Hi welcome to Tear Down! Tuesday Yes, it's vintage time again and yes, vintage test gear even better I Love vintage test gear and we've got classic analog multimeters today! I Got this one in the mail bag yesterday and I promised a tear down of it. It's a Uh Metrawatt Unig Gore A43 and it's just a beautiful unit. Look at that absolutely fantastic classic analog multimeter. But not only that, I thought I'd throw a few extras into the bargain as well.

We've got a classic Uh Simpson 260 Xlp. This one is, um, it's about a 1981 vintage I'm not sure about the Uh Unig Gore meter. We'll tear down this one as well and also the classic which I've done tear down photos of before but I've never done it on the video. This is my Uh Triplet 630 Na which I've had for donkey years and this is an absolute Beauty So we'll tear down these three, compare them, and see what the Uh construction's like across three different manufacturers of classic analog multimeters.

This is going to be fun, so you know what to say here on the E log. Don't turn it on, take it apart. So here they are side by side and aren't they just beautiful? Oh I Love classic analog multimeters. And as I said, I definitely know the Simpson Uh 260 Xlp.

The 260 model, by the way, comes in many different variations and there's a whole Uh website Simpson 260 dedicated to this meter and all the variations of it. So this is the Xlp. I've got both the Xlp and the Xlp. M here in the lab and uh, the triplet.

I'm not sure of, um, its age, but I believe you can still buy the 630 or some Uh variation of it still handmade in the USA Fantastic and metrawatt. Uh, Unior. Of course, metrawatt are part of Gossen now. Uh, so it's Gosen Metro they merged or something like that.

So I don't know about this I Had never seen or heard of this unior one before I Got it yesterday, but this one you can see the there's quite significant differences between the two. Now, the Unig Gore has a smaller Uh meter movement. These are quite large meter movements, but these ones are only 20 K ohms per volt meter movement and this one is a very high sensitivity 100K per Vol meter movement. So much more sensitive, higher input impedance which was a big deal back in the day.

Now the Metro What's pretty unique in that it actually measures capacitance. It's got a capacitance range I had an old Dick Smith multimeter which measured capacitance once, but that's the only other meter that I know of Analog meter that I know of that measures Uh measures capacitance as well. Now the Uh triplet over here. It's got a unique Uh feature of having Uh 6,000 volts, DC and 6000 volt AC ranges.

got separate Jacks over here. When we take that part, we'll see the big high voltage Uh input resistors in there to give those ranges. See it normally goes up to 1200 volts on the standard Jacks but over here 6,000 volts. Oh fantastic.

And this one also has a range doubler and this was a big deal back in the day because you can only fit so many things on a range switch like this. so you would have this range doubler switch. So Volts Ohms amps. So if you turn this around to 3 volts here, okay, yeah, it'll be 3 volts full scale, but if you switched the VA on two, then you would divide that figure by two.

so it would now be 1 and 1/2 volts full scale instead of 3 volts full scale. And the Simpsons's got a low power Ohms range and this was common on some of the very early digital Uh multimeters of the early uh, late 7s, early 80s and the low power Ohms. It's got lower Uh output voltage so it doesn't turn on PN Junctions in when you're measuring stuff in circuit. So that was a big deal back then and both the Metro and the Simpson have H cutouts on them.

Here we go: reset cutouts see triplet didn't have that. It was uh, famous for being able to handle like a thousand times overload or something like that. It was really rugged meter so didn't need any uh cutout protection or fusing or anything like that. And the triplet here.

Uh, It had a classic feature of the day which was called an output uh, terminal. but no, it's very confusing. It is not actually an output, it is an input. In fact, it's exactly the same as this except it's AC coupled so there'll be an AC coupling cap between that terminal and the Volts Ohms Amps input there.

So just to remove the DC component, but it was called output. So if you had to ask me feature-wise out of these meters, which one would I have I'd have to say my triplet 630 Na because it's got more ranges with that range doubling switch. It's got this unique high voltage uh input over here. Of course you'd have to have a specific High volage volage up probes.

