Hi welcome to Tear down Tuesday Yes, it's another multimeter, but it's not a new one. it's an old one. Well, it's a new model. You can still get it.

It's the Keithley 20115 THD multimeter 6 and 1/2 digits. classic old green vacuum uh fluorescent display. There probably looks a bit washed out on the screen here. I Think that could be the uh, just the uh color balance or something on the camera here.

at least on my screen anyway I Scored this puppy on eBay uh for around 400 bucks. Absolute bargain. as I said, still a current model, you know, very precise. I forget the exact Uh specs off the top of my head, but uh, check it out.

Compared to my Uh EDC reference standard here and it is bang on of course. and I can just dial that sucker up. look at that goes up. it's of course 6 and a half digits.

this one only that gives six decimal places. This one here only gives my calibrator only gives five decimal small places. but yeah, I can just uh, turn that one up. No problems at all.

so it's bang on. but I thought we'd uh, take a look at this. it is uh, it was designed in uh and first sold around 1998 or thereabouts. so you know it's around about a 15year old model.

thought we crack it open have a look. Now the interesting thing. this isn't just a multimeter, it's a rather unusual Beast This THD here of course stands for you guessed it, Total Harmonic Distortion and it's able to Do complete THD automated system measurements Uh, when you hook it up to a PC I haven't actually uh tried that yet of course to actually see it and that means it does have a low noise function generator or audio frequency range function generator built in and as we'll see on the back, uh, it's not on the front, but the back has the Uh BNC output connectors for the low Distortion function generator. so it is quite unusual so it could be a bit interesting inside.

Let's check it out. Everyone loves a good Precision multimeter here on the Eev blog. all the offici andad they're getting a bit moist right about now. The thing with this instrument though, if you can pick it up for this sort of price, it really is a bargain.

Uh, but it's not. Uh doesn't have a massive Uh range of functionality. Take for example, the Uh current measurement. here.

it's um, well, Amps DC It's only got million amps and amps ranges basically. and you can Auto Range that. So it's got uh, there it is. 3 amps.

It only goes up to 3 amps maximum. Okay, it's got 1 amp, 100 milliamps, 10 milliamps. but that's it. Doesn't have microamps at all.

Real bummer, but oh well, you can't have everything. does support of course. Uh, four wire Ohms measurement. with the four terminals, there probably shouldn't be feeding voltage into that during the Ohms range, but uh yeah, it's you.

Know it's designed specifically for for um, this automated system measurement kind of. Market You can select the Uh number. Let's go back here. We can select the number of digits of course.

Very fast updating, super quick and we can set our update rate as well. Slow. that was on medium so now it's saying slow. We got fast.

Look at that. I mean that's ridiculously quick I'm not sure the exact specs of the update rate, but uh, it is very quick indeed. It's got filter in and it's got um, oh yeah, we can filter 10 readings and actually we'll be able to see that. enter moving average.

What types of filter? Oh there we go. We got repeat moving average. So let's turn the moving average on all right. I've dialed 100 uh, moving averages in there and if we tweak that up boom, we can see that I just jumped to 2 volts and it takes a while to get there because of that moving average And of course it's got the source built in.

I Haven't actually tried any of this yet, but uh, sign out I'm not even sure. um Channel 2 You can set the amplitude, set the impedance, set the frequency I Believe the frequency is under like audio measurement uh type range it might I don't know, go up to 50 or 100K or something like that. but uh, it does have and then measurement capability THD units you can. oh you can set upper harmonics, frequency, all that sort of jazz and it's controlled via Gpib or RS 232 is you can get uh uh, step and scan and all sorts of that system.

multimeter uh capability as well. So really is quite a versatile instrument. but uh I'm quite interested in the automated uh, you know frequency uh THD part of it and getting uh frequency, uh responses for um, audio, uh, frequency range systems so could be quite interesting I'm going to have to probably do another video hooking that up to the Uh PC this will just be a tear down down. Does Thermocouples does Diode continuity? I Don't even know what speed the continuity tester is.

Now let's give that continuity tester a go. You can actually set the level of the the the value there so that's pretty darn quick. Actually pretty impressed with that continuity tester now. I've got to say this is one of the dickest tilting Bales I've ever encountered.

