Hi, What happens when you apply 5,000 volts across the range switch of a cheap ass multimeter? I'm glad you asked. That bit of fun and frivolity came from this puppy which is a Unity UT 513 insulation tester. maximum range 5,000 volt here also does Uh 2500, 1,000 and 500. really big bit of Kit I Thought we'd take it apart.

check out what's inside this puppy. Beautiful. Let's see if it does that at Uh 2500. yeah, still a little bit of arcing over there.

Oh, and it switched off. It looks like maybe the uh Ms or something uh kicked in or something kicked into, uh, overcurrent and this thing just switched off I don't know, haven't read the manual. Curiously though, this thing's fresh out of the box. It does weird stuff like this: I've like turned it, um, tried to turn it on again and like some of the segments come up, it's just really weird I don't know whether or not I've killed it I shouldn't be able to kill it based on just overloading something down here.

Clear e Stop there we go. Turned it off. Emergency stop Boom. Went back on but occasionally I found it does that.

Really kind of annoying. but anyway, that's a great deal of fun ,000 volts didn't switch off this time, but it, uh, just switched off the output. oh hello hello McFly McFly Come on, clear, maybe we got to clear something I don't know, this isn't going to be a review. Was supposed to be a tear down, but I thought I'd test a multimeter at this cheap ass V Vc99 heap of crap which doesn't work anyway and uh I applied 5,000 volts to the input I heard all this arcing and stuff like that and uh I thought I'd crack it open and uh, sure enough, the arcing was uh, the input range switch there but what's going on here? hopeless I don't know I've just literally taken this thing out of the box so I'm not sure what's uh going on there, but 5,000 volts across it is rather fun I never get tired of watching that I really don't there we go.

switched off. Now this isn't going to be a review, but uh, I'll just go over a couple of things anyway. $239 Australian dollars delivered uh from an eBay uh supplier here in Australia don't know about overseas prices. sorry haven't looked at it but uh, this is the UT 513 model it uh is there's three models in this range I think the first one goes to 1,000 volts.

Next goes up to 25 00. This is the top of the range which goes up to 5,000 volts. uh, quite rare to get that. um in one of these insulation resistance um, mega meters so to speak.

Mega is a brand name, but uh, that's the generic thing. Use comes in a okay a cardboard box and it comes in a rather Nifty little uh carry case here. no you know, excess room or anything like that I Rather like it. uh, it's got room for your probes.

comes with two very nice uh probes like this one's got a uh shield on it. Of course you've got an extra guard terminal on top. there's an earth so the black plugs into the Earth the uh, other one with the guard terminal plugs into there. and you've got a third guard terminal as well for noise shielding.

big uh, non removable. Yes, I'm not turning this thing on I should probably turn it off for safety. Shouldn't I e stop there? We go just in case I accidentally hit that um big crocodile Clips really like them? Um, but yeah, you can't take them out. Uh, you can't replace them with banana plugs on the end or anything like that.

Hence, while was just pluging a couple of these into the molder down there. and uh, it comes with a uh, linear power adapter. Look at that. 15 volts 1 amp.

Huge I don't even know why it needs 15 Vols of 1 amp. It's absolutely enormous I think it's spec at like 70 milliamps? uh, consumption or something like that. As you'll see, it takes eight C- size batteries. um, you know, but yeah, um, nice kit.

It's got a USB uh interface cable as well and it comes with the manual and software. It's a, you know, typical, uh, insallation resistant spec of like 3% or something like that. Nothing to write home about, but that's uh, more than you need for most um, insulation resistance purposes. So, but it goes up to 5,000 volts.

Beauty It's got a real basic interface down here. It's got IR mode no, that's not infrared, it's insulation resistance mode. It's got a basic uh, rudimentary DC volt mode and AC volt mode as well. No, not true.

Onis And the DC volt has got like a fixed um I think uh, 30 like a 600 Volt range or something. So you know you can't really use it as a multimeter and that's disappointing. Um, 600 volts. You think you'd be able to measure up to say 6,000 Volt range or something given that this thing can generate 5,000 volts, but no, unfortunately, it can't.

