Hi welcome to Tear down! Tuesday Got the MakerBot replicator here. A few people have asked to see what's under the hood of this puppy cuz it's not. do it yourself anymore. You don't build it yourself.

It's very consumer. it's still open source, so that means we'll have access or you'll have access to all the info available in this thing. So I thought I'd Flip it upside down and have a look under the hood. You know what we say here on the EV blog.

Don't turn it on. Take it apart. One of the good things is you can actually just flip it up on one end like this. and uh, not a problem at all.

And it gives you access to the electronics under the bottom panel here. And there's clearly this panel here. There's one screw on top with a square nut in there, which is, uh, the technique that they use to, uh, assemble the whole thing basically. But it's got this panel with uh, with um, hooks on here and here and here and here going in opposite directions.

So looks like if you take out that screw, this panel is just going to drop down a little bit and lift it and it should just lift out that way we should have access to the electronics. Uh, clearly the electronics is not mounted on this base plate cuz there's no screws here. But uh, let's take it off and see what's under there. And of course you could easily lose that nut.

Yep, I just did it. just dropped down on the floor. saw where it went. Here we go.

so you know it' be better if they had some other system in place. but TDA there it is. We've just got one board which does the whole lot which is a big uh difference to the if you see the Uh video for the makot uh thing Matic the Assembly of it. it had multiple boards all over the base place.

This has been replaced by just one with uh, five little daughter boards there which are probably the motor drivers. We'll have to have a look at that, but yeah, it's very close, clean and here we go. We finally found the fan in here that makes all that uh racket when the thing switched on and no wonder it does. It's only a tiny little pissant fan here, which uh, sucks the air in from I'll show you down here in a second but uh, sucks it from basically uh, inside the cabinet here, over the electronics and down and out the side here and out.

these bottom bits and there's the fan. What brand is that? I'm trying to read that upside down, a soning fonic or something like that. uh, it's a 24v uh fan little tiny pissant thing. really.

it's uh, hope those uh nuts, those Square nuts don't fall off there. they've used no locktite on that I don't think. Anyway, so what it's attempting to do here is suck air through uh, from the main cavity, up the top there through to the fan. But of course there's no um thing.

There's nothing here actually blocking this off. So if you wanted to do that properly, you would actually put something that blocks here and over there. so the fan. So the air is ducted from inside the cavity, there, through the fan and out.

Otherwise, you got, you know, recirculation, uh, stuff happening in here and clearly they've decided that they need, uh, some fan, uh, you know, a fan in here cuz they've got like, a, you know, motor controlers on here, which, uh, get warm of course and uh, Fair enough. Maybe they've done some measurements, some calculations how hot it was, got a fan, but yeah, they haven't implemented that right in two ways. One, there's no duct in there, and two, it takes the air from within the main cavity of course. and what have you got inside the main cavity? Well, you've got a massive heated build plate which is heating up tens or 100 Watts or something I don't know how much power goes into that and you've got the hot head and nozzle as well.

So Imag I'm glad it's actually got these cutouts on the side of the thing so you know you can get some, uh, relatively cool air. Imagine if this thing was sealed if you put some plastic over this or something to I don't know to make it look funky. it' actually get quite warm inside there and it' be sucking the hot air through the fan into here. so that's a I I don't know what? actually I don't think much thought went into that.

So really, there's an obvious way to do this correctly. and that's to do away with these standoffs here. completely. don't have that and get rid of your duck in problem at the same time.

Get rid of that. mount the fan directly onto the side of the case like this, and laser cut some you know, a big cut out in there with the fan on the side so it sucks the air in from the outside, the cool air, well, the ambient, uh, room temperature air into here and over there and you can do away with the standoffs. and uh, and you know you've got 100% ducked in from the outside. So yeah, I think they've got that, uh, a bit wrong.

I'm going to flip this sucker up the other way because uh, so we can ACC cuz this board has the text on up the other way so be careful not to grab the top. Of course, as I mentioned, you could, actually, uh, ruin the thing. well not ruin it. but uh, you could potentially Bend some of the Uh rods in there which hold the thing.

