the printhead. Motor for turning the roller here. We've got control for the printhead, a 6301 processor, which is like par for the course. You don't get these anymore. They were a decent enough little 8-bit processor, cheap and easy to integrate. My PX8 laptop has got like two. This is almost certainly the ROM. This I've got no idea about. This is 64192 in an interesting package with the groove down it. I've got no idea about this one. Printer. This is the print wheel for the print quality switch, power supply, nicer fuse. Nothing of a particular interest. There's a big chunky power controller here that could be running the printhead. What have we got on this? The little LCD is probably a complete pain to drive. It is bespoke with the baked in symbols in the boxes below, but the top line is alphanumeric. If I were to reuse this as a PC keyboard, I could potentially make use of that, but figuring out the protocol would be exciting. I see on the back of the LCD board there's a surface mount job. Let's get this off and have a look. There's a push connector down these soldered things here. This should just unplug given a bit of assistance. This will be a LCD driver. What we've got here is where it connects to the main board. I can easily follow the tracks here. The board is single sided, which makes it very easy to work with, except the side with the tracks on it is in fact the side with the key switches attached, which is less easy to work with. One thing to note is that the caps lock key, or rather the control key, because that's what key goes here, has an LED on it. I notice that the key switches are not soldered through the board, and the key switches are in fact on the back of the board, which is very interesting. So I do wonder how the key switch has fastened down onto the board. They could be surface mount. Do I dare try to take the board off by undoing these screws? I suspect I don't. The screws are all screw locked down. Ah, it's SMK, they're a noted key switch manufacturer. So I could probably look that up. Yeah, in fact it does actually tell you the model number of the board here, which will be bespoke for Canon. Okay, I'm going to go away again and look up some of these. Can I unplug this? I can. Well, I can plug it back in again as a different matter. Okay, I'm going to go and look up some of these chips and see if there's anything interesting here. Okay, so I managed to identify this as being RAM. So this seems like 2K of RAM. Looking at the manual, you can actually store some text in it. I haven't been able to identify this one or this one. They're probably bespoke gate arrays, most likely for driving the print mechanism. The keyboard module itself I found a tear down for. They're not like proper mechanical key switches. They are integrated dome with slider with a conductive pad that presses down onto swirly pads on the PCB here. So it would be quite safe to take apart, although tensioning all the screws again would be a bit tricky. So this means it's probably not capacitive. So I might actually do a bit of experimentation with that. It seems to be obscure, but people know about it. I found a nice tear down of the keyboard module, which I shall link to below. So let's have a bit of a play. So I would need to, if I was going to reuse this, I would need to somehow, I would need to take it apart and map the tracks. I may be able to use the tear down I found to do this. This chip here, I don't know about at all. It could be a decade counter for scanning the keyboard matrix. You know, I forgot to go look that up. I'll go look that up. It's a NAND gate. I don't know why it's a NAND gate, but that's what it is. Okay, so let's do some continuity testing. So you have a terminal here that's labeled as plus. And I think this one, no, because I identified that one side of this switch here is this pad.  Great. This connects to grid. That doesn't need to do anything at all. I really hope it's not capacitive. The tear down I found said that it wasn't. So I was actually following the wrong track. So let's try that one again, because this button is connected to this pad here. So that should be connected to one of these. So if I press it, it should be connected to one of the others. Good. That means it's a simple switching keyboard, which is kind of what I expected. You know, I am actually going to take this PCB off. I may destroy it, but I want to clean the pads anyway. Wow, I can. These screws are. So in order to turn this into a PC keyboard, I need to use a microcontroller to scan the keyboard matrix. And I typically use these for this sort of thing. I've done this before with a different keyboard. This is a PSOC 5 development kit. It costs about $10. It's a reasonably high grade arm with lots of IO pins, which is what makes them good for this kind of project. And, you know, usual stuff like built-in debugger. But one really cool feature is there's a built-in FPGA type thing, which is programmable. So you can actually program your own quote hardware, unquote, which makes them really easy to do cool