Um, so obviously it doesn't look like it's reading the output. uh, voltage at all. Um, it's just generating the output voltage and relying on the internal regulation to keep that in line. So that's a bit disappointing.

But anyway, there's an emergency stop button. clear button. It's got a USB button. don't know what the uh, the USB functions do yet? haven't used it, haven't really read the manual um, load and save um, some parameters or something, a uh comparison mode so that you can compare to a spec and a Time mode I don't know what the time button does and a big fat test button.

Um, and of course you can go up and down in the voltages in the LCD It's got a bar graph here, so if I turn it on, you'll notice that the bar graph goes up there. It should slowly creep its way up, but uh, we can disable that we can go up to. let's go up to 5,000 volts and generate and the button lights up. By the way, quite nice to tell you what's on.

And there you go. The bar graph is going to slowly go up and it's got a um 1 ter ohm uh well. full scale. uh, deflection up there.

So yes, just be aware of that. That is not a linear scale. um, by any stretch. Um, so because you know there's 100K down there, there's one Terra up there.

eh, that ain't linear and I think the barg has probably a bit of a wank visual feature here, because I don't think it has any faster updating than the digital display. But eh, looks good, right? It's Big And Chunky I Like it. It's a huge display. In fact, this whole thing is, uh, absolutely enormous.

Better turn it off here. Um, it's It's like it weighs like 2 and half. oh, 2 kilos or something. It's uh, it really is.

um, built like a brick. Obviously it's not. You know, it's got no creaking or anything like that. It is a, um, absolutely solid little beast.

I Like it. There you go: 1.75 kilos and it's got massively deep sockets down in there. Standard: Uh, 4 mm. looks like standard 4 mm.

B Banana Jack but they're all the way right down the bottom. and yes, look at that plugs in there and it's absolutely H Enormous port on the side here, which uh, flips open like that purely for protection. Um, it sits like neatly down in the bottom there. I Rather like that USB and the Uh 15v 1 amp Jack I Don't know know why it needs.

Well, actually, it probably needs one amp of course for Peak charging of the Um thing. Oh I didn't think of that. You know 70 milliamps as its average um consumption once the internal uh caps are charged up to the high voltage. but you know, um, so during a regular operation.

But when you're generating the high voltage stuff, yeah, you need that Peak current. hence the linear adapter with it. uh, linear, higher um. isolation voltage obviously.

And here's the back of it. Uh, Cat 3 600 volts, you know, whatever. Eight Csize batteries, you know, see Csize batteries that often these days. comes with golden Power alkaline.

Yeah, we export Ro chemicals in these things. You know, all the waste chemicals. Great. That's all we need.

Anyway, it looks like we have some really deep screws down in there I Assume that they oh that? Yeah, yeah. Phillips Yep, we have. Phillips So let's take it apart now. What? Um I expect to see in this thing of course is, uh, some well high voltage generator circuit, some output relays of course because um, you know.

Safety First high voltage relay. You have to, uh, you know, isolate the output. Of course, when you switch the thing off or press that emergency stop button, you, you know you want that relay to deenergized. So it's going to be a normally open, uh, one normally open.

Uh Reay So when you go normally closed, of course you know when you press the test button, it's normally closed. So there we go. Looks like we're about to come off. T Oh oh, look at this and some shielding.

as in high voltage. Look at that. Oh beautiful. This one's going.

hey, what's that down there? Don't know. Looks like it's just stuck there. but uh. anyway, that's what I expected.

look at. That should be quite safe. After I've turned this thing off, it will have, uh I assume it will have a bleed, um, uh, resistors in there. um to bleed off the charge.

but of course I will uh, be safety first and uh, actually measure, um, anything in there. So yeah, that's so. that's really quite nice. Look at this.

We have this whole isolation shield around this top board, high voltage generator board, and uh, that looks like our oh, looks like we got some cutouts in the board. We'll have a look at that. high voltage cutouts. We got high voltage cutouts around our relay down in here.

There we go. Now let's have a look at our USB input and uh, uh, DC jack first heavily recessed of course so that the user can't physically touch that and can't just plug in any uh power adapter into there. it has to be the one that comes with it. Raided.

got that long? um suitable Jack on it so you can't actually touch that because the wiring all in here goes back to the main board directly over there. so you want, uh, complete isolation there. And of course, um, as I said, that's why they're um, using the linear uh Transformer as well the linear plug pack in there. Now here's our USB chip.

