Hi welcome to the Eev blog an Electronics Engineering Video blog of interest to anyone involved in electronics design. I'm your host Dave Jones Hi it's product tear down time. Yes, tear down, not product review cuz I think I've decided for most products that again to require a fairly in-depth review. My reviews are a bit too long because they include a quite a substantial tear down as well.

So I thought I'd just separate them out into product reviews and product tear. Downs Cuz there's some people who like the shorter videos and they just like the tear. Downs So it's tear down time. Today it's the New Agilant U 1272a multimeter.

Uh, it's not that new. It's been out for quite a few months now, but it's Agilent's big push into the Fluke 87. Market They directly pitch this against the Fluke 887 and we're going into that in the review. and it's comes from the Um.

it's completely redesigned by it's not just an existing Escort design when they bought the Uh existing Escort Design Group So let's tear it down and check it out. And before I do that. just a quick peek over the unit here. let's have a look at it.

It's quite a nice design. I Really uh like the new Uh styling of it. It's designed to grip in your hand like that and it does feel really rugged and we'll go into the Uh review of it later. But um and uh I Just like to say thanks to Trio Smart Cow here in Sydney In fact, they're just around the corner from my place.

Actually, they gave me this one for review. so if you're after, uh, any meters at all, there's no point actually. uh, importing them directly from the US or directly from China anymore. These meters are now not only these, but other test gear are now so cheap in Australia you don't have to import them anymore.

so thanks Trio Smartcow, Check them out! So let's open this thing up and take a look at what's inside. Oh look, you can get the reflection of my uh boom of of my camera and there's my boom mic. Neat. They feel like self tappers to me.

They don't feel like metal inserts. Am I right? Yes. I'm right there you go. Um, self Tapper Pretty, uh, standard sort of stuff.

Um, nothing unusual there. but because the uh fusers are actually in the compartment, you don't have to worry about opening the case like you do on say, the uh, fluke 87 units. Now that was surprisingly hard to get open I couldn't actually pry that end off I Had to sort of lever it up like that until it sort of snapped out and luckily I didn't uh, snap anything at all. so it would have been nicer from a disassembly point of view to put screws in there.

But considering that, uh, you know you really don't have to open this thing. Um, then it's not really a problem. So here it is Taada and my first impression upon cracking this thing open is I'm actually, um, very, very impressed I Like it. It's got everything.

Well, it seems to be doing everything right. Uh, they really don't seem to have cut any. Corners at first glance at all, We've got the Uh shielding up here. We've got the spring terminal which connects to the shielding.

We've got the huge HRC fuses here, which we'll look at in a bit more detail. We've got uh I Love the goldplated battery. uh, contacts like that that I Love these battery contacts that don't use any wiring at all. They just use these uh, spring terminal Clips to actually, um, when they press down, they press onto the PCB I Love that that's what fluke are doing in their new fluke uh 28 and their uh Fluke 17 and other meters like that.

And really, the only bit of wiring they've got in it is going to the uh, piso buzzer up here. They've got a nice little connector on it. It's not just uh, dodgy solded onto the board like this. It looks like a real high quality connector.

There's a programming interface. they've actually used a connector for that, but we'll go into that when we look at the board in more detail. They've got a secondary board up here for the input connectors and they seem to be doing everything right. Although I can't see any input protection devices on the top.

uh, apart from this huge, uh, fusible resistor up here, that's like the low value 1K or less input fusible resistor. That's about all I can uh, see up there in terms of that. but we might have to, uh, flip the board open to see what's on the bottom. Um, but I'm impressed so far and they've done the case right.

It's got the um, it's got this extended part here which goes into the case to form some blast protection around the outside of the unit in case of, uh, gross overloads. It's it's not actually just a a press together case, but I expected even though it's not waterproof. Uh, given the O-ring on the battery compartment, I Expected there to be a full o-ring ring around the outside of it. But if you take a look here, it's not an O-ring It's like, um, tape.

It's like that, uh, plumbers tape like you use when you're um, doing up a, you know, a a a tap when you're actually doing plumbing and stuff like, like that, uh, Teflon sort of tape. So I guess that's the first time I've ever seen that. and and the tape goes all around the outside like that instead of an O-ring That's the first time I think I've ever seen that used in any product. Uh, maybe they've um, they didn't go because it's not actually waterproof.

They don't actually need an O-ring Maybe they've actually gone for just a Teflon tape. Maybe to because it is, uh, dust proof apparently I Still don't know what the IP rating is, but maybe they've done that to keep out the dust. but um, if they used an O-ring it wouldn't have uh worked unless um, there was some weird molding in there because you need a flat surface for O-rings and this bottom the case. It's flat all the way along.

but look, then it just curves down like that and goes around. So uh, and an O-ring um, seal really wouldn't have worked on that anyway, but they've used Teflon tape. find that rather unusual. But anyway, I don't mind it considering that's not a waterproof meter and there it is.

You can see some of that Teflon tape just sticking out of there like that. One of the first things I noticed that's different to most multimeter tear Downs is that there's not main I see on the bottom here. they've just got in. In fact, a quite an excessive uh number.