stuff with. And it speaks USB. So I can just wire it directly up to the keyboard matrix and probe the pins. It looks like this particular board has rather more pins than I was kind of expecting. The last keyboard I modified like this actually had its own built-in counter for one row of the keyboard matrix. So I didn't have to drive both sides of the keyboard matrix from the microcontroller. Instead, one row simply controls the counter. So not a counter, a decoder. That is, you give it four pins in a binary number and it selects one of many output pins based on which one you select, because that reduces the pin count hugely. There we go. Here are the the bottom. Yeah, you can see the rubber dome with a little conductive pad. Wow, they're really clicky. Let's just unclip. Is this going to unclip? Here's a key switch. So if I remove the key itself, hopefully without breaking it, I can see inside that there's a it actually has a tactile clicky mechanism in addition to the rubber dome. That explains why it feels so nice, because normally these rubber dome keyboards rely on the rubber dome itself to do the tactility. Now which way up did it go? And while I have this open, I'm just going to wipe over these contacts with alcohol. So let me go get some tissue, because that will just clean up the contact somewhat. I could also do the conductive rubber pads, but I don't think I want to in case I manage to clean the conductive layer off. It's not working as well as I thought. The solder joints are actually getting in the way. This will just make things a little bit nicer. Okay. Wow, I've forgotten how much this stuff smells. Yeah, if I start acting weird, that's probably not the fault of the alcohol. So what's this NAND gate for? So one interesting thing about the keyboard is the repeat key down here. Now I kind of assumed that this was being handled by software, but I wonder if it's not. It goes this way up, because the repeat key here, this pad connects to this pin of the NAND gate. I bet that what this is is built-in repeat mechanism in the keyboard. So if you hold the repeat key down, an oscillator causes any other key you have held down to pulse, thus giving you a repeat mechanism. That's actually a little bit of a problem when it comes to a PC keyboard, because I do not want this to happen for a PC keyboard. It's always possible to simply remove the repeat mechanism. Okay, but anyway, let's have a look at the bottom of this. Now this key has got some goop on it. I don't think that really means anything. You can see that these keys have a clicking mechanism, while the little ones don't. Okay, while I'm going to reassemble this, I will just point out that the light on the caps lock key is here, and there's a little hole in the PCB here for the light to stick up, which is cool. Actually, before I assemble this, let's just trace these lines. So that is the outer track. It goes to here. It goes to here. Okay, my musing's about the repeat key. I've got the board turned round. This is the NAND gate. These are just an Inca pads. So there's jumpers. So in fact, it's not connected directly to the NAND gate at all. Yeah. If I was going to actually do this, I would need to thoroughly trace the PCB and all the connections. It's a maze. But we need to figure out what was connected to what. Okay. In fact, once again, I am forgetting that I've got one I need. And these screws are Phillips, so I need the Phillips head. I think they're Phillips. It doesn't actually... Yeah. They're not very good Phillips. Phillips and positive drive are different, and you need to use the right head or your damaged stuff. But positive drive is actually an improvement over Phillips for torque reasons I don't know the details of. I have these screwdriver set not to apply too much torque. So one of the advantages of the PSock microcontroller is that I can just wire it up to all the pins on this connector, including the ones that get routed through to the LCD. So I can drive the LCD too. One thing that's very interesting is the LCD controller is a noticeably different generation of technology from the rest of the thing. So the keyboard is a crude single-sided PCB made out of this orange laminated cardboardy stuff. Okay. The computer itself is... It's a more traditional green fiberglass PCB, but it's all through-hole 0.1 inch stuff. Well this thing is a double-sided surface mount device. HD447AT. I believe that may be standard. Yes it is standard. It's the ubiquitous serial connected alphanumeric display controller. So yes this would be trivial to control. Nearly all this circuitry is just wiring it up to the LCD itself. But here this connector has only got a handful of lines. They're rather more than I was expecting because you can drive a 44780 from like three lines. It just needs an I2C or SPI. So I do wonder how that's configured. Okay. So let us try and reassemble this and see if it still works. One thing I very much need to do is to remove all the keycaps and wash them thoroughly. The tops are kind of shiny from wear, but I can also