It's got the output function and you know it, It is just a nicer meter. Overall, much more useful although the the unigo metrawatt has capacitance, but me and I really wouldn't pick the Simpson because not only is it the least accurate, but it also doesn't have a mirrored back like these two do here to eliminate parallx error when you look down on the the needle because if you look down at an angle then you can easily read the wrong value. And of course that was everything on these analog multimeters. So you know I I Think that's a fail right there on the Simpson 260.

but you know this has. This is probably one of the most famous analog multimeters of all time, the 260. But yeah, why it doesn't have that mirrored back in I don't know. Silly stuff.

But anyway, in terms of accuracy, the uh unior Metro has the highest accuracy spec at 1% on ohms and DC volts. The Simpson is uh, 2% um, and the triplet is is around about 1 1/2% and I think when we tear these suckers apart, we're going to find fairly significant differences in the construction quality. Let's have a look now. Just as a little bonus here: I'm going to show you a way that we can get these meter movements to move without actually applying any input signal or physically like shaking the Uh meters or anything like that.

Watch this. Woohoo! Look at that. triplets. Not that.

yeah, we can get the triplet going and we can get the unior going and we can sort of reset those back to zero just by putting my hand on top like that. There we go. Look at that. Love it! So that's just a little trap for young players there using analog multimeters.

Beware. So first up, let's open this: German Unior A43 from Metrawatt and I do not know what's inside this I've never opened it and I've never seen photos so I guess we'll find out. Um, there's the back panel of course comes off here which I showed in the previous video that allows you to replace the battery and the Fus is in the thing. But let's take these screws out and uh, see, somebody's had to go at this one.

um It Wasn't Me By the way, this one had metal threaded uh screws, presumably into some sort of uh, metal brass inserts or something like that. So let's crack this sucker open and see what our German quality is like to. oh oh, that folks. um, is not not impressive at all.

that looks really crusty. Oh my goodness, that is just I I Won't say awful, but jeez, that's you know. I I Wouldn't blame anyone for calling that pretty awful. Um um yeah, actually yeah, that's yeah.

it's pretty awful. We got something like a you know, folic base board or something like, or you know, something like that. it's not, doesn't look to be a particularly high quality uh board here and really look at the the tracers are they like just tin plated and well, they're just all starting to corrode and all sorts of things. I Don't know the age of this one so I'll be fair, you know we it.

it could be like, you know, early '70s or something like that, so not terribly surprising with hindsight I guess but the rain switch does not look terrific at all. You'd have to get in there and take a look at the contact, but this meter measured spot on as I saw in the Um showed in the previous mail bag. There's the there's the contact wiper coming around there I might show that in a bit more detail in a second. We've got a huge current shunt here.

You can see the uh pattern uh, well, you can't see it, but you can presume that there's that uh, zigzag uh pattern that wavy pattern in there to get a certain resistance. and they've done that a couple of times here. There's some more current shunts up under there as well. So yeah, but oh, it's just the wiring and everything else.

The Doo just solded directly on here. I'm going to presume that they're uh, because they're backto back like that. They must be the meter protection diodes. and in these multimeters, these are going to be a Geranium uh type diode.

because they want the absolute lowest forward voltage drop across there. they put them back to back to prevent uh overloading of the meter movement. cu The things that blow in these analog meters, of course are the meter movements themselves. So of course, if you apply an overload in here M Analog multim.

they just basically series resistors and everything else. So if you choose the wrong r range I Mean you know if you go right down to the 30 micro range or you know, um, one of the low voltage ranges, then really, that meter movement is at the mercy of the inputs there. and the only thing that's going to save it is clamping the voltage, physically clamping the voltage across the meter movement. So regardless of the input polarity, they'll have two backto back.

uh, those will be Geranium I Can see a part number should be able to get that. Hang on? Well, no. I'm surprised these aren't a Germanian type. it's just just a standard 1 in 541.

So just your standard uh, 3 amp silicon Dio back to back there. So um, I think Well, Well, I'm rather surprised by that. I Think we might find Geranium types in either of the other two multimeters. So yeah, that's not terrific.