So there we go and we should be able to access the board and this, uh, silk screens the right way up. actually I was just thinking this. It's almost as if this little fan here was maybe an afterthought and they didn't want to cut holes in the side. or maybe they didn't want to cut holes inside for the looks I don't know so they thought they used the existing hole going up through the case.

but I don't know I don't like it. Now this main uh control board here is designed by Byy and we'll show you the Sil screen in a second. uh Jeremy Blum who's been on the Ow show? He's a fellow blogger so uh, check out his channel which is I think Sa Guy4 on YouTube and uh, he uh works for makeer board or did over the summer and he uh designed this board and he actually uh tweeted to me when I got this thing. uh please go easy on him.

um for the design. ah, you're not getting off easily Jeremy and there it is designed by Jeremy Plum based on the Arduino Mega platform and license is GPL version 3 and there's the Open Source Hardware symbol. Brilliant and uh, that's one of the things I complained about is that nobody put last time. uh, when I did the thing of mic nobody put their name on this thing but they certainly have this time.

Jeremy has and a whole other bunch of names up here and there's the design team I won't uh uh, you know, actually read them all out. but Bree's name is in there Charles PX who uh sent this uh makot to me and uh, a whole bunch of other names I don't recognize. but they're obviously uh, working at Make Aot and it's good to see that they've put some pride in this and they've put their name on there. In fact, they're the Dream Team There you go.

Now here's something interesting. On the side of the board. there's a Micro SD card slot. There's no cutout in the side of the case and uh, um, I'm not sure why they've uh, done that.

It's something called Club mate I have no idea what that is I'm sure it means something. uh, inside the make aot uh uh, Team or within the make aot Community perhaps and it's um, for refined pallets. There you go. I Love it.

So uh, clearly this is, um, put in there as a deliberate design decision. uh for you know, people in the know who maybe want to uh hack this thing or you know, customize it in some certain way. you can put a Micro SD solder in a Micro SD card there. you'd have to take out the board to uh, put in the uh thing anyway.

um to slide the card in, but clearly you could able to do that and maybe do some customy type stuff I like it. And the main controller here is an At Mega 1280 and as we uh saw on the silk screen, it's based on the At Mega platform cuz clearly uh you know they didn't want to uh use an Arduino Mega in here cuz that costs extra money. It's an extra board, an extra complexity, etc etc. You got to build Shields and uh it turn you know it's it's the it's the previous thing of maic.

So they decided to consolidate and that's the beautiful thing about open-source Hardware is that because all your a the design info is all out there, you can download it. You can customize it. But the main important thing about Open Source Hardware is that it doesn't use the non-commercial license and there's a lot of people out there that say oh why doesn't an Open Source Hardware you know allow you to use the non-commercial license if you want to use the logo here the Open Source Hardware logo why can't you have the right to have the non-commercial license? Well here is a classic case. Um, the Arduino uh guys designed the Arduino and Boards in the Arduino Mega in this case which this Design's based on.

but if makot wanted to do this which they they clearly have, they wanted to customize it for their own purposes and use it and sell it commercially. If it had that non-commercial clause in there, they wouldn't be able to do that. The community wouldn't grow, you know, and no one would be able to build upon other things they wouldn't want to CU they know they can't use it commercially, so that is why the Open Source Hardware Community do not allow and do not tolerate the having a non-commercial clause in a license. And they've got two six pin standard ICP in circuit serial Pro programming headers.

One here is as it says on the label. one's for the 1280 that's the main at Mega device and this one here is labeled 82 and that goes to the 82 uh device over here which handles the USB port just like on the new generation Arduino megas. And here we go. This is called the Mighty Board Rev E I Don't know if there's a more recent version.

we need to check it out. They've put in the web address make.com Do/ Mightyboard I Love Open Source Hardware There's the info. Woohoo! we can check it out. We can modify this thing, do whatever we want.