Not that that's a bad thing I guess, but an excessive number of discreet uh so packages and the and the passive components. They really haven't pushed the limits of the Um of the design so they're not using 0402 components. they're sticking to big nice so packages which are uh, cheap, available, easy to solder, easy to repair, um, and and likely give you a much higher uh, yield in production as well. If you compare it to, you know if you're trying to use some little BGA part or something.

uh, silly like that. So this almost is is if like it's an LCR meter in terms of uh, the number of uh, discrete devices. so it is a very discrete design. Uh, I presume the main processor is on the bottom here.

somewhere. here's presumably it's not label, but that will be like a J tag or an in circuit programming header. I would presume for the micro that's uh on the bottom and I would expect to see an off-the-shelf micro like an MSP 430 or something like that. We'll find out when we flip the board over, but uh yeah, it's There's just lots of passive circuitry.

The board is very clean. It seems like it's well laid out. Uh, there's no solder residue on it at all and I'll go into the individual comp components a bit later. There's a couple of Um surface mount electrolytic uh caps there.

There's a few components are missing and rather unusual. This thing is rather curious here. It's got like an exposed uh gold pad here with this large uh, large package capacitor here and another capacitor and it goes off to this rather unusual thing which, uh, it's almost like a sensor pad which goes off under the bottom, presumably goes under the board there somehow and it's connected in here and it's isolated and they've taken off the Uh solder mask and they've taken off the ground plane and and on the input uh side of the design, they've actually done a pretty good job. I Like it.

They got this secondary board up here which you don't see all that often. uh and the contacts are made with these uh brass uh standoffs here which go from the top of the board to the bottom. and because they are split uh, contact input Jacks I don't know if you can see in in there, maybe not, but they are actually split uh Jacks two-sided So they use that to detect which uh side of the uh where if a if a probe is actually plugged into it and because you don't need that on the voltage, you only need that on the amps. They've joined them together like that, but over here they are separate and they would actually tap uh those off to a sensor.

They go through and there's the two sense pins which go through to the board like that. but I I Rather like that. um, it seems very solid. It looks like there's um, some O-rings possibly around the input sockets as well, but considering that they've designed this to be sort of Splash and dust proof and things like that over the fluke 87.

Uh, that's that's something that you'd expect. They got the two big HRC fuses 440 mamp and 11 amp I Love it! They've got the high voltage isolation there with the extruded plastic uh coming through as well. There's a lot of thought gone into that I presume the input protection devices are around here and they're on the bottom side of the board. We'll find out that when we flip it open, but I like that.

I'm quite impressed. and if you look down there, it is actually a Rev4 board. So they've had a few goes of this. They have actually refined it.

It hasn't been out all that long, but they probably would have went through uh, three or four four refinements before they actually released it to production. And then the standoffs: uh, for the Uh serial Communications interface, you can actually buy a very cheap USB uh interface for it and uh, that just goes through hooks up to the bottom like that and that's just just your typical um Rs232 type uh isolated Optical interface. Let's go through the devices on the board here, shall we? I Won't show you all the parts up close cuz it's really hard to get a good image of the Uh chip number on the device. but I've taken a look at them and they must be big fans of Maxim They've used lots of Maxim Parts on here.

um I don't know. Maybe they got a bulk discount and uh, presumably no Supply problems because you can buy these meters, so go figure. Um, down here we've got a Max Uh 4611 which is a Uh Quad switch. There's quite a few.

There's one here, one here, uh one over here. there's one there and uh W what else have we got? We got a Max 4582 which is an 8way Marx Here, we've got another one here. We've got a 4,000 series um Seos device a 4053 here. Excellent.

Uh, got to have one of those on every meter I think I think it's compulsory pretty much. Um, there's a 74 couple of 74 HC series logic here a HC 132 here a HCT 74 Here there's another uh Maxim Max up here the 4583. there's another 4583 there and there's a Um 76 double O uh switch capacitor voltage inverter here and this is the ADC It's actually an SPI um TI part. It's the ads Uh 1242 and it's a 24-bit Um 4 channel ADC It's got a build-in programmable gain amp.

Uh, it's got 600 microwatt power consumption, which is necessary in a battery power device like this. 21 effective bits 50 and 60 HZ rejection Buil in so you don't need uh to actually select that in the software. It's got both um, both Main's frequencies built in so it rejects those. A lot of Uh meters on the market will actually have a menu option to select 50 or 60 htz.

Um, hum rejection. you don't actually need that need to do that on this meter. And there's a bur Brown Opa 340 here and down here it looks like I think it's a maximum um LM 285 1.2 volt voltage reference, but it's a pretty pretty crude uh voltage reference that one so it's obviously not used for the ADC Up here, the ADC has to have another um, um, another Precision uh voltage reference around it, but uh I can't really see one there. Maybe it's on the other side of the board and one of the other big things you'll notice missing.

Uh, well, from the top side of the board. anyway is the thick film Precision resistor Network We can't see it yet. it's got to be on the bottom there somewhere. And for the true conversion, there's a Bog standard ad 637 true RMS converter chip there.

no surprises in that. well that came apart uh, quite easily. There's a couple of Uh Clips here on the side which actually retain the board, three self-tapping screws, and there's the LCD module with the Uh zebra strips in there which actually connect through to the Border Sorry, it's only the top one there, as you can see the contacts on the board up there. and uh, it's pretty typical construction.