Now this is rather interesting. Check this out. Right next to the fuse holder here, we have what looks for all the world like a spark gap. Just a tiny little gap between these two sides here.

so that's what that must be. Well, I am particularly impressed that they do have uh, metal shielding inside the back of the case here. That's rather nice. And then they've got this spring clamp here which just, uh, makes contact with the foil down there.

and I really don't like the way this is all assembled. these plastic Clips here hold these boards in, but then that is going to uh, you know, affect the range switches that they're kind of rain. switches seem to individually clamped onto those boards, but it just seems all a bit how you're doing with these wires. then join Bridging the boards together and I don't Oh, it's just no, it doesn't instill a lot of confidence in me.

I'm not impressed at all. Now it's rather interesting how they implement this ganged switch. Arrangement Check that out. They've just got like a like a pivot arm there which then just moves that switch back and forth the contacts on the board.

It's actually, it's kind of clever actually. Um, but yeah I don't know how reliable it is is, but jeez, I don't know. It's kind of fun. now.

one of the most interesting Parts about this thing is this overload. uh, latching Reay circuit here. As you can see, it takes up a fair bit of this thing. Now here's the input jack over here.

so the input jack goes through an input fuse here and part of the spark gap there, but then that runs all the way across there to this contact. over here. Inside there, there's one of the contacts. Now here's the reset button on the front and the other contact coming out here.

So this is just like the the Reay contacts and then that just latches in place like that as you can see when you reset it and then once the thing triggers over here due to an overload, senses that it just goes Wham and disconnects your input signal. and then you have to physically mechanically reset that sucker. so that's you know it's It's rather neat how they've implemented that, but yeah, it does take up a lot of space and it's a lot of effort to go to just to protect the Uh meter movement essentially. And you can see that on the schematic here.

Here's our input terminal, positive input terminal. there's our input switch, there's our spark gap, and then here's our relay contact here. this latching relay contact and this is the Uh coil side used to actually trigger that and then that just disconnects anything. the input signal going down to all of the range switching all the way down here.

But as we'll probably see in the triplet one, it doesn't have any of this overload protection. Now I Think we'll find that the triplet will have really good quality Geranium low loss geranium diodes across this meter movement here. back to back, there's the two back toback diodes. uh, and we'll we'll think we'll find that will be adequate to actually protect this thing from from protect the triplet from overloads.

but uh, this one, the metrawatt and I think and the Simpson has a Uh reset circuit as well. so we'll find those are cutout circuits in those two but not in the triplets. And what else have we got in here? Well, we' got some. You know there's a big ass carbon uh trimmer in there.

There's a couple of more carbon trimmers right down in there. I could really get inside this thing, but I'd have to take it all apart I'd have to desolder all the connections and I don't really want to do that. See, we can see the more current shunts in there. You can see some of the components on the top side board.

There, we've got uh, a plastic, uh DC series transistor up in there. Um, looks like we've got a dipped uh tanum up in there. Some uh, classic C, um, ceramic caps. There got some really high value resistors in here.

There's a 3419 Meg 2% resistor There some really high value stuff. As we come around, we can see the Precision resistors here. These are 0.5% Not bad, that's you know. 2 Meg 1, 2.16 Meg Of course, these analog meter movements they had to use.

uh, precisely calculated resistors. They're not just going to use the regular, you know, E12 or E96 series or whatever. These will be like obscure values specifically calculated for the range dividers required for the various ranges. So those Precision resistors look pretty good.

I'm fairly happy with those. And uh, there we go. We got a big ass 4 wat power resistor over here. We've got ourselves a neon lamp and I Do recall from the schematic that there were at least a couple of neon lamps in there just for some, uh, overload protection there.

And uh, well, there's not a huge amount more interest in inside this sucker. We got ourselves some big wire round resistors in there other ones, so they must be for the various current ranges. So there you have it. there is the German Metrawatt analog multimeter and well, I can't say I'm impressed at all.