Brilliant! Houston We have a Bodge classic solder bodge between two pins on what looks like an opto coupler and there's another bodge. We've got a mod wire here and a classic uh, sliced Trace there. cut straight through and bridge between uh, these two power devices. One's an LM 1040 uh, low Dropout voltage regulator I'm familiar with that one and the other one.

can't quite see the number. but there you go. Bodgers couple of bodgers on the board never send a human to do a machine's job agent Smith We are living in The Matrix Folks and over here we have the HBP the heated build platform. that's those wires going off there? We've got an extra not sure what that is and uh, once again.

LEDs For all the fets up there, I'm uh, interested to see the circuit for that is that? uh, it just tells you if the fet is switched on uh, basically I assume that's uh, that's what it means there and uh. And then we've got a fan which drives the little puppy down in the corner. And here we've got some expansion headers for the Uart and the I Squar C bus and presumably uh, some spare IO from the Uh main at Mega Processor excellent and a couple of more status LEDs for that are unlabeled and there's a circuitry and the connector driving the wanky RGB lead strip B and it says 24 volts only with an exclamation mark So presumably it's designed to drive uh, large Uh numbers of series connected LEDs only and there's a thermo couple uh input for I've only got the single extruder, so uh, if you had the Dual extruder, you'd be using the second Channel Thermo couple there. And as for the axi limit switches here, they've got uh Z AIS minimum and the Y AIS minimum they're not sorry and the Zed maximum Uh ones.

They're there, they're designed in, but they don't utilize them and there's our five stepper motor boards. One of them's not uh utilized and we'll have to take these off and uh, see what's on there and no surprises. There's just a steeper motor driver which is in this case an Algro uh 4982 and a couple of uh support components. and that's uh All She Wrote And this is an intelligent device.

It's not just a grunty uh motor driver, it's a serial in. So it accepts uh serial commands or serial step commands from the main Arduino processor and it's designed to take the burden of that processor. So the processor just sends through a Serial uh pulse or a Serial command saying I just want you to advance one step on your steeper motor, please And uh, this chip handles all of the logistics of doing that and it's the make Aot bot. Step 177e is it Rev 17 I don't know, it's a REV e I'm not sure why they call it 17, but uh, there you go.

They've decided to put them on separate boards as opposed to the main board. Um, the design decision? Uh, for that would probably uh, be based on the fact that you know you want to separate. Um, it's not a bad design choice to separate your motor control from from your processing. Uh, board.

cuz then you can design your processor board real quick, get everyone up and working on the software, and then you can refine your motor stepper board. And if you want to change your Uh stepper Motors or anything like that, you can change the board in the future instead of having to change the main board. So that was probably the the design decision there to put it on a separate board and they may have even had somebody who uh, knows, uh, you know a thing or two about steeper. Ms to design this board and you can see the uh.

the chip obviously has a thermal pad under it. um cuz that's where the chip is and you've got uh, the nine VES there going from one side to the other. Classic thermal coupling and that would have had solder paste on the bottom of the Chip and A thermal pad on there to get all the heat out. and they use all the copper flood uh fill here which is uh yes, it is grounded.

There it is. You can see it thermally relieved to the ground pin there and that's used as a heat sink. My only issue with this would be the symmetry of the board. I.E You can put it in that way or you can put it in that way and presumably if you put it in upside down, well, something's going to release the Magic Smoke Woohoo! Hey, there's a little well, a big ass tanum under there as well.

And here's the data sheet for the a 4982 micro stepping driver from Aligro: Micro Systems INC and uh, it's I Highly recommend you. Uh, check it out if you're interested in uh, how these sorts of steeper motor driver controllers work. Very good bedtime. Reading these sorts of data sheets, features and benefits.

It's got low RDS yeah Automatic current delay uh, mixed and slow current delay Synchronous rectification for low power dissipation. brilliant Um in internal under voltage lockout as well. Crossover current protection uh works from 3, 3 and 5V compatible logic um available in Qfn and Tsop packages. Boo! Anyway, eh.