Is it a real dog? It's oh man, whoever designed that should be shot now I Don't see any uh, build date or anything like that on here. There's a Seral I'm not sure if you can correlate that on the Keithly website, but there it is made in the US of A and here it is uh Source output. It's also got an an inverse Um Source output and looks like a Uh P some sort of pulse output as well. rear terminal uh multimeter input: there's a switch on the front as you probably saw uh to enable you to switch between front and rear panels as is very common on these bench multimeters, a trigger link interface, some sort of custom thing Rs232 um, almost certainly not isolated would be my guess and I E48 SL Gpib and if you have you look at the Uh voltage selection and fuse here, you can see it's got uh, might be able to see in there 240 there it is and it's actually got Uh pins on here.

There's a couple of pins there and a couple of pins there and depending on um, oh sorry, you can, just how do you? Yeah, you pull that out and you rotate that into position to uh, select your Um voltage and then there there's the there's the labels on the back of it and then you just rotate that around and these pins, um, go into the socket there and select your voltage. Quite novel. I Like it and it looks like we just got standard. Fair Here the two screws at the back, this panel, um this back uh feet thing will come off and uh, hopefully the top.

well the whole thing should uh slide off. So that's the plan and this is 15y old technology keithly I'd expect lots of uh through hole stuff. It'd be interesting to see what uh reference it uses as well. I'm sure the all the ah there we go shouldn't have screwed that out too far.

Sure all the multimedia Fici, andad are just waiting to see what the reference sensor in this puppy is. and uh yeah, we should probably have to get a couple of no H Yeah, there we go. Couple of little Philips on the bottom there and uh sorry about that poor camera ship. Is that the word I Need a camera operator? Full-time camera operator? That's what I need on the on screen Talent Yeah right.

All right, that that now should hopefully slide out somehow. Yep, there we go, Taada, Let's have a look inside this puppy. All right. hey, two two Transformers in there.

That's a bit surprising. didn't really expect that. And there we go. I See a motor roller processor there? Let's have a quick first look at this thing and we have a Motorola 68306 Fc16 processor there.

obviously got our system ROMs Here we'll have a look at it in a bit more detail. Aha Linear Technology is that the reference? we'll take a good look at that. We have a shield here, which, uh, you know, um, looks like it's covering some real Lays. We'll have a look under there, so that's probably some of the ADC integration, um, circuitry or something like that.

We'll have a look, but uh, it's rather interesting. There's a second board down the bottom, which is clearly the uh um, you can see it? Well, we'll see it down there. It's connected directly to the output terminal, so that second board down the bottom uh looks to be the function Gen board and the top one I Believe that's the reference there. So the top one uh is probably the ADC part of it.

so let's take a closer look. All right, let's start with our input circuitry. down around here, you can see the big switch coming from the front panel there on the left, big lever coming in that's a multi-way uh switch to switch the four wires coming in from this side front panel and the four wires coming in from the rear. That's a, um, very common way to do it.

You do it on the board there, just the wires coming straight in. We've got our input circuitry around here. There's a big ass verer if there ever was one big gas discharge tube, big input, uh protection resistor by the looks of it. Um, two big.

they're twoo big trans. Well, they're labeled Q so they're probably transistors. haven't looked at the Uh numbers on those and uh, we've got our high voltage resistor here. It looks like it.

Well, it looks like it's a four no. Could be a no a six terminal device, but it looks. it's interesting. I'm going to get a closeup of this cuz it's like almost like three different ones sandwiched like glued together.

There's one on the top here, one in the middle and a smaller one on this bottom side. so let me have a look at that. But there we have some sort of opto coupler action there happening. We've got a isolation slot.

We' got high voltage isolation slots around here. We've got big Power SMD resistors here. A lot of those would be in series to give you, uh, high voltage once again. and uh, we got a Reay switch in.

There's some more high voltage isolation slots there over this side, between the crystal separating that that looks like a diode bridge and what's that puppy? Let's have a look. You can see those uh Precision film resistors down there on their ceramic base. It looks like they're all glued together, presumably to, uh, just thermally Bond them all together. There's actually three of them and they're a Kadok TF series.

Let's go to the data sheet. There we go: TF Ultra Precision film resistors low temperature coefficient uh 5 PPM per degree c Yeah, pretty darn low from 1K to uh 25 megga .01% tolerance. Not too shabby at all. Maybe they're even uh selected or they could even get a better grade I Don't know.

You'd have to go into the uh uh, because you can often um, custom ordered these resistors. So yeah, there they are. They're just single like that, so maybe they're uh, there's a reason to thermally uh Bond them together. they're uh, obviously you know, not individual range resistors if they were I you know, I don't see the uh, uh, the reason for that Anyway, very precise resistors.

probably cost quite a bit. So yeah, they haven't skimped there at all. And here's the block diagram for the analog input circuitry. This is in the service manual for this thing and I will link it in down below.

