Hi I Thought we'd take a look at the first return to Eevblog Bm2 3:5 multimeter. Um Frank actually bought one of these. he's in that Jacksonville in Florida and unfortunately he got it and it didn't work and he's um, you know he described all sorts of things in that, um, it would you know measuring say a 1.5 volt battery and it measure 0.6 volts and then as a drift down to zero and and all sorts of stuff. weird things didn't work at all and I've sold I Think over a thousand of these meters so far and this is the first one that's reported any issues like this at all.

So yeah, you expect this sort of thing to happen. even though each meter is individually are tested at the factory. It has to be because it has to be calibrated at the factory, so each one would have been tested. But you expect some sort of infant mortality rate on virtually any product out there.

It's not just this meter, but any electronic art product. There is going to be some percentage of failure rate. um, after they're tested and they hit the field, It's just you know the way it is for whatever reason and that's no reflection on the quality of the thing. or well, it could be okay, but in this case, sold over a thousand.

No problems and this is the only one, so you know, who knows. Murphy's Law uh, where we've got one, We got one and sorry, my voice is still terrible I Haven't made any videos this week because um, yeah, I Just yeah, you don't probably don't want to see me on camera either. So I look and feel pretty terrible at the moment and give me follow me on. Twitter I am breaking in all sorts of ways I've busted my ACL joint in my knee is completely busted anyway.

um as the probes. so yeah I might have to get surgery on that. So yeah, I'm doing wonderful at the moment. They turn to wrap this puppy and have a look and see if I it's repeatable.

Um, but the I'm pretty short. You know from the stuff he was saying, it was pretty obvious that this thing was dead. So let's turn it on and see what we've got here. Switch on.

He said it worked on AC Curiously, now that you know, function wise, it's it's displaying the right stuff. Okay, so there we go. Okay, no drama at all. I've got a I've got my Voltage art reference here I've got it set to a volt.

This is my lab referent one of my lab reference standards so let's plug it in and um, see if we get a Volt. Why? Why? Why? why he's right. Look, it's going down and down. It's not like it's on AC mode, it's on DC mode.

And sure enough, I mean if I bring in good one over here and of course it will la measure a volt. No worries whatsoever. So um yeah, that is one sick puppy. What is wrong with it? Well, let's maybe whack it on Ohms here and disconnect that.

And okay. Ohms works. Oh no, that was continuity that was cut Oh cut nuit e mode look Nope. Okay, Ohms is just showing direct short.

That's interesting. That's interesting. I Will It's got it. Maybe there's some sort of solder short on the board or something that's causing that? I mean obviously our chipsets working fine and there's not much in this apart from a the multimeter chipset that's pretty much the only active circuitry and the LCD driver chip.

The capacitance? oh, that seems a bit high 30 nano Farad's I'm not. Hang on. I've got a reference cap here. Here we go.

Let's check it out. I've got myself a em. These are very nice if you can pick them up on ebay cheap. They're old, but these are Co standard capacitors.

They're very, very nice and and often get them quite cheap. Ah, that's low. That's low. Put it over here.

but at least it's functional. There we go. No dramas whatsoever that's well within spec. So yeah, this one is a bit there.

And I've checked other meters I Think that is. Yeah, so this one's a bit low on cap. Let's measure some current, shall we? Here we go: I'm feeding in one milliamp. Current range works.

Current range works. Ten milliamps, Hundred milliamps. Hey Okay, that's interesting. That shows that well because the the current uses a different input arrangement.

So yeah, there's something with that main common terminal which you know is maleic. so it's not the chipset. It's not like I Don't know ESD or something else has gone wrong with the chipset and it's damaged because the current just works fine. Let's try the micro ampere range.

100 micro amps. There you go. Yep, it works just fine and dandy and hold on to your hats. The Millivolt range works fine and dandy as well.

So um, yeah, that's interesting. So Millivolt Range works. Current ranges work so chipset is just fine, but all the other functionality like if we go back here to our volts, you know, like that is that is dead and let's just jiggle the range switch around here. jiggle is a technical term and it's not that, so looks like something on the front end of this thing is gone on particular ranges.

The Millivolt range is basically straight in. It doesn't go through the input divider or anything else unfortunately. I Do not have the schematic for this Broman Will not release it to me. they say its proprietary.