It doesn't look like the regular ft Uh 232, so it's probably some sort of little micro. I'll have a look at that in a second. Um. and there's our USB and of course it is completely isolated.

Look, they got a high voltage isolation slot there, another one in there double whammy. So to get creepage across, uh, the board, it's got a snake its way all the way around there and Arc over to there so it's not going to go across the surface. So that's why they've put in those two slots. Nice.

They've designed that properly. And of course there's the infrared leak. They haven't relied on a uh, off the shelf opto coupler bugger that we can get to high voltage with just um discret Leads Here Much better. Brilliant.

I Like that, well done and I have no idea what that one is. It's a Wch CH 9325 so yeah, some form of uh USB to serial uh converter um I Googled it and all I got is a couple of references uh to yeah being used in Unity equipment. so go figure. You got any more data, post it and here's the main unit, which is going to be really quite.

uh, interesting. the high voltage uh section on the separate Board Of course there's our high voltage output relay. It's a Uh toward high voltage Reed relay lrl 10200 PCV it's probably like 10 Kilts or something like that I don't know based on the number, not sure but uh, you can see some the yellow caps in there. You can see lots of isolation slots.

We'll take this apart and we'll have a look, but uh, we got some celastic and uh o we got ourselves a thite there around our lead. They're just chopping a bit of the uh uh EMC taking the edge off. um any EMC there and that's coming back here via a heat shrunk. There we go via a heat shrunk resistor down into the main board.

So that is the that is the earth return line down there. and you notice the high voltage cutouts in there. They're almost like punch outs. Almost like it hasn't been routed.

Um, it's been punched or something like that. Oh no no. I Can see the routing marks. have to get in there with the macro lens and uh, check that out.

but of course all the digital stuff. Not terribly interested in that, but uh, we will have a look. couple of 10 turn trimmers in there which I won't touch. Not sure what that's doing.

What's the going there? Let's have a look at that puppy. Aha, there you go, It's it's the main micro of course. Um 8051 Um I am not sure of hand who that manufacturer is I'd have to look it up I don't know one of the generic uh Chinese 8051 uh suppliers. So yeah, that's the main brains behind this thing, which uh, would be driving the Um LCD as well.

that'd be a separate I mean it doesn't have LCD built in, so there's got to be another separate Um LCD driver there somewhere. there's you know, not enough segments, not enough pins on that thing to, uh, do it? But let's have another look. Ah CD 4094 some 4,000 series logic and what else have we got? 4052? 4,000 everywhere. Ah, and we got a 4011.

Ah, it's all happening all right. So the Tl494 Pwm controller down there is obviously controlling main Transformer Over there we have a couple of switching transistors and Bingo there's our main switching Transformer which will no doubt the secondary of that goes up to the high voltage board. Up there has a couple of uh uh, what you know, feedback lines there or something going on. So we're going to have to unscrew this uh cover and we have a um, another relay down here.

not actually sure what it's doing. with high voltage isolation slots under it, you can see it's uh, obviously doing something to um to do with that switching Transformer but uh, what exactly? cuz it's definitely not the output switching relay. that's what the big high voltage read relay is for. and that's what we expected.

But uh yeah, I don't know your guess is as good as mine. and these two guard terminals here just joined in series of course. uh, going over to here, just a guard terminal on the PCB Um, well, the top side of the bottom main PCB down there. So that's just the uh shielding for the measurement.