There's a few looks like they've individually, uh, barcoded the internal parts there. The range switch is fairly typical. um, they've got, you know, fairly good quality. Uh, sort of.

uh, brass contacts in there I Don't mind it at all. Look like fairly good quality played in on the board itself, but once again, there's not any significant current actually going through that. Um, it's just. um, it's it's really just a signal thing and they have actually labeled a bit of attention to detail there.

They've labeled the individual uh Channel positions like that I like it and it looks like I was way off. The Mark With this uh, shielding uh thing here, it's it's just an extra shield on the top which actually connects via this spring here. and um, really, it has nothing to do with, uh, this weird sort of uh pad configuration on the top that actually that actually connects through to a cap, a large cap on the top side of the board and I really like the design effort they've put into the backlight. Once again, they've eliminated the wiring with these two spring terminal interfaces here, which connect through to the backlight on the LCD and then when it presses against here, they just match up to the Ma contacts on the board.

Really good design practice. This really good attention to detail. Curiously, they've added a plastic spacer up here I'm not sure exactly of its uh function. Maybe it's a afterthought I don't know, or maybe it's purpose designed um into the unit itself I'm not quite sure.

No surprises at all. There's the thick film resistant network, but it does have a rather nice Shield over the top of it I Love it. and uh, there are multiple contacts in there. There's one at the end, uh there.

and there's multi. You can't really see it, but there's multiple ones in there cuz these thick film resistant networks set the range Precision because you got one voltage reference and then it gets divided uh down for the various ranges. So there's multiple Um laser trimmed Uh resistors on this hybrid Um substrate in there, and that, pretty much along with the Uh, along with the main voltage reference, determines the accuracy and the long-term stability of this. But they've gone a lot of trouble to uh Shield that, which is quite nice.

And there's the input Jacks I like them with the O-ring seal around the edge like that, uh, and the input circuitry. We can finally see that there's Uh, four Ptcs up here. no less than four, all individually heat shrunk. There's another input um, fusible resistor here, and that's lovely.

Nicely, heat shrunk there. I Lovely. It's it's. got the turrets in there.

it's not in, it's not solded directly into the board. it's in the. They've gone to the effort to put the PCB turrets in there, which help, uh, support the resistor. I Love it.

There's your 10 amp Uh current shunt that that would have been uh, tweaked to actually get the accuracy required. There's another couple of input power resistors over here and it's really I'm quite impressed. Adelin have really up their game on the input uh, input side of things I Really can't fault that at all. and it looks like are they a couple of gas discharge tubes as well? Brilliant! And the main processor is an NEC 78485 which is a 78k series uh, micro so not terribly unsurprising.

I guess some classic 74 HC 595 devices up here. Fantastic I Love it! I don't know what this does, it's an Atml H um 9362 it says. but really? I don't know I presume it's uh, the voltage reference I presume this is another voltage reference over here. but apart from that, there's uh, not much else on the bottom of the board.

There's a couple of diodes over here and that about does it. So overall, I'm very, very impressed with the layout of this board. uh, layout, component selection, choices. Soldering is first class.

there's no soldering residue the design I I Can't really, uh fault it at all. Um, probably the only thing which I said they could have, um, could have refined a bit more is not to have the uh flying lead here going over to the Piso buzzer cuz they're going to the effort to do the Uh battery and the backlight LCD and stuff like that with the Uh spring terminal. So I don't know why they didn't go the whole hog there, but apart from that, it's a beautifully designed meter and the LCD sort of hinges back into place with these nice little retention hooks on the end here so you just slide it in there like that and it's got some actual alignment tabs there and they go into little cutouts in the board and the LCD can't move. Nice design.

even with the lack of support for the PCB, it's only held in with a single screw down here. Once it's in these retaining hooks on either side, here, it is actually quite rigid inside there. I'm quite quite surprised. Um, they've really done well to get it like that I think it's by Design and not really by accident and there are the additional uh support uh posts here which would um, uh, help actually press the board and sandwich it inside the qu.

So to stop it, stop any vibration modes and um, things which are set up when you actually drop the thing or heaven forbid you do actually vibrate it during transport or something like that. Really seems like a nice solid design and it's back together. No screws left over. It's really nice and uh, tight.

I Love it. Let's turn it on and see if it works. It works. Beauty So there you have it and you probably don't need to guess my verdict.

it was pretty clear. I Thought this was a superbly designed and built meter. One of the best I've seen I Really like it. Hats off to Agilant, the design team there for doing this.

I Like it. It feels like it's designed properly, feels rugged solid. I Guess time will tell. Is it as good as construction quality as fluke? Well, it's I think it's pretty much on par.

but yeah, time will tell in terms of ruggedness, ruggedness, and product reliability. And stuff like that, It's a completely new design It you know it needs to prove itself. but really? I couldn't fold it. And if you like my videos, don't forget to subscribe to the YouTube channel.

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