Bla bla bla. Yeah, okay, fair enough so we don't have that, but hey, we can at least have a look around. Let's go the serial number for those playing along at home and we're in like Flynn Unfortunately, we're gonna have to take this top bored out here. That's one of the downsides of having the cat for raiding in such a small meter so only way they can physically do it and that's where a bit of the input circuitry is around there.

but we can see other stuff on here and I might actually get out the Takano microscope. Just get the two side-by-side and see what we can see. Oh, and the other annoying thing about having the secondary board here is because I do have to actually de solder this and unplug It has essentially unplugged the jacks and everything else to get in there. We can't sort of like feed in stuff and then measure it on the main board underneath at the same time, so that's what you can if you go to a lot of trouble to wire it back in and stuff.

But yeah, it just makes it a bit tricky to troubleshoot. But the first thing you do with troubleshooting something like this is visual, especially if you've got a unit to compare it against. Alright, let's check this out. We've got our unhappy camper on the left here and our happy camper on the right.

and probably just a just because you can do a quick visual inspection to see if there's any missing parts. Now this you know shouldn't be the case because as I said, it would have passed factory test, factory calibration, everything else to do that, it would have had to have everything in place. but I don't know something might have made the poor contact and then in shipping it might have vanished or something like that. but I obviously can't see under the input board yet, but it doesn't look to be any issue here at all.

I wouldn't expect that but see the nice little ah star grounding point there. Very nice just going off. Someone knew what they were doing in terms of PCB layout but yeah, there's nothing obvious going on there at all. As I said the main chipset down here which is a BTC which is bribe and Technology Corp branded I don't know exactly what what it is.

they won't tell me but that is obviously not failed because half the functions work and the other half don't So there's got to be something screwy with some with something to do with the input so that all looks hunky-dory The other thing next thing I would look for is any shorts like a little solder balls or anything like that as part of the production process which could have got in there and they may not have been an issue during the during the process. I Love my Takano microscope here. It's beautiful isn't it? Um and all the way in and go all the way with LBJ Look at that you can see the silk screens actually a dot matrix printer. It's not a photo image of all silkscreen.

you can see the dot pattern on there and but yeah, I'm solder balls. They could um certainly account for it as part because they're like sort of like a little unknown theme. got slightly too much paste. you know it's not exactly the same every time, even though you know there might be a smidgen over or just how the you know the dynamics of the paste and everything else and how it melts and things like that, you can often get a stray solder ball.

So I'm just looking for anything obvious like that and I'm not. So I wouldn't expect to see it up the top because this is like as I said, this is the LCD chipset. All right here we go. Here's the top board.

we've got our here's our voltage input. of course there's two input protection resistors I can measure those of course there 1k could our blonde brown, black, red there and I Don't think it's going to be our Ptcs here because otherwise we wouldn't get anything. But anyway, oh, that got a little and somebody's had a little crimp. No, no, it's all right.

no worries there. but we could measure those. They should be about a K each or something like that. But as I was like if it wasn't broken like that, doesn't explain like the zero ohms and things like that and the mobs here.

well you know in theory it could be, but doesn't explain why the 100 millivolt range was working for example. and you know, couldn't measure 1 volt So you can measure those? They they should be open. Of course, they should only start clamping at, you know, a thousand volts or whatever they're rated for. We've got some 5 Meg input resistors here.

you can measure those might be doing silly buggers, but we've got the input jack detection stuff like that so it's not that. so there's nothing on the top board really that you would suspect I'd be going straight for down here and let's so let's have a squiz around here. And once again, I'm looking for bad joints. Oh hello, hang on.

You know Nine. is that my imagination? Hang on? sorry I may not fight. Oh no, no, that's all right. No thought, there was no feeling on that.

but it's it's all good. So I'm looking for bad solder joints I'm looking for solder balls, shorts, other things. but what's going on down there? Oh hello, hello L-3 Tada, hello. Get that L-3 has cracked.

The solder joints on L3 have cracked. We got one. Yep. Wow how has that happened That's been down wire out of the way there.

Sorry about the light here I Can I Can Here we go. it's going to be better. Wow I Thought it looked a bit askew and you go there. and sure enough, that puppy.

wow that's that's an inductor and that has sheared right off. I mean it's not like it's a heavy part, so that is very, very interesting. I'm going to. well it's gone.

Look at that. There we go. Okay, so what I'm going to do I'm going to take that out now. They put some fresh solder down on there those pads I'm going to so well I put fresh pillows solder down a one or week the other off and replace that and I think it might come good again.

The one next to it. sorry about the focus on this. the one next door. it looks, well next to it looks good.

That is weird because and okay, solder joints can crack like that, but they're usually on high mass components. so Wow I find that totally fascinating how it's able to do that. Oh Check that out. Something has gone horribly wrong with that.