I'm sure it was a really good meter for its day, but it has not survived the test of time very well at all. It's pretty crusty all right. Let's check out the others. Next up, the Simpson 260 XL 6 Xlp overload protected so it'll be interesting to see what sort of uh, reset circuit they got in there.

If it was complicated as the one inside the metro. and there's inside the battery compartment of this thing, you know it doesn't instill a lot of confidence in you. Up front, we got a crusty 9V battery snap there and another D Cel uh holder in there. just a 3 AG uh glass fuse.

Let's check out the rest of it. All right? let's lift it up and see what we get in here. Oh look at that. It's a bit neater laid out.

of course, a single board. Is it a bit neater laid out? big HRC fuse? Look at that. Huge thumbs up for that. That is absolutely awwesome.

Um, massive HRC fuse? Yeah, the board is. doesn't look impressive by today's standards. You know the uh, Fr4 standard boards and you know the really high quality fiberglass you can get these days. It's got that sort of.

you know that Bake Light uh phenolic base type feel to it, but that one is reasonably well laid out. We got a a couple of bodgers you know, the resistors straight across here, but that was fairly, uh, common in the day, but that is quite neatly laid out. Not super high quality, but I you know that is at least instills a lot more confidence in you than the German uh Metro one, that's for sure. Oh, by the way, I missed that the Uh Simpson actually had the output uh function as well.

and if we flip it over, you'll see there's our input coupl. There's our AC coupling capacitor. There's the output terminal there, and just AC coupling capacitor right over to the regular volts. Ohms Jack over here.

that's it. Just AC coupling. One interesting thing to note: look, they've molded in like a tie down Point here and that's all that is. There's nothing on the front for that, it's just a plastic standof as part of the case with a screw and then a couple of terminals in there just to allow you to mount that 7.5 Meg resistor.

sort of. you know, free. hang it in the air like that and then tap off there and then have the other resistor coming around over to this terminal here so they put a bit of thought into that. Don't mind that at all.

I Mean, there's nothing wrong with good old point-to-point construction like that eliminate in the board. We'll see more of that in the Uh triplet in the next. uh, tear down. But let's have a look at the rain switch.

There's our switch contact and that's not bad at all. There's uh, it's dual sided wipe they've got there so well at least on some of them are. Yeah, no, all of them are dual-sided wipe. You can get right down in there and have a look at that one down in there.

You can see it wiping on both sides of that contact there so that that is not bad at all. Of course it's a multi- level switch as most of these uh multimeters are can't really show you that down in there and you can see how. there's like some unused slots in here. And this is for all the different model multimeters they will make.

They'll have basically the same physical construction switch, but then they'll just, uh, manually put in the contacts they need for a Spe specific Uh model with a specific Uh set of ranges and functions and things like that and these are rather hilarious sort of looking. handmade hand wound, hand heat shrunk, uh, shunt resistors in there for the current ranges. That's really interesting. Here's another one that's uh, popped in there.

Check that out. Classic and well. these trimmers give me a lot more confidence than the ones in the Uh German unit. Yeah, they got.

You know, they probably like a similar, just a carbon backed, you know, wiper, but they just instill a lot more confidence in you. and they just look better quality, not as crusty and these suckers here look for all the world. Like Geranium Dodes. There we go.

Um, here's the two meter terminals here. So we're going to have back-to-back diodes across there. but I'm not sure exactly which ones they are though. and yet, sure enough, those are all 1 in100 Geranium Dodes there.

So you know decent quality, low loss diodes that you can really clamp that meter down with. And that's about the worst looking, sort of, uh, corrosion type thing on the back trace of those of those boards. So this one has fared fairly well. I Mean we're talking uh, you know, 3 3 34 years old multimeter here, so you know, over well, over 30 years old and it's still in pretty good.

Nick Inside I Like it there. One thing I do do like in this battery, uh compartment though. Nice little spring on there to hold your 9V battery in there actually retain it and then over here. look, we've got a duplicate cutout space where you can put a spare 9volt battery in.

Nice thinking. Now one thing you really got to watch out for when you mount these end on uh, axial resistors like this is. look. these two were actually physically touching.

