Hi welcome to Tear down Tuesday I Was going to do something entirely different today, but at the last minute Something Turned Up for repair here in the lab and I thought well might as well do a tear down as well because I don't think we've had a Swiss or a tear down of something made in Switzerland before. So hi to all my Swiss viewers and I like to keep a breast of different Technologies So we've got a breast pump. It's a Medila Swing breast pump. Yes, cure the jokes but uh, it? I Don't expect it to be terribly exciting inside.

there'll be a motor with a micro controller to control it. Battery powered and that's about it. but uh I Thought we'd see what's inside this Swiss made breast pump and see if we can fix it. You know what we say on the EV blog? don't turn it on because we can't take it apart and here it is.

It's the Medila Swing and this brand medila is supposed to be the you know, the Ducks guts. This is supposed to be the fluke 87 of breast pumps I Guess you could, uh say that. sort of. You know the Deao industry standard.

It's got a tube here which attaches to the uh suction cup which goes you know where and uh. it's made, designed and made in Switzerland and it's got four uh, soft buttons here on the top LED power um, up and down and I'm not sure what that one does. No idea. sorry I Don't go into the details how this thing works and it's a rather neat um, you know, a rather neat little shape and it actually contains the battery compartment here.

On the bottom, it's got a nice sort of uh, three rubber, uh, you know, feet on the bottom, molded in as one big circular ring like that. It's got a belt clip attachment and uh, and this just comes out like that. so that's just a, um, a friction fit, uh, rubber h there and it's got all the requisite marks on the bottom. the UL stuff, uh, you know, double insulated, all that sort of jazz and uh, B Not sure what that is, but uh, designed and made in Switzerland and it I Guess it conjures up.

You know, images of this thing being designed in some mountain hut, you know, at the base of the foothills of the Swiss Alps or something like that I Don't know. and if you just lift off the battery cover here, it's got the four rechargeable batteries in here. standard uh, aa's and nice big finger H holds in there. you can just pull them out.

I Really like that. You know it. It really works quite well because you have to change these things every uh, day or two. They don't last all that long, you know, a couple of days at most.

or uh, something like that. and uh, it looks like there's a, um, there's an air Inlet there and it looks like that is. Let's have a look at that. Aha, another one looks like that's some sort of filter.

possibly something like that. So there's two. um, well. I presume they're uh, you know.

well Outlets um, sorry, for you know, sucking the air out. So anyway, um, there's two screws here. we can take those off and uh, we can I presume it'll just lift off like that. and I expect there to be.

you know, a motor in there with the suction mechanis. That won't be very exciting I don't really want to I don't really care about that. more interested in the circuitry and why it's failed. Actually, because it actually does absolutely nothing.

The power doesn't turn on. Yes, the batteries are good, so you know I Really want to find out why this thing has failed and let's have a look at what we've got here. I expect it to somehow separate? Oh yeah, yeah, who? wa yep, no problems whatsoever. Oh, look at, that isn't that isn't that neat.

I Rather like that, look at the cable management in there. They've really there's that's not one. that's not some slap together one. hung low cheapy, that's for sure.

And uh, as you'd expect, you know this thing is, uh, you know, the uh, the, you know, the top notch. the duck guts rollsroyce of breast pump. So that's rather there's the uh yeah, there's the rubber membrane on there. We've got three, uh, carbonized uh, conductive contacts there.

Nice. They've put three and that looks like really good quality gold plating on that board too. They've got white solder mask on it, but the gold plating looks thick and high quality as you'd uh, expect. But what? I Really like here is this: Cable Management Look, it's all molded.

This is all looks like one big molded plastic piece and they've gone to the effort to mold in all the individual uh, stress retainers there and management. For The Individual Wires coming out. They've cut them all to the exact length. Look at that.

They've put little hooks under there to, you know, so that they're actually you know so that the uh wire doesn't flap around so it doesn't get caught when you put the when you put the top on and get pinched and things like that. I've seen so many products fall down in that area actually where they just have loose wires running all over the place and then when you assemble the thing, they get pinched. or you know? H It's just horrible. but this one is beautiful.

Look, it's exact length. There's another cable management hook there. Lovely. Oh man, it's beautiful.

I Really? I Just love that from a cable management perspective, they put a lot of effort. There's there's another one down in there little, you know, little pinch in there and there to keep the cable in place. Beautiful. Oh, and also clearly what they've got is there's the LED in the center of the board there.