Uh, you know that would just be the shield point for the measurement star ground essentially for the measurement circuitry down on the main board there. so not like it's not like it's going to Main's Earth or anything like that cuz this is a purely isolated, uh, handheld instrument. and there's where that ground return wire connects down to the main board there via the his shrunk resistor. you can see the routing.

uh PA You can see where the drill has. Actually, if I can get in there, here we go. You can see where the little the routing drill has sort of gone into those corners down in there so just routed out those little isolation slots. Ender we' got some Analog Devices adg 858 don't know that off hand I believe just by looking at it.

uh, looks like a MX of some sort and 851 not sure what that is, have to look it up and a couple of miscellaneous uh devices over here. op07 Precision opamp of course with a trimmer attach to it. probably another yeah, another Precision Op amp over there next to the other trimmer. By the way, they got some more shielding tape on here and it it, um actually looks like uh, me, metal uh tape actually? um so yeah, it's um, they're obviously trying to kill the uh EMC on top of that uh chip.

that's why they whacked it on there. but you know I I don't know I mean you rarely see something like that. it's weird. and underneath the other uh Shield there we've got an MF Well, it's a LM 2674 DC to DC step down converter so you know it's like they like they didn't pass EMC compliance or something and they just, you know, gone around and whacked some tape on these things to to try and pass compliance and there's a third one down in there not even going to bother to take it off.

It'll be another little uh switching converter or something in this top cover plate here. We can just uh, lift that off and Tada we have access down into the main board which ah, it's been completely potted folks. you probably can't see it on this view, but you can see maybe the shine on there. but all of that stuff.

yeah, look. completely clear potting compound that looks like water in there. looks like a mini fish tank. There you go, check it out.

but that is a clear potting compound over the whole damn lot. They're really going to town down there. Awesome. So yeah, I can't even touch any of that if I try it.

Oh, it's the spongy. uh yeah, it's the. It looks like it's a re- enterable uh potting compound. I'll zoom in on that and uh, try and give it a little poke and uh, see if we can see that.

All right, let's get in there and give that a good little. see that there we go, there's our clear reenter re. it's probably oh no, it's maybe it's not the re-enter type it doesn't let's try and Pierce it with yeah yeah, it is the re-enter gel type. There we go.

I've just damaged it. it? No, it doesn't seem to like. um, heal actually. Uh, the re-enter potting uh compound is designed to.

You know you put like a screwdriver through, you can still adjust like a trimmer inside, or you can probe something and measure it. and then when you pull it out, it sort of self heals again. But uh no, this is just really soft potting compound. that's all.

I don't think it's the reent mble gel type, but yeah, really soft. I Love playing with this stuff and down in there we have ourselves a whopping 200 Meg high voltage resistor there. Not a problem that's obviously. uh, reading back cuz you can see it's coming.

the trace going over there coming from the output. Jack there it is Jack one. that's the high voltage output. You can see the Ferite bead on there just to knock some of the EMC off that they got celastic of course.

and uh, so they're tapping the output directly back. so they are actually doing some reading on there now. let's see if we can. uh, decipher the board here and I just looked up the data sheet for this high voltage read relay and I was right.

it is a 10 KT rated read relay. Uh, open contact 10 KT so 10 KT contact to contact. that's why it's that long. Um, and also uh, 10 KS contact to coil isolation as well.

but it can only switch. uh, 7500 volt. So yeah, perfect choice for this application for a 5 Kolt uh generator. They got some good margin on there so I really like it? Um yeah.

something you know. really obscure type part you um would have a hard time getting. but these obscure applications need these more obscure parts and it's got a 50 W contact rating as well. So quite a high power little beast.

Really like it. Wonder how much they cost in volume? Now if you have a look at the Uh Main High Voltage ball, we can actually see how this thing works. It's really quite obvious from the layout. Now here's our switchin Transformer down here: uh, primary, here, secondary here.

And yes, we are generating a high voltage on the secondary, but it's nowhere near the 5 Kilts that we require on the output of 5 kts maximum. So the Uh secondary of the Transformer is generating a relatively high voltage, but nothing near where we want goes over here. That's why they can get away with using these low voltage MOX type um, board-to-board intercon interconnect connectors that you're uh, used to using. They're not high voltage ones at all and that's why they're reading, um, stuff back here so that these two pins over here are your high voltage uh secondary from your Transformer and then we have a Villard cascaded voltage multiplier here.