And yeah, they're probably almost certainly going down to the same solder joint. but you know, so it doesn't really matter. These ones over here, they're practically touching. They're a fairway apart, so they might may not be the same.

Uh, you know, node? they may not be tied together. You just got to be careful when you actually, uh, you know, manufacture ones like this, you don't want to short stuff out. I Mean you know they've got leads just hanging out over here on these dodes, you know, Not terrific and really the best tolerance resistors I can find in here are only 1% but uh, you know that's adequate for the 2% uh, total spec of this thing. and it's also you know, probably trimmed to within range and stuff like that.

But yeah, you know, not as high a quality as uh we'll find in the other two in terms of uh Precision resistors. but I do much prefer this just single board design to that. uh German One look and here's the you know they got the nice ball bearing right down in there. You can see it on the for the range switch and then it.

It just comes up on the top and it's all done on the top. It's all EX accessible and everything. It just really is quite nice. Nice big beefy uh tabs here on the terminals and yeah, it just is a nice cleaner um simpler design than what we get in the Gosen.

Well, the Metro um one. sorry keep calling them Gosson. Oh goodness. Anyway, here's our reset circuit and it looks like we got exactly the same thing going on here as well.

We got this big beefy wire coming down here, over to one of the contacts and then this other beefy wire over. so we got ourselves a big beefy Reay contact there and I can trigger that. There we go and we can now see the gap between there and if I push my finger on the bottom of that, we can see it reset. So that is just a much uh, simpler and more compact Arrangement than what's used on the Metro wat I Don't mind that one.

So when you look at everything as a whole in this Simpson 260 you can uh, you know, see that this one really is quite a winner. You know the big HRC use the meter tied directly into there, the single Ball construction easily uh, accessible, the uh, decent dual contact waer switches on there, and you know just the uh, attention to detail in terms of uh, the pointto point wiring and stuff like that, and the reset uh circuit that is implemented quite well I Can see why This is a classic multimeter all right. Now for my favorite: the Triplet 630 Na. Love this analog meter.

Let's let's whip it apart and uh, the only thing I'm not too keen on on this one is the input Jacks Pretty much and you can see why here. they they got the split in them. They're not a solid input jack and they're just, you know, press fitted into the Plastics surround there. not that great and you know they just tend to be not nearly as reliable as the more the solid machined input jacks on the other meters.

And here we go. You have to take the back off to replace the Uh battery on this thing. and Tada Look at that. Isn't that a thing of beauty? Look at that.

It's practically a work of art. Oh, it's just gorgeous. Wow, That is a real Bobby Dazzler. Look at that.

I Mean there's no PCB in this thing. It is all handwired directly onto the rain switch here with all the individual Precision resistors all the way around that thing and everything's just free wire wired in there cuz there's no complexity in this's. no added complexity in this thing at all. It's just beautiful and simplistic.

I Love it! Now let's start out here. There's our output terminal with our AC coupling cap there. and then we've got our huge high voltage resistor for our 6 kilovolt range. You can see the 6 kilovolt terminals are all the way over here, completely isolated from everything else.

So we got two resistors there. There's a big Uh 2.4 Meg 1% resistor and this one's a 24 Meg 1% resistor. Massive. This is why it can measure 6.

K Fantastic! And then we've got our range doubler switch here. You can see the little ball bearing down in there on this thing. Nice attention to detail with the ball bearing latch there Beautiful. but of course that's not actually a terminal.

The uh, actual switching mechanism is down on the bottom plate of this. uh, whole switch mechanism here and just the ohms adjust here on it own. I Mean you know it's design problem. It's got its own mounting plate and you know, standoffs and everything else and then just free wired in there I Love that.

Beautiful! Then we've got ourselves this high quality trimmer resistor here, mounted as a standoff there from the switch mechanism. and then, yeah. It's a bit disappointing that the top part of it is just, uh, solded to a component lead there. But yeah, that's a real that looks like a real high quality uh trimmer there for sure.