You can see that that that's a reverse Mount LED Exactly like I have on my micro current. If you've you've seen my microcurrent. no doubt. There we go.

It's got a reverse Mount LED on it poking through the well, what this? call it the front side of the board? I Guess with all the components mounted on the back and uh, that just shines through and uses um, the rubber here as a little, uh, light pipe kind of thing. so it just shines out there. They've got the alignment holes there. they've got three of them they haven't got.

there's not four so it's not like you can accidentally assemble it the wrong way and waste time in production cuz somebody you know assembled it back to front or it even ships out. be and you know the plus button becomes the power button or something like that that that that would be a trap actually for when you have a symmetrical design like this. If you didn't have your three keys, you know your little key holes mounted like that, this could be mounted any way. You know, if you had four of them, eh, you could fail.

dismally. But anyway, let's I assume the board just pops. Yes, it does just pops out. Tada and just the board mounting is all molded into the one big plastic case there.

This is really beautiful, really solid, and the Uh PCB supports are also molded in to there as well. This is great stuff. And there's the cable management paths. Well, what we're interested in is the board and that's uh, pretty much what I expected.

We've clearly got a M main micro controller here. We'll take a look at these in more detail. Another S8 package, a six pin so uh, 23. there a couple of diodes and uh, one big uh, tanum surface mount tanum.

there another diode in there, a few odd passives, and uh I love the programming. uh Port here. this is clearly like a JTAG or an in circuit serial programming port for the microcontroller so they can screw this thing in unprogrammed and then during production, uh, process of this thing, they can just plug up their H hook up their little customade um uh, you know, probe thing here and and just uh, program this thing and uh, do in circuit uh, testing maybe as well. or you know, run some operational tests or things like that.

So um, yeah, where something on on here has failed? By the way, I'm not sure what. it's certainly not the wiring. It's not like a you know, wirings come loose or anything. these are all hand soldered onto here.

but they look hand solded on beautifully. as you'd expect in this Swiss Maid You know someone in the Swiss Alps is there rubbing rubbing their Gray beard and their soldering each one at the right tongue angle. Oh beautiful. Anyway, the quality of construction is excellent.

Let's take a look in some more detail now. One of the first things I see I just went aha this little sucker down here. if we zoom in on this because we're going to I'll look at the components, later other components but this immediately Drew my eye it's got 1.5 written on the side of it and for all the world that little puppy there looks like a surface mount fuse 1.5 amps presumably and I think there's a very high likelihood that fuse has popped and you can tell it's an input fuse here because red and black of course they uh would come from the power and they do if the they come directly from the battery. If you follow the uh wiring on the inside of the thing, we've got a diode here probably uh in series or reverse protection I'm going to have to um check out the tracers on there bit hard to see the tracers with this white solder mask on here.

One of the disadvantage was disadvantages with white and black uh solder masks. um they you know they can be difficult to see the tracers through there makes it you know harder to reverse engineer and Trace things out when you're troubleshooting like this. considering that absolutely nothing happens to this thing um when we attempt to turn it on, it's likely that something has gone wrong there and there's no obvious signs of, uh, failure anywhere else. But look at that medila.

They've got their own branded chip there, and of course they wouldn't have designed. You know it's not going to be an Asic I Greatly doubt it. it's just going to be an off-the-shelf micro controller I would presume, which they've uh, you know, they ordered so many of them, they just got them custom branded direct from the manufacturer. and uh, let's have a look at what this S So8 is.

Perhaps an E Prom or something like that and no surprises at all. 24 C1 Is it clearly an E S external E prom for holding various Uh settings? That means that they've used a really lowcost micro controller here. You know it's not going to be a pick, or like, you know, a new model picker and app Mill that has built-in uh E prom or something like that, it's going to be, you know, a real cheap, you know, 8051 or some other, uh, obscure brand and it's a sweep elsewhere around the board. They've used large Footprints there for the components.

Really nice. You can get in there and probe those beautifully. I Like that rather than little tiny Footprints cuz they're not. You know this is not a dense layout so they don't really need to do that.

There's the there's a 100 mic, uh 10vt Tanum and a couple of So 23s. They're probably uh, transistors. There's another six pin, so 23 up there. Don't know what that is.

Could be a a voltage regulator or some such. Not sure although why it would be all the way on the other from the the other side of the board. from the Uh battery input here I don't know. Um, actually I don't see a voltage regulator around the input.