So if you want to check out the service manual, unfortunately, it doesn't have itics, but it's a chalk full of all sorts of goodness if you actually own one. In terms of you know, calibration and uh, stuff like that, it's got a um, a scanner option. Uh, of course, this one doesn't isn't fitted with a scanner option. In fact, I don't see anywhere to put a scanner option, um, physically in the thing in terms of uh, you know, a cutout on the back panel or whatever.

So anyway, fairly basic. uh, multimeter. You know, analog input circuitry. It's got a marks with gains ADC u65 There haven't found the ADC yet.

doesn't mention the Uh reference on there at all. So I'm going to have to search around. and there is the ADC u65 and it's got, um, it looks like a custom device. It could be off the shelf and just uh, rebranded.

Um, of course, but it's got 2000- uh, 80, 80, Z Ao2 so might have to look that one up. But 2000 may not be a coincidence because look, this board is shared between the Keithly 2000 and the 20115 model which we have here. and I just looked at the parts list for that and it lists it as a programmed ROM So there you go. It could very well be a custom ADC that you know Keithly developed a long time ago and uh, just like Fluke, you know, developed their custom Adcs a long time ago and they're still using them And there's our refer there.

And yeah, it has a linear technology. uh, part number on it. Oh, there's a little. is it wobbly? Nothing worse than a wobbly voltage reference.

It's like it's just got a Uh cap on that. but uh, I Checked the Um parts list for this. It's actually an LM 399 Yes, Manufactured a Second Source by Linear Technology. Now if you have a look at the Uh circuit, overall, you can see the isolation slots in here dividing the digital section and these opto couplers.

Looks like some of the digital Uh processor section over here is coupled through to the uh, uh, the output side of the trigger uh circuitry down here. That's the trigger connector down there. So it looks like um, the Rs232 which is here. Of course.

here's the Rs232 drivers that will be uh, isolated from your ADC input so you can, uh, safely hook it up I Believe, safely hook it up to your PC and uh, do the business there. And if and there we go, there's more isolation slots around there, that's you know. Probably why they're using a couple of Transformers uh in here. Actually, they're powering various things.

This one pops over here and looks like it. Powers the digital circuitry. there. We got another one coming in there powering something probably.

It looks like the display section up the top has its own little power supply perhaps? Um, so that's rather interesting. and the probably the second Transformers is probably powering the board underneath so everything's isolated from everything else. Curiously though, the Transformer there very very close to our input sockets. Check that out.

Our input wirings, just, you know, flapping in the breeze there. I Love these little uh retention. uh Clips You know theyve gone to a bit of trouble. Obviously, they don't need to Shield these.

Um, so you got to think that Keith Le know what they're doing there having the input uh wiring so close to the Main's Transformer Like that. and of course they would I mean this thing's probably got, um, excellent. uh. supply line rejection anyway in the ADC front end.

So there we go. There's a voltage reference. lots of uh Analog Devices uh Precision opamps all around there. As you'd expect, lots of miscellaneous stuff.

These in here are actually, uh, resistor Networks dead giveaway are there. So and lots of you know, basic stuff. There's some 74 HCT stuff happening around there much a lot more precision opamps, and there's probably some multiplexes in there and you know all sorts of Jelly Bean type stuff. Um, curiously, check out this one.

70k um with 1% marked on it they got 70k 0000. It looks like one of those um Precision film resistors you know you pay like uh, 20 bucks for but it is marked 1.0 0% Don't know what's going on there at all. and uh yeah, there's more stuff happening we'll have to check out under the shield under there, but there I can just move it out. there is Tada no surprises at all and little devices.

637 true RMS converter. but um, yeah, that's basically the uh front end. pretty standard looking. uh, front end quite well designed for a multimeter.

It's got all the requisite uh protection. Not sure this one's not actually cat rated. Actually, it's designed or pre those cat uh ratings. So I don't know what it would be uh rated to rated to uh today.

but uh I'm I'm sure it is I'm sure the latest one is uh branded I just haven't read the manual on that. and the ADC You can see that's really separated from everything else. They got quite a lot of uh, ground planes surrounding that sucker. And of course the ADC is quite important.

but by the nature of it being separated from everything else with no surrounding components, you're going. Aha, where's the bypass stuff? Well, it's got to be on the bottom of the board. so this is obviously a jewel sided. uh Jewel side populated board.

so I'll see if I can get it out. Um, could be a bit of a