see stuff embedded on the side of the keycaps. They're really quite nasty. And let's fire it up again and see if it works. See if it still works even. Okay. Power on. Nothing. However, I have forgotten to reattach this and it may actually be important. Tiny little screws. Now let's try it. Power on. Six volts. There we go. And in fact, this is now working substantially better. So remember the mode I was in. So I don't know if the camera can see it now, but if we go here to L mode, L mode, switch back out to typing, see, there's text. So that still works. This is a one, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15. Dean character display. And it's also got some extra segments. We've got tab, decimal, tab, indent, center, one, one and a half, two, the line spacing, C and L for line mode and current mode, X, X, X, X underscore, X underscore, X and X underscore for the font size, carriage return, auto carriage return and oh, it does justify A and B, I don't know. And oh, A and B is the font, which allows you to choose between cubic and courier. I know that's what they are, because if you go over here, it actually tells you the name courier cubic. And I and I is for the keyboard setting. I believe that's all the features. It may be rather lacks on keys. Unfortunately, I need to make probably either one of these or this escape because escape use a lot. This would become meta or out. I might make this meta and this one out code down here could be the the layer modifier for cursor keys. With the other keyboard, you can't see me press mode because there's too much stuff on my desk. There's code down here. My other keyboard, the cursor keys were the layer key plus WASD, Q and E were home and end, R and F are page up, page down, etc. The tricky bit is over here. So we have we need some more keys from somewhere. So like I program, so I need access to square brackets and curly braces. And normally these go in these two keys. I wonder if the could the backspace key be movable? And no, it's centered. See, I was hoping it would be offset to the left a bit because then I could move one of these keycaps here down here and put the backspace key up here. But no, that's not going to work. I mean, I could still do it, but then there would be this unsightly gap. Another thing I'm not particularly key on is the very small right shift key because that's the one I mostly use. And the enter key is misplaced. The enter key should be, well, for an ISO keyboard, it should be here. So this, I mean, the key feel is really nice. I like this a lot. I'd love to have this as a daily driver keyboard, but I might need some extra keys. Let's hook the stabilizer back in. Hook this. Now that's interesting. So the stabilizer hooks under these things here, but there's a curved piece. And I believe that's for attaching the stabilizer. So it didn't work. I wonder if that's supposed to trap the pop up maybe. Yeah, that hasn't worked. So I thought those curved things were actually to make it easy to fit the keys.  But I think I was wrong about that. So you can see the one on the left is hooked on and the one on the right is hooked on. There you go. Okay. Now, thinking about this in terms of retrofitting it, we've got here one, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 17, 18, 19, 30 pins. And my controller board here, I mean, it's easily got enough IO pins, but they're not actually arranged in a sensible fashion. So I would need some kind of adapter. So we've actually got one, two, three, four, five, six, seven, eight, nine, 10, 11, 18, 20. Call it about 40 to 50 pins. Some of the pins have dedicated meanings so that you're rather want to leave the debug pins which are up here alone. And some of the pins down here have capacitors attached to them, which is very poorly documented. You can remove them if they're these. But I kind of really don't want to. But I was going to build an adapter, then I wouldn't need to do that at all. So you've got two rows of point one inch pitch pins. The other thing is to find out what connector this is and get one. But I don't like this flex ribbon cable. It doesn't have a proper clamp at each end, which means that they are rather limited as to how often you can unplug them and plug them back on again. So I should rather not have, I shouldn't really have just done that then. Yeah. Okay. Let's stick the lid back on. There you go. Let's just, one final check to make sure it works. Tridge back in. I think for fun, I shall try and move this under the camera. Yeah. The hot zone mechanism where if you type close to the right hand margin, it goes beep. This lets you know that you're near the end of the margin and therefore you need to either manually insert a carriage return or the next time you press the spacebar, it will do it for you. The hot zone is actually quite small, which means if you're typing a long word such as apparently here, then it doesn't work, which is exciting. And there you go. There is my new typewriter. I hope you enjoyed this video. Let me know what you think in the comments.