Oh no, it's probably there there. Yeah, sorry, that one. There is probably a voltage regulator, so your power probably comes over here, flows over to your voltage regulator and uh, that's that. and they've got it.

Curiously, they've got a M resistor here A M package resistor whereas in all the rest of it there's just using standard, you know, 0805 package resistors. But they've just got one which is a mou and clearly they've gone for that M package because it's physically bigger and will have a bigger power dissipation. So you know, instead of using a big uh TW like a 1206 or even a bigger uh, regular surface mount package, they've gone for one of the old style Ms which You Don't See Much Anymore So that's probably a current um, uh, sense resistor for the motor so it can uh uh, you know, so the software can actually monitor how much current is flowing through the motor so they that would dissipate, you know, a fair bit of power more than a little 0805 or something like that could uh, tolerate. So they've engineered in a larger physical package and on second look, that's actually 6.8 ohms and uh there.

It doesn't seem to be used as a current sense one. I Can't see any uh sense lines actually coming off that so it just looks like it's a series resistor there and there's your reverse Mount LED sort of in a reverse go Wing type uh package and uh, that just shines through the hole in the board? Easy. There's a little bit of residue left on the hand solder joints there, but they look fine and there's no obvious signs of dis stress in a component. I don't see any blow holes.

you know it's not like the you know something is uh, charred and uh I've given it the smell test and I can't uh smell anything wrong with it. So I'm going to I think I'll bet my bottom dollar that fuse is popped all right. So let's have a look at that and get in here and probe it. Bang There we go.

That was my finger there and yep it is popped I that is I'm pretty darn sure that's a fuse and it is open and by the looks of the traces on there, this is a reverse protection diode after the fuse there. so the neg. so the negative will be on the top side here after the fuse. So we basically got the positive power coming in through the fuse and then so this is the rail part here and then.

this reverse protection diode here. So the negative will be on this side. So let's probe this and see if this is popped. No.

There we go, it's still 45 Vols Not a problem and if we do a Dave CAD drawing here, we've got our battery input like this: positive on the top side going through a 1.5 amp fuse. pretty sure it's 1.5 amps cuz 1.5 is written on there and uh, that will then have a reverse protection diode going to ground like that. So if you plug this battery in back to front if you end up with if you have the positive here and the negative up here, then we'll get current flowing through the diode and then your circuitry over here is only going to get a maximum of you know, 0.4 volts. That'll probably be a shot key or something like that.

0.4 Vols So circuitry is all protected. Um, and you're going to get a high current flow through like that because this thing is powered from rechargeable batteries. So um, they're capable of, uh, delivering large amounts of current that would certainly exceed 1.5 amps. So if you put them in backwards, you're going to pop your fuse and all your circuitries protected of course.

But then, well, why you've popped your surface mount fuse. So I don't know why they didn't like use a resetable Poly switch there, or uh, something like that. It certainly looks like like a oneof fuse. But in, in any case, it certainly, uh, failed.

that's gone open circuit, which is why our thing doesn't work at all. So um I don't know if it's you know, human error. They put the batteries in backwards and this thing is just cactus in if that's the case and that's bad design. Um, really, you know I mean it should only be for gross overloads of the load or something like that.

Um, it shouldn't uh, blow when you just insert the batteries the wrong way around. That's crazy. So usually to overcome that, of course you just have a standard uh series diode in there like that and then and then that goes to your load internally and then if you reverse the batteries here, no current flows at all cuz current can't flow back through the diode and well, it's fixed. but they haven't They've used a reverse protection diode.

Hm. Now the big question is, of course, what caused the fuse to blow? Was it something in the circuitry, has the motor done something that's caused that fuse to blow? or is it just you know, the batteries have been inserted. uh, backwards, You know, and uh, and it's just popped it and it's bad design? Who knows. But uh.

anyway. um, one way to find out is to uh, uh, replace that fuse and uh, give it a go. But there are dangers in that if you just, uh, short that out and do it again and something in here is shorted well, you could blow the circuitry. I Mean the fuses there to actually protect your circuitry.

So really, you know you. What we have to do first is check that there's nothing shorted on here and the first thing you want to do is check to see if this power rail is shorted to ground and we'll do that. We're going to put our negative Probe on here. By the way, if you're probing stuff like this, there can be flux residue left on these pins.

That's why Sharp Probe is important. You've got to actually Pierce any oxidization or residue even on your components as well. Oxidization? Um, is a big problem. when you're troubleshooting, you can't You can easily make bad contact on there.