Classic Arrangement Capacitor two DS Capacitor two D blah blah blah all the way over here. And here's our high voltage output here. and you can see the high voltage isolation slots there there and there's one on the under just on the bottom of the Transformer here. So this is our ultimate Uh 5 KS output here.

and of course they're tapping that off as I mentioned before: 200 Meg high voltage resistor down in there I don't actually know where that one's uh, going to I haven't actually followed that uh cable there and uh, done that one yet but that looks like it is actually tapping that back off and measuring that. but it's also tapping it off here and you can see where the high voltage snakes around. This is a high voltage divider with all these resistors in here and you can see that uh, they're just in series like this. so all these resistors in series isolated by that high voltage slot and it makes its way all the way over to here until the final tap on that voltage resistor divider.

quite low voltage. and then that's why how they can feed it back to the main board down there with that low voltage connector. So it's you know, it's pretty obvious when you look at it and um, basically exactly you know as I expected. Um, the the physical implementation is a lot uh, better than I expected with the you know, the separate module up here and fully uh, potted and all that sort of stuff with all the you know, even the uh, even a safety shield on top of there really is very nicely uh, designed and engineered.

They really knew what they were doing here. Now as for how one of these: Villard Cascade Voltage multipliers works I think I'll leave that to another video I've got an idea for that fundamentals Friday I think I'll have a go with it anyway. Um, so I'll go to the Whiteboard so I'll probably go shoot that now and I'll upload it. Uh, later on this week we'll jump very quick to a Dave CAD drawer in here of a Villard Cascade multiplier.

and as I said, I'll do a separate video on this in detail, but basically that primary over here, switch in secondary switch in of course and then we have a standard. Villard voltage doubler here and then that Smooths it out with this diod and capacitor Arrangement here. typical smoothing and then it does that again. Doubles Doubles Doubles all the way across until you get to the final high voltage output here.

That's all there is to it. Very common. It's the stock standard technique for generating high voltage. DC Now one of the things I found rather interesting is that the high voltage read whe sort of expected that to actually physically disable the Uh output connector up here, but it looks like they've got it on the high side.

I mean the terminal, the contact terminals. There's one here, one here, and then the coil is just two pins in the middle there, so it just looks like they, uh, just cut out the return for that rather than actually uh switching the direct output connector itself. I Just noticed these wires down in here seem to be a little bit pinched, so I'm not sure that's probably the Uh top case of this high voltage uh unit over here module over here, perhaps tension detail? It's important. and by the way, I did uh, lift this board up or attempt? do I leave it out about that far and I can just see under there.

um as I uh said, nothing interesting, just the membrane buttons directly on the back of this board. There's no second board in there and about under there somewhere there's a chip, just a little quad tiny quad flat pack driving the LCD so that's it. Nothing to see, nothing hidden, but uh, that is. It's just got a one big ground plane under there by the way, which uh, connects to the guard terminal over there and will ultimately be referenced back to the measurement part of the circuitry over here.

So that's all there is to it. but that is a really nice implementation. I uh I Am thoroughly impressed by that they've done uh unit, have uh, done their homework on that and done really well. I give that uh design and construction a big thumbs up I think I can't uh, really? F that at all.

It is rather nice so that was quite impressive and interesting. That's the unit UT 513 Professional Insulation Tester I wonder what their low-end ones are like cuz this is definitely is a professional Um designed and Uh built unit. I Rather like it I think they got a winner here and for 200, uh, well, under 240 bucks a stray and delivered I think it's a you know, quite good D Value: It's quite difficult to find uh, high voltage insulation resistance testers which go up to 5 KS actually that's why I uh got this one. It could come in handy maybe for uh testing overload input on some multimeters as well to see if they die so that' be really handy.

but uh yeah, you can get cheaper versions of this 2 and 1/2 Kilts I think and and a 1 Kilt version and I assume Yeah, they would just have a totally different Um multiplier board in here, so this one is of particular interest. It probably may not have been as interesting on the 22 Kilt one, but uh, if anyone actually does have the Lesser model of this, please, uh, post some photos. um post a link on the Forum or in the comments to your own photos online. CU It' be interesting to see the differences between say the bottom of the range 1 Kilt unit and this 5 Kolt unit.

Anyway, that is tear down Tuesday I have high voltage insulation tester. haven't had one of those before. Quite good if you like tear down Tuesday Please give it a big thumbs up. Not enough room on my camera here I Can't zoom out enough damn it.

But you know, thumbs up. And if you want to discuss it, E blog forum is the place to do it. Catch you next time.