And then on the meter movement. here, there's another trimmer just in series with the meter movement. We' got ourselves a high voltage cap on there, but you'll notice that there is no, uh, back-to-back protection diodes on there. Where are those Geranium diodes? This one definitely does have geranium diode protection.

It must be built into the meter movement itself. Um, because it is. No, there are a couple of other diodes in here which I'll show you in a minute, but they are not the meter protection diodes. Now, the best part about this meter is that you can pretty much just abuse it and not worry about blowing fuses or blowing your meter movement or anything like that claims in the data sheet that it's capable of a thousand times overload on the meter movement without any fail.

Yes, it does have a fuse in here, but this is just a fuse for the battery protection. Uh, down in here. So um, that's got nothing to do with like the 10 amp input range or any of the other ranges at all. So there's no reset circuitry and there's no input protection fusing at all.

It just doesn't need it. It's built like a brick. dunny. Now the batteries on this thing are worth taking a not out.

There's a big Dell of course and there is a ever ready 413 battery. Look at that bet, you haven't seen one of those in a long time. 30 volt battery. Let's measure that and see if it's still good.

Union Carbide Ever ready I Love it! Ah classic. That's probably the original and of course it would be sacr to measure this battery with anything else but its own meter because analog multimeters don't need a battery to actually work of course. So this is a 30 volt nominal battery. Let's hook it up.

I'm on the 60 Volt range here. 60 volts DC range. There it is. and yes this meter is within spec.

It's my own meter. I uh do I have checked it and it is Boom look at that around about 27 volts dropping a bit. That's probably the set the input resistance of the of the Uh meter draining it a bit. So yeah, it's on its way out that battery.

but hey, it still has charge. Awesome! And have a look at the 10 amp current shunt here. Nice big, you know, Nichrome wire going right across there, tapped, trimmed with the correct tongue angle right at the correct. Point goes all the way over to here and has its own little holder molded into the Uh case over here where they can just tap off those with the wires required.

nice. And at the end of that current shum there you'll notice the green sense wire coming off like that. So they they're you know, tapping them right off at the precise points that they need to and they've trimmed that and it's just. it's nice attention to detail.

But look up here at all these gorgeous resistors. Oh and I Just love this custom molded plastic resistor holder at the top. Each resistor got its own little spacer in there with walls in between and all of these are Precision Very low aging resistors. Awesome.

Half a% on all of them, even the high value stuff. So really terrific quality and that's why they're able to get the accuracy on this thing. And if you're wondering where the uh, rest of the stuff is for, like the AC the rectifier, well look at this can. We got some wires going in here, got a shielded can if we pop that off.

Tada We got ourselves some Jama couple of geranium diodes in there and a couple of caps and uh, that's for our AC rectifier that is not for our meter movement. uh, meter movement protection at all. That's for the Ac voltage range, but very nicer than the shield that that's just lovely and you can just see down in there the ball bearing movement. And I'll change this range switch and this is really one of the best range switches I've ever felt.

It's just fantastic. Rip Snort Now Triplet do still manufacture the 630, but it's not nearly the same as this classic one. It's only got like it doesn't have the range doubler it doesn't have. You know, it's only got 25 ranges.

doesn't have the high voltage, any of the fancy stuff that this puppy has, but hey, they still manufacture the 630 I Don't know whether what it's like inside, whether or not it's still classic point-to-point construction like that. So there you go: I Declare the Triplet 630 Na the winner. How could it not be? Look at that. it's a work of art.

Bobby Desler So I hope you enjoyed that classic analog multimeter shootout. Tear down I Guess it is. Uh, three classic analog multimeters two made in the USA one made in Germany I Reckon the Triplet 630 Na is the best out of those Bunch there. But hey, the classic Simpson 260 or probably very popular in Europe but pretty much probably unknown.

Uh, outside of there the Metro Unig Gore a43 Which one do you think's best? Leave it in the comments or if you've got a better, more classic multimer, share some tear down photos with us. The link to the EV blog Forum down below where you can post and discuss this stuff. and as always, if you like Tday on Tuesday, please give it a big thumbs up or two thumbs up. but you can't do that on YouTube Eh, catch you next time.