But anyway. Let's uh, measure that. No it? Uh yeah, that's a typical cap. It's it's going down, but that's you know.

it's certainly not shorted, so there's nothing wrong with the input power rail there at all. And the next thing to do is just probe around some of these capacitors on here and see if any of the capacitors are shored cuz a few of them are bound to be across the power rails. I Mean we've measured the input to presumably the voltage regulator over here and that was fine, but you know we can do some more probing around here like we can. You know, measure across that cap across this one here.

oh 13 Ohms, but that's probably that's you know, that's probably the motor or something like that. So probe across here and I don't see any, uh, any gross fires. You know there's a couple more around you probe around, but uh, if you can't find any shorts across any of your caps, then uh, you know it's It leads you towards being fairly confident that, uh, the input fuse has just, uh, popped due to a reverse battery or something like that. and it's probably not something at least on the power rails in this thing that is pop that fuse.

So what I'm going to do is pop that out I'm dual wielding soldering irons here and uh, that's the easiest way to do this and I will just pop this sucker off. Bang, it's gone. What I'm going to do is just solder on a couple of little pins onto here so that I can insert my Am meter in there there and I can measure the current going through this thing when we Power It Up All right now, what I've done is I've hooked up the two test points: I've got some alligator clips here going to uh, my fluke Amer here and we're in microamp range here and I've plugged the batteries in I mean ideally. um, well.

sometimes you want to do this test with like a bench, a current, limited bench power supply. but I'm pretty confident with this thing I couldn't be bothered Hing it up. So um I'm going to, um, be a bit Brave and going to use the uh existing batteries here. and uh, try and get um, the peak current of this thing now I've got it switched off I haven't switched it on yet and it's drawing about 150 microamps.

Um, that that would be the microcontroller? Uh, just you know. Switched Off waiting for those soft buttons to be pressed and that's and that's pretty high. Um, in the schem of things, you know, you can actually get a lot. Uh, better than that.

But really, you don't need to. you put the batteries in this thing. it's used practic. They rechargeable use practically every day.

So you know, really, you don't need this thing to last for, you know, years or decades in standby. So that's just fine. So really, what we want to do now is change our current Jack over to 10 amps. Yeah, beep beep, beep Bloody default AC Current: G This is an Electronics multimeter bloody H industrial thing.

No, they claim it is, but they got other meters for that. It's really annoying. Um, right? So what we're going to do here is we're going to switch our uh Minmax mode on so that will capture the maximum. It can capture Uh pulses much, or spikes much faster than what the display can update.

So that will, uh, capture that and uh, hopefully give us our Max current there and uh, let's which button is which? there There we go. that's the power I don't know what? um, suction setting it's set to I haven't I've got the tube plugged in so that we can actually uh, you know, short out tube if that's the correct terminology, plug it anyway. we'll use that and uh, that should increase the current draw. But here we go.

Let's see what Peak current we get and presume and hopefully it works. Gee, you know that's the main purpose I want to fix this thing? So let's go. Oh Bang Bang There we go. It's working.

That's all it was. You can see the LED flashing there, no problem whatsoever that seems to be working fine. I won't plug the tube up yet cuz I Would presume that'll increase the current. but let's uh, let's have a look at the max reading there .56 amps is what it was.

Uh, is the maximum reading the minimum and the average is you know? H 68. Who cares? But the maximum value there is 056. So let's um, do that again. with let's just plug this up and I think we'll find the current increase.

Sound has certainly change we you? You heard it beep there. So it's obviously got a new maximum Peak value there. So there it goes. Again, it it beeps when it it detects a new maximum value and oh., 58.

No, no, that's terribly unexciting, but there. you go. that's uh, it's fixed it so looks like it was only the fuse that was dead. of course that could be on minimum suction too.

So there we go I Can hear that. Wow. really ramping this? That's probably that's probably Max now can really hear that. So let's it's I think it's still going to be very, very similar.

Yep, no drama. but it certainly increases the uh suction on that thing. and there is suction there. It's really good.