That's the bottom of it. It's like got black goo or some crud on there. that is really really interesting. Wow I Wouldn't have expected like this was one of the things I was looking for was a dodgy solder joint I Wouldn't have expected a surface mount part like that.

shear off. but what is sup? something's gotta what? What on earth has happened to that? Look the beside the cap. everything else is that blowin. Wow Like there's no way that inductor could blow.

it's not. There's no way that could blow and not blow the input circuitry so that is Wow that is toast so I can't just. well I could flip it over I could flip it over and resold it back on. but jeez, you know.

flip Reese order it on upside down like that, but that is horrible. Has that just been a badly produced inductor? You can get that it's um, something's gone horribly wrong with that. Yep. I think we just have a bad inductor.

There's nothing on the solder in. Look at that. There's the there's the other half of the of the cap from the inductor and it's just yeah. we have a faulty part of a faulty inductor.

Something's gone horribly wrong with that inductor and obviously it still made contact. when they assembled this thing. it was still fine and whatever passed it. Yes, but after that, it's just gone horribly wrong.

But as I said, there's no way that you could blow that inductor and not blow your inputs so you know, not. have your input protection trip and you know blow out your tracers and everything else so it hasn't been overloaded. I Think we have a genuine inductor manufacturing fault. So there you go.

I desalted that from the PCB and that and of course, what we're dealing with here. This is actually the common terminal this wire here, even though it's got red insulation actually, it comes from the ground terminal on the front panel and they're just splitting those off different traces to different parts of the circuitry up here. So anything that relied upon this ground connection here obviously did not work. So there we go.

We're splitting some more. There's another star grounding point. Very nice. They know what they're doing there.

So what they're doing. these. you see little slots in there too. They got a little isolation slots down in there.

What they're doing with these, these aren't Well, they're not wound inductors. these are our RFI beads actually just for some high frequency rejection to like you know, pass emission standards and compliance and all that sort of jazz. So yeah, I mean you could bridge that over with a short if you wanted to. You can put in a zero ohm resistor if you didn't care about the you know the EMI requirements and things like that.

I'm not sure I have a suitable RFI beam, so I might just potentially bridge that with a zero Ohm resistor just for now and that should get us up and running. Alright, let's retest this puppy one volt and we'll We have a winner. I Think we will. We don't.

Winner chicken dinner There we go tonight. That's all it was. We had ourselves a faulty component I Have no doubt everything else will work now. if we just do the Ohms, for example, the Ohms will work.

Tada. There we go works a treat. No problems. That was the only thing wrong it was that was that RFI bead in there which I'm pretty sure that's a faulty component that hasn't happened during the solar in process.

Or you know there's nothing wrong with the solder and process. There it was. that component was crap. There was something seriously wrong with that and well, yeah, hmm happens.

so I hope you found that interesting. I'm glad we actually found that. That was pretty darn easy In the end. only took you know, seconds.

It was like one of the first things I saw when I opened that when I took that board off the back of it. So pretty easy. And we didn't need a schematic to find that so component fault. These things happen and to me, it doesn't really reflect upon the quality of the product.

If there was more than one and this was a, you know, a systemic problem, then we might have an issue. But hey, you know, ultimately you've got to trust the components that you're buying. You know the genuine complaint you're buying from the genuine manufacturer. They're all in the real.

You expect them to be manufactured properly. It's not like the the manufacturer of the meter or whatever product it is can actually inspect those parts for themselves. You rely on the fact that you're buying quality parts and well, you know, occasionally, um, you can have the odd component weird component failure like that. For whatever reason as I said, it would have been, if it was like the entire reel, the entire batch of these little lower ferrite beads that was dodgy, then yeah, there would have been.

You know? Yeah, I'm sure we would have had a lot more reports so I suspect this might just be a one-off anyway. I Hope so. Um, so yeah. I'll definitely show Broman this video and they'll no doubt investigate it and see if anything else I might open a couple of other meters I've got in stock here, although this one actually, you know I've only got the new batch so oh yeah, no.

I don't think I can even open well my current stock anyway just to have a squiz and I'll give a little bit of a wiggle on the ferrite bead out in there and see what happens. But yep. I I'd be surprised if this was a systemic problem across all meters I think we've just encountered on those weird one-off Murphy's issues anyway. I hope you enjoyed that little hunt down of that problem.

If you want to comment as always, links down below, leave YouTube comments, etc. Catch you next time. Hey, check this out. Look amazing.

Symmetrical multimeter stacking just like the Philadelphia Mass Turbulence in 1984 aren't believable. No human could stack multimeters like this. That's a few multimeters 40 to be precise I Can't explain it, but there's something very therapeutic about doing this. Oh yeah, so I've got my handy banana plug lead here.

I Go. Oh goodness, the things I do.