PA of the course, um, it's got building thermal shutdown short to ground protection short of load protection so you know doesn't blow up and what? I Love no smoke, no fire compliance I Love it. What that means is it tells you. Um, over here here it is. Uh, the ET package meets customer requirements for no smoke, no fire design by adding no connect pins between critical output sense and Supply pins.

So in case of a PIN to adjacent pin short, the device does not cause smoke or Fire doesn't let out the magic smoke I Love it. Um Additionally The device does not cause smoke or fire when any pin is shorted to ground or left open. So you know if you're using that leadfree soldering as most stuff the is these days. and you've and you've got some tin whiskers or something like that which grow, uh, look it up Google it if you don't know what it is.

uh, tin whiskers between two adjacent pads which is a little uh, short which can grow between two pads Bingo This thing's not going to blow up because if you have a look at the Uh package I'm sure we can go down and have a look at the pinouts usually right at the end. So if I jump down to the end here, uh, we should have the pinouts Here we go. and uh, it should have no connect pins between the various outputs. Here it is, uh yes, the ET package if you get the LT package here.

um, you don't get that uh Extra Protection but the ET package here. if we have a look at it, we can see that the Uh between all the critical pins out 1B and Vbb here they've got NC no connect. So there's that physical um spacing between those two pins and using the thing really easy. It's just got a very simple Uh interface here to microcontroller.

doesn't use that many Uh pins. It's got a sleep mode. you don't have to enable that if you don't want, but it's basically got a step control input. It's got a direction input you know, forwards or backwards.

It's got an enable and a reset and Ms1 and MS2 There there are just the Uh step selection pins. you could have those fixed or come from the microcontroller. that just tells you how far it's going to step with each pulse on the step input. Um, so very easy to drive with a microcontroller and it takes all the burden away from the software in the microcontroller.

It doesn't There don't doesn't have to be any phase lookup tables or anything, doesn't need to know or care about how to drive the step motor. All it needs is which all all the software needs to know is which direction you want to go and step bang. That's it. And the chip takes care of everything.

So that's the beautiful part about using an external Uh controller like this, which is a bit more intelligent than just your regular um, you know than just driving a H Bridge directly uh, from your microcontroller where you've got to take all that stuff for driving a particular step motor into account. So that's a really, um, nice design decision there. I Like it. And here's a simplified internal Uh diagram.

We've got a couple of decks here. We've got our serial input. it's got Regulators up here. it's got a charge pump for generating the required voltages, and uh, it's got a built-in um, built-in H bridge and uh, it gets that name from the shape of the circuit.

If you picture where my cursor is there going down like that. These two, these four, these two mosfets down this side, the two mosfets down here, and then the motor which is physically connected outside. but usually it's drawn with the motor in between there and it forms the letter H That's why it's called a H bridge and it's a very versatile and Powerful way to uh drive a motor like this. So it's got a dual H Bridge like that all the required control circuitry to drive it all.

some current sense resistors Rs1 and Rs2 here and uh Supply which is they've called Vbb And one of the things I love about these data sheets and why they make excellent reading is it's got typical layout information about how you lay out the boards. People ask, well how should I lay out a particular circuit Well, how do I learn it? well read data sheets like this and follow these example layouts and it tells you why various things are important. Look at this. It's got the thermal vires going with here, the thermal pad under there to get the heat out.

It'll probably have some calculations on that and uh, it shows you where you have to play the place the capacitors in this case. we've got some bulk capacitance here and interestingly, um, if you remember that, uh, the image of the the board we looked at it doesn't have any huge bulk capacitance on that board. On the plug-in motor control board, it was actually looks like the bulk capacitors is that uh, large tanum capacitor? that yellow one you saw like a D package? tanum on the main? uh on the main MakerBot board. it wasn't on this motor control board and I think that's a bit of a mistake.