It's working. A treat. It's just switched to another mode it's got. That's why it's got a micro controller in here and it's got I don't know, scientifically proven to, you know, suck out the most milk I guess it's got all these different modes and it does seem to switch between them.

so and it's not flashing anymore, it's just uh, going single. but I'm sure if I read the user manual actually uh, was familiar with how this thing worked I'm sure that is all normal now. I don't have a replacement uh fuse for that to hand so you know the best. I I sort of seem to have is one of these axial uh 2 Amp uh Slow blow types eh, whatever.

it's better than just bdg it and and uh, shorting it out so I might just to get it back up and running today which is what I have to do I'll just uh whack in one of these. and if you're curious to know what rail is being used in here, let's probe one of these caps down here and we get in 3.8 volts or thereabouts. so it looks like oh oh, accidentally pressed the button there started it up. There we go so it looks like it's a 3.8 Vol rail there? it's not, uh, your traditional 3.3 for example.

So I deem this thing to be repaired. but uh, that's not the end of the story because um, we want to, at least, uh, have a look at the motor underneath this thing. I mean I don't want to take it fully apart? It won't be that interesting. so let's see if we can pop it off in what it looks like.

Aha down in there. look at that little clip down in there. it looks like it. it, uh, joins it.

uh, clamps this top half to the bottom half there. There's probably a matching, yeah, matching one over there. So if I get in here. Pop Goes the Weasel There we go.

lifted that one up. Give that a little gentle prod. Aha. Tada oh oh, that seems stuck.

There's something something not. There's our motor. Tada there's our motor. There's something not.

Oh yeah, there's the uh Yep looks like that's the uh, little plastic, um, rubber, uh air hose there. So oh yeah, they're actually joined onto there I don't want to take that apart? That'll be annoying to. Oh, actually just popped off. So, but there you go anyway.

that's the uh, that's the motor. Not very interesting with the uh and it just generates suction in there. So I'm not going to tear all that to bits. This thing's fixed.

and uh, hopefully that plug needs to go back in there anyway. Not terribly exciting. And if you actually look at the uh wiing here, we've got two larger gauge wires here, which are clearly the Moto drive and there's two black ones as well here. um, thinner gauge.

Obviously some sort of, uh, sense, some sort of sensor or something like that coming back from the suction mechanism. That's uh, that's what I would presume. Anyway, and if you're curious to see the way motor drive waveform as I am, let's see if we can probe it here or switch it on. Here we go.

Whoa. hang on, Look at that. That's interesting. Wow, look at that.

We've got some sort of variable pulse width modulation thing happening there in packets like that, so if we stop that, we can zoom in and see that that, no, that's pretty consistent. Then there's packets of those so 1, 2, 3, 4, yeah, 4.3 milliseconds and and then it switches off. of course, during those periods, so we really slow The Sweep speeds down. We can see it switching on, then off, and when it's on.

That's what it's That's what it's doing. And now what we're looking at here is the sense: uh, wave for all that sense wire coming back. So there's a see those spikes. We got some overvoltage spikes there.

If you can see those happening, we can capture on those. of course, move the trigger level up above here and we can. uh, single shot capture one of those. There we go.

So let's let's have a look at that t look at that Beautiful. Let's turn the trigger back, trigger level back down. So that is. Um yeah.

I It's some sense winding coming back from the pump mechanism, the motor SL pump mechanism and if you want to see both of them, the top waveform there. the green one, channel two is the motor Drive drive waveform and the bottom one is that sensor or something. Whatever it is line coming back. So we single shot capture that.

Bam. So that's rather curious. You can see that when the pump stops when the pump. actually this is the point where the pump stops, it's you know it's going through, its Cycles here and then it stops for its you know, 1 second or half a second or whatever.

Then the sensor is normally High when the pump's on and then it starts to rise up and give a Pwm output like that I assume it's an output and it's not. uh, some input waveform to something or rather and then that starts to rise and it levels out until such time as it starts up. Again, let's capture a big length there. There we go.

They're exactly exactly opposite. So I'm not sure entirely how these things work, but maybe that's actually an out. This waveform is not actually a sense input. It might actually be an output going to some sort of valve or something like that, perhaps.

But then, why would you? Why? Why would you, uh, you know, uh. pulse it like that. Why would you actually do that? I don't uh, don't quite understand. So if you've got a a better idea of exactly what's going on there with that, please, by all means, leave it in the comments or on the Forum There you go, That is a repaired medila.

Where is it? Medila? swing, breast pump. Um, not the world's exciting most exciting repair. Sorry, it turned out just to be of the fuse. but anyway.

I Hope I made that as interesting as possible for a blowing fuse Anyway, and uh well. if you like the video, if you like tear down Tuesday Please give it a big thumbs up and if you want to discuss it, jump on over to the EV blog. Forum Catch you next time.