Hi it's new test instrument tear down time. We've got the new Keysight Edu 34450a five and a half digit multimeter. This is part of their new educational series as you've seen in the new uh giveaway of videos that I've done. and it's and probably the most interesting of the three new instruments.

They've got a new educational power supply and a educational model Uh, Function Gen 20 Meg Function Gen as well. and uh, they're both the function gen and this multimeter are in your traditional oscilloscope like, you know, short, uh, compact. When I was a boy, oscilloscopes were never like this. Uh, thick.

like. you know they're out here like this. But anyway, the oscilloscope form factor. Uh, basically they're uh, reusing the tooling for their Uh 1000 series.

Um, oscilloscopes at which you can get like an Edu version of the oscilloscope. And the whole idea is that they provide these four instruments for the educational market as all part of one big educational package so that you can equip a typical bench. So I thought this is probably uh, worthy of the first teardown just because it's interesting. um, form factor.

So let's check it out. First of all, you may have recognized the number. the 34450a. They're actually reusing a product number you can.

Oh well, you used to be. I don't know if you still can, but you can buy the 34450a five and a half digit multimeter and it doesn't look anything like this. It's a big oled uh display one and it like, why? why reuse it? Why the confusion like that? I like they didn't even call it B or anything, but it's got the edu on the front. so having the edu on the front exact same part number.

it's a totally different look and feel instrument. Ah, I don't get it, but it's 696. Uh, us dollars. So yeah.

anyway. um, it looks like an oscilloscope and you can see that they've reused the tool in here because it's got a fan outlet here. but there's no fan in it. So yeah, Lan and uh, Usb as standard.

Well, you're either going to love it or you're going to hate, uh, the form factor. So yeah, whatever. Anyway, you know what we say here on the Eev blog. Don't turn it on.

Take it apart. Except Flatheads. not going to do it. Hang on.

Is it a five and a half digit? Or is it five to the power of a half digit? Hmm. got that self tappers into plastic down here? That's not pretty? Well, they felt for all the world like self-tappers but they weren't metal threaded inserts. they just had lots of loctite on the bottom of them. So don't get your fields versus reels mixed up.

so it looks like we've got all the basic uh shielding you expect Whether or not this is identical to their uh, oscilloscope? I can't exactly. uh, remember offhand, but sucker should lift off. Yep, we're in and there you have it. Whoa.

Isn't that nice? That looks pretty. Schmick. Got our processor over here and our multimeter measurement capability on a separate board. Very nice and a good old-fashioned transformer in there.

Look at that old school, you don't see that much these days. Ah, brings a tear to the eye. Anyway, I do like the cable management in there that looks pretty groovy. I'm not sure what the deal is going on there with that connector.

With that like inline spay connector, it's all terminated very nicely. doing all the right things. All your groundies down there I'm sure there are all lock tighted. Uh, we've got ourselves a ferrite on the output here and big ass earth going over to uh, the processor side of things because of course all your multimeter section is isolated.

That's why the only thing going over here is this and that Guarantee that chip right There is an Opto isolator, so obviously not many uh connections. It's a complete serial interface. It'll be reasonably high speed. Uh, Optocoupler? We've got our big shield over the measurement.

Uh. front end got some good old old-school relays. I can show you a little uh quirk of that. Uh, at the end, when we, uh, power it up, check out the front end.

This actually looks really good, doesn't it? I'm actually, uh, quite surprised to see the uh, banana jacks soldered directly onto the Pcb. There got a couple of isolation slots cut into there two gas discharge tubes. Gdt's thank you very much. Uh.

two big ass mobs here. Look at the size of those monsters. Um, what is that? I forget what the rating on this thing is. It's it's only Cat.

Two, Uh, with the 300 volts, which is common for bench multimeters, you almost never see any bench multimeter above Cat 2. It's just a thing for them. But ah, geez. look at that.

That's pretty juicy. Tell you what? Look at those big ass deities over there that'd be across your uh, fused your current shunt fuse and there's your fuse right there. So that'd be uh, back to back diode protection. You know they often do that with a diode bridge, but in this case, yeah, they're doing that with two big ass back-to-back diodes.

Wow. never seen one so large. I used in a multimeter before so that's pretty nice. Um, yeah, and the fuse.

They've gone to the effort to wire this thing over, so you know they could have maybe chose a Pcb solution there, but they haven't. They haven't. Uh, skipped. I I don't see your traditional current shunt.

Okay, it's got to be these bad boys here. You traditionally don't see that. you usually see your bent, uh, like Nichromey type wire current shunt. Um.

Anyway, we've got a range relay here and there's really not much doing over here. These are just our voltage regulators. Just start powering some of the logic and stuff so nothing to see there attention to detail. They have, uh, someone had fun with the silicone gun.

Look at that. They gunked it down nice and we'll be. yes, I'm still waiting on hold if you can hear that in the background. Anyway, quick look at the Uh processor board here.

and now you've got to think that this comes from another one of the instruments, because obviously they have some sort of uh, B and C over here. So is this identical to like the Function Gen board? Hang on. Let me check the function. No, that's interesting.

Both the Function Gen and the Oscilloscope don't have anything in the way of a B and C there. And of course. uh, look, you can see up on the metal work there. They actually have the B and C on the back like that.

Um, maybe on the Function Gen version of the oscilloscope. I think. uh, might have that bit. obviously reusing that processor board as you'd expect, like they'd be.

you know, crazy not to reuse the same board. But anyway. um, the earth wires. Just they've just soldered it into there.

It's Nikon bugger it. We need to, you know, get a big ass earth wire over there. and well. that's one way to do it.

There's nothing inherently wrong with that. Anyway, I won't bore you with the details. There you go. you can read that for yourself.

St Arm Micro one variant it is. You got the memory and you got the flash and you got the whatnots. And uh yeah, not much else we're gonna. There's that the Ethernet? Yep, and uh.

Usb? Um, and well, not much else There you go. Is that the Lcd flat panel driver? I don't know, It hasn't got many connections, has it? But yeah, it's really not much happening there at all. And well, you wouldn't expect anything more. And if you have any doubt that there are reusing the metal chassis there, well, there you go.

There's all your inputs for your uh, four channel scope. Nice. Well, you know, why not. All right.

So taking the cables off, taking out a bunch of screws and gotten rid of the fuse holder and that should just lift out. Careful with the banana jacks, they've got to lift out vertical and tada. there you go. There's the flip side.

Oh, we can take the metal shield off. Very nice. Check that out. there you go for you jack aficionados, there's none of that uh, split jack rubbish.

This is interesting. They've got a sneaky little bugger ferrite bead there. Here's it. You can see the trace.

this is on one of the inner layers, but going off like that and it looks like it's going under the ferrite bead. Yeah, okay, it's only Cat 2 Raider. But yeah, why you'd just rely on a layer for that sort of, uh, insulation. Beulah Bueller Beulah.

what the heck is going on here? Uh, it looks like like some sort of, touch switch. But it's not because it's like it doesn't actually connect to anything As far as the case goes, It's like around about here on the case. it's just like it's not that. So I can only think that it's um, some sort of elaborate, uh, you know, open air Pcb spark gap.

But what does it connect to? Oh, like Mains Earth or something. Uh, it? It could be. it could be. I'm gonna have to buzz that out.

Um, that would be my only guess because it's nothing to do with the inputs. Not like some spark gap because they've already got like real spark gaps here. Um, it's nothing to do with that. But here's the thing.

Um, neither side of this actually connects through to the shield here. and you might think, okay, it'll connect down through to the chassis, ground through one of the uh posts here. one of the mounting studs, right? But look, there's your isolation around your stud there. There's your isolation around your stud there.

Uh, that one. That one. The only ones that are actually have something connected to them are these two down here. Sure enough, there's a 100 ohm resistor to Mains Earth there.

So where's that? Where's that going? Yeah, okay, we've got 100 ohms in series with a mob here, and in series with a spark app. and then that bug is off Yet then that goes, then the other side of the mob. So you got a spark gap and a mob in series by the looks of it and that goes. So that's your positive input terminal, that's your in ground input terminal.

but then the other side of that mob goes over to this spark gap in series with yep, series with this mob which goes to your 100 ohm resistor which then goes to your mains earth. So there actually are overload clamping that down to mains earth. Nice By the way, all the input switching relays here. they've all got isolation slots between the coils and the contacts.

Nice touch. And here's a nice little touch there. your three slots for your shield. I just unscrewed it there and you'll notice that this one will slide over and these will slide over like that, then it just drops out.

Nice design, right? So there's our big ass Ac input coupling cap for Ac measurements here. They've got a catic resistor divider here, so that's for the ranges, so no, you know that's what you expect. You expect that in any five and a half digit uh plus class meter you can't Well, you can do it with discrete parts, but it's just. it's much nicer to do it with a ceramic array, so no surprises there whatsoever.

Uh, here's our two uh input strings here. These are for the Uh sense lines here and of course they whack them in series for uh, extra voltage standoff of course, because each one will be a couple hundred volts and well, 200, 400, 600, 800, 000 volt rating. All right. So it looks like this is our another input string here and that little inductor there let's jump over the via for that is there.

So that's coming from this relay here. Classic Uln 2003 relay drivers here. and they're buggering off to drive our relays so you can see We've got our coil side here and here's our measurement side. So oops, Oh there you go.

You got one sneaky little bugger coming off there and going through. Can we see other sneaky little bugger tracers going off? So yeah, this is interesting. On the Uh contact side, I'm not seeing any parts on those relays there and on the bottom side down here you can see some internal traces there. but apart from that, not much doing is there.

It's nothing exciting to see there. All I can see is this little one buggering off over to here. Just one thing I notice here. Just from a routing point of view, you can see these are going off here to drive the coils they drop.

They're on the top layer here, tracers on the top layer. They bugger off to an inner layer and just go over and drive the relay here. Oh whoa. Why I'm not seeing it from a voltage.

Um, like a clearance? Uh, creepage reason. So they're doing it again here? I don't know. Oh no. Now I see you're probably screaming at me in comments.

It's very faint. You can see this is like the Ac couplet. No Ac coupling caps here. But here's another input resistor here.

and it's actually going on an inner layer under these two resistors here. And um, over to one of the contacts on this side of the relay. So yeah, that's interesting. Why run them under something that's clearly on? You know you want your? once again, they're relying on the thickness of your Pcb layer there for your uh, voltage clearance? I'm not sure why you'd do that, right? So we've got our four relays here and our four inputs.

This relay here connects to the Ac coupling cap. This relay here connects to a 100 ohm uh resistor there in series. This relay here actually connects through to the uh, high end of the ceramic resistor divider there. And this relay here connects through to, uh, this high voltage resistor uh, array here.

So there you go. There are four separate choices for our inputs. Um, yeah, I just. I just don't know why they've gone under the why have they gone under the resistors? I don't know.

Okay, Dave, tell us how you would have done it then. Well, okay, um, clearly I would have, uh, well taken or these would have stayed on the top like this. They go directly over to drive our coils over here and then I do what we what you're doing here. Uh, the contact actually comes through the center here like this.

and then I would have put an isolation slot here and here so I could get because these are our contact size. So this is a double pole, double throw switch. We've got one switch here which connects between there and there and there and this one here here and here and here. And yeah, I would have did or taken them out around like that and then put the isolation slots in there, but they haven't.

They put isolation slots here and here and then run the trace under there and relied on the uh thickness of your layers between your Pcb? I? I don't. I don't get it. Anyway, here's the interesting bit. Check this out.

They've got a Keysight custom jobby here and we haven't seen this in other Keysight bench meters. It might be in the other because I haven't torn down the other five Double, uh, three, double four, five zero A the one with the oled. Um, maybe you know, maybe it's an absolutely identical uh design to that one. They've just changed the form factor and the user interface and stuff like that.

Anyway, you can see the little exposed guard traces there. Of course they do that for leakage reasons and you probably have to do a video on that dedicated to that one day, but you know we're seeing that on uh, low measurement. uh stuff. you know You see that in your you know, Femto amp amplifiers, and all sorts of stuff.

Anyway, I don't know if it's genuine keysight, custom silicon, or whether or not it's a rebadged one of your traditional multimeter uh chipsets. That would be interesting to find out if anyone uh out there and I'm sure there will be a lot of people interested. Um, we'll I don't know, check out the pin out of something like that. So hmm.

high-res photos on the Eev blog flickr account link down below. So anyway, that's going to contain our uh, Adc? Of course, that's you. know your traditional multimeter. like a dual slope or multi-slope integration converter.

It's going to have the range switch and it's going to have all the other functionality for resistance mode and capacitance mode. and you know all the other stuff. So that's it. Yeah, that's your traditional multimeter chipset.

and really, there's not much else doing where the relay drivers. As I said, what's that one and that's just a Dg412r mux, nothing doing there. What are these bad boys down here? and a couple of Lm393 uh, comparators down there, but uh, do we have some yet? some just some bridge rectifiers there, nothing doing uh, someone will say what's the brand of the electrolytic cap jh I can't say that rings a bell and before anyone screams, oh, there's no Ptc's in here. Um, did they got the mobs and the Gdt's and everything? Well, no, they've got one down there.

It's um, on this input string here. Of course they don't need it on all the input strings because, well, it depends on the functionality that they're trying to measure. But anyway, let's have a quick look at the input circuitry around here. Once again, we've got a couple of uh, 393 comparators there, a bunch of uh Ds for diodes.

They're not transistors. Uh, yet. Yeah, they're all diodes. So a bunch of, uh, diode, uh, protection and whatnot, and just a bunch of passives.

And of course, all your multimeter aficionados are asking the one question, sorry, I had to get this far into the video before you saw it. Um, the voltage reference Of course. No, this is in the six and a half digit meter, so you're not going to get your, you know, Ltz 1000. Sorry, um, you're going to get a Renaissance Jobby, although that's got a fair child on there, but you know it's all Renaissance these days.

I don't know who's gobbled up who. Um, Anyway, it's the 21r09 and this is voltage reference available in different uh, voltage, uh, standards and it's no like 0.02 percent at best initial accuracy. But of course the initial accuracy doesn't matter because you can calibrate that out. What matters is the uh drift of the thing.

the P: How many ppm Telus ppm Seven ppm. So yeah, debate in the comments down below whether or not that's good enough. Is it good enough for a five and a half digit meter? Is it overkill? or is it just adequate? And then we've got another arm processor there. We've got a buzzer up here for your continuity.

We'll uh, test that now because there's nothing left. really. Um, yeah, I mean, you could probably hack away there. There you go.

There's some headers. um, don't have a connector on there. They've been a bit naughty, but anyway, the Jtag's there. It's all labeled, so knock yourself out.

So the conclusion on that is that, yeah, it's pretty schmick. They've got. You know, all the dedicated parts with the relays in there. There's you know, no sort of like, like, range switch and other uh, compromises you need to do in handheld multimeters.

So there are just separating out all the functions there and it all looks like you know, relatively good. Of course, you know, only 300 volt uh, cat to your rating, you're not gonna, of course, because this is main mains powered. You're not going to carry it out with you in the field, or to a switchboard, or you know, to some big power plant or something like that. That's not its job, but looks like it has more than adequate, uh, protection.

and you can argue away about the voltage reference and uh, and whatever. I assume it's custom keysight, uh, multimeter chipset silicon down in there. Although I don't know, somebody may have helped them out. Maybe they uh, commissioned it from one of the multimeter chipset manufacturers? perhaps? I don't know.

Is it the same? Is this almost identical to what's used in the, uh, existing Oled model? In the more traditional bench multimeter? Uh case. the one that's you know, the 34450a without the Edu on. Is it basically an identical circuit? I don't know. Never open one still works, takes a bit of time, it's gone through its cycle there.

and yep, we're in. Now here's uh. one of the quirks. The absolute first thing I noticed when I plugged in this meter when I actually, uh, got it, is that.

Yeah, Here you go. It's just sitting there. We've got to have five and a half digits measuring one point. uh, eight millivolts.

Yeah, um, it's supposed to do that. So my 786 over here. It's measuring something. You know.

you move the probes around. Done. A recent video on this. This actually spurred that recent video on the number of powerline cycles.

So I take these probes, so plug them in here. Yep, there it goes. It's doing exactly the same thing up there we go. It's just cycling through.

It's just cycling through. Yeah, it's switching. and that's 10 meg ohms input impedance. I switch it to auto which is high impedance mode.

It still it. Um, and if we go to a one volt uh range here, it just overloads because it's picking up the 50. Oh no, it didn't do it. There you go.

Oh, overload? Uh, because it's picking up the 50 Hertz. Actually, let's go into fast here because it's picking up. There we go. It's picking up the 50 Hertz noise in the lab here.

and it doesn't have the number of power line cycles set to at least one. Um, whether you're in, uh, fast, slow, or medium. It still actually does this. And if you set it to auto range.

Actually, if I untwist the wires, I think that's why it's not performing like it did the other day. Listen to that relay. Look at that. It'll really depend on how the leads are, how much 50 hertz I've got at any one time.

That poor relay. Anyway, I do have a video of of it, uh, actually doing it, uh, continuously and I sent it through to uh, keysight. Anyway, that's just. uh yeah.

something to be aware of. And from what I can find in the menu or can't find uh in the menu, there is, uh, no ability whatsoever to, uh, like set up. number of powerline cycles you got, you know, autod. It has an annoying default auto dim with a screen dims.

uh, she's why bother? There's just nothing in there that I can find for number of powerline cycles. Anyway, we do have a secondary measurement capability Dc current, so it looks like we can measure because we've got the different jack we can measure current and voltage at the same time. Beauty Continuity. Here we go.

This is what everyone wants to see. Multimeter still has to have a fast auto ranging. Oh, that's so slow. Yeah, not for an everyday use meter.

but then again, we are on slow mode. Let's put it on fast. Let's see how far she actually is Here We go. Go.

up. Looks like goes up to a hundred Meg. there. Whoa.

It's just flapping around in the breeze. there. 100 Meg. Hello.

That could be the noise that could be related to the 50 Hertz pickup. I'm sure because like you know, this is going to be greater than 100 Meg. Oh yeah, there we go. We're instant.

Oh yeah, look at that. Look at that bad boy. No walkers. And the continuity buzzer.

Let's give that a bell. Well, it's quick, but it's so piss week I can barely hear that. Now I'm in a silent lab. It's like, uh, 10 30 p.m here.

all silence and jeez. Compare that to my 786 same distance with the microphone pointed away. Huge difference. Ah, looks like it's got zero Ohms compensation so we could null that.

Oh okay. the uh. pre-math Oh, look at that. Oh, isn't that fancy pantsy zero compensation? There you go.

Look at that. Oh nice. Anyway, unfortunately one of the things this thing doesn't have is, uh, your fantastic, um. trend plotting.

Like live trend plotting that you get on the other Hp. no Hp keysight bench meters? Unfortunately, it just it. It doesn't have it. You can actually do our data acquisition though.

So you know, if we go into Dc vaults here, we can actually uh, acquire and we can go into continuous and then we can go into data log mode and we can trigger and we can have trigger count and sample interview data log on like that and the minimum sample uh, interview you can do is one second. By the looks of it, I can't seem to go under that. Okay, so if we data log on and then we can, uh, run, run, there we go. So it's sampling once every second there.

but it's not going to give us a like a display. So okay so we can just stop that. then we can go into display and we can view our log and there you go. That's uh, the uh, just the 50 Hertz input crap that we were seeing there and like yeah, there we go one to time like that.

um and that's basically all you can do and but of course you can export like you can. Uh, because this thing's got full remote, uh, capability, lan and Usb and I believe you get this software with it. although I'm not sure if it's full capability. No, I don't think it is.

No, I think it's only like, uh, the demo capability of the software or something like it No, it. needs to have there. It is. That bloody relay again, needs to have uh, trend plotting in it.

just like the other keysight meters. Come on, you've already got the software there to do it. Like how? why can't you include it? I don't know. I I know it's probably extra work to include it, but and you should get, uh, the full license to the software as well.

So anyway, so look, I'm not going to do anything more with this. I want to keep this video under 30 minutes. This is not a full review. If you do want me to do a full review, I can eventually, uh, do it and have a look.

Oh, we can have a look at capacitance here. Let's say go over. You know, I bet. Look, Um, it's like a I'm not sure I how it compares with the three double four.

For the previous three, double four, five, zero A, but well, it didn't have. uh, trend plotting I don't believe. So yeah, maybe that's what. like everything's just nicked from that and that's and that's one of the problems.

Like one of the main draw cards of the keysight bench meters is, uh, the trend plot in capability and being able to do that and not being able to set the number of powerline cycles on a bench meter with uh, you know, like, five and a half dish. Sure, it's not a six and a half digit made up five and a half digits and well, Keysight might do a firmware upgrade. They have already done a firmware upgrade since I reported. uh, the auto ranging thing.

They fixed a few things, but um, it's it's still there Because I've I don't know. I've probably got a lot of 50 Hertz here in the lab. but um, yeah, no, you can't have your relays just flicking around with, uh, you know it needs to have the ability to set the number of powerline cycles. Just set it to one or have the user option to do that and you'd never get that.

um, it just wouldn't. uh, pick it up. So yeah, I don't know. It's like a lot of people are gonna like the form factor.

They're gonna probably like the uh price point as well. It's not that expensive, but then again, it's not that far off their six and a half like their low end six and a half digit uh models and other, you know, six and a half digit models on the market. so you know. But anyway, um, yeah, there might be specials on it or something like that and it's a lot of people are going to buy it for the form factor and for the remote, uh, capability and all that sort of stuff.

You know you can script things and do everything and the hardware seems pretty decent, but I like. I can't help but think that they've just stumbled on a few hurdles. um, here and in just lacking some features that could make this a real killer multimeter. I think, um, I don't know.

Leave your thoughts down below. Am I right? Am I wrong being too harsh? Uh, no, that'll you know eat into the sales of their six and a half digit ones, etcetera. etcetera. And oh, it's only designed for the educational market.

And you know it's yeah. okay, but you know, yeah, it's probably like only like software things, really. so I don't know. Anyway, that's the tear down of the new Edu3450a five knife digit bench multimeter in an oscilloscope form factor.

If you liked it, give it a big overexposed thumbs up because of the keysight Black. Look at this bloody Keysight Black. Put my hand in there and it's just. ah.

sure, I'm a white pasty nerd, but geez, you know. Anyway, catch you next time you.