It it certainly deserves Um and should be on this main board. Of course you will have a high frequency ceramic by pass cap there as well, which might be C6 or something like that down in there. but uh, you know those bolt capacitances can be further away from the particular Uh chip because they don't handle the high frequency Uh current spikes so the inductance the longer traces doesn't as matter as much. So you know they can get away with having it on the main board, but it's not good design practice it should.

The bul capacitance should have certainly been on this board. and in my previous video, a few people uh mentioned that they noticed that the LCD backlight or something happened to the LCD it's dimmed or something when I manually moved uh physically moved the Uh Motors on the you know on one of the axes and uh, they said that could be due to possibly they've left out the Uh reverse protection or the what's called a catch uh diode in Um in the Hibridge Motor Driver and in the data sheet here. Sure enough, it shows you all the Um pin configurations, what's inside each pin And here's the motor outputs down here of course. and um, and of course there are two diodes in here.

These two. here. there are two catch diodes there, but uh, they are the Uh, the parasitic as it actually mentions there. they're the parasitic diode which is inherent in the physical construction of the mosfet.

and I've done a tutorial video on this uh before so you can go look that one up and uh, um, often they are adequate. uh for the task, but uh, you've got to be very careful. Um, in in terms of uh, specking them to, you know to really know if they are suitable or not. You certainly may still need um, external catch ties.

and I'm not going go into a detailed analysis of uh, all the make Aot design and the motors and everything else to uh, tell you if they're if external ones were actually required, but they're clearly not using external Uh catch doets. I Don't see any on the board here I Haven't checked this, haven't checked the schematic yet, but there's physically none there. so they're obviously relying on the internal Uh diodes in parasitic ones inside the device. And you can see there's a couple of other Uh parasitic Uh ones here as well, and uh, other ones built into the various control pins.

And of course, there's lots of juicy info on uh, the motor Drive uh, waveforms here and the different Uh modes they can drive it in, so this makes really good reading. And there's the Uh step sequence uh table for the various Uh phases and how they step and whether you've got it in full step mode, half step, quarter step or you know, 116th step mode they're those two pins uh, that we saw Ms1 MS2 they would select um, these these four different Uh modes here. and uh, that is. you know all the stuff which, uh, all ordinarily your software might have had to take care of, but it's much easier to just design in a chip that's all handled for you.

Make no mistakes, spend your design effort somewhere else where it's needed. And if you have a look under the Steep Mot boards here, you can see these three vires here. They've left those uh, untended. so they've removed the solder mask.

you can see the other VES on the board. They're all tented of course, but these ones deliberately left it off and they've labeled them see y enable And then there's the Zed ones over here. step and Direction Um, they are presumably look like classic uh test Point Access so they might have a bed of nails uh, tester for this board to uh, individually, um, check the channel So they plug this board into a big uh test jig presumably um, or it might even be a debugging thing I Don't know if it's actually a production uh test thing, but uh, it could certainly be either. Um, and it allows you to probe the signals uh from either side of the board because the solder mask is left exposed there and I do like boards that have ground points there so you can Uh solder in a pin or a loop there.

So when you're uh, debugging this thing during development, um, you've got a very convenient ground access point for your oscilloscope. So overall, that's not a bad. uh, little board. It's a nice consolidation.

nice example of consolidating. uh, the existing thematic I'll have to compare the schematics you know to see how different it is to the thingo Matic but it's going to be very, uh, similar. how to combine all those, uh, different boards together? The thing Matic had like five or six boards in it into the one unit. and because it's Open Source Hardware they were able to do that and it's done quite neat.

So uh, Jeremy your reputation is intact there there. Um, you know there a few little issues, but that's nice. Uh, nice little layout I like it. and as far as the cable management in here goes, I mean it's not perfect, but it's uh, certainly, uh, more than adequate.

They've done a good uh job going up to the main uh extruder head of course I uh noted that on the uh review and unboxing there, but you know, generally considering that it's uh, uh, covered most of the time. There's a few Lucies around here, but uh, yeah, they've generally done a quite a good job. It's certainly a lot better than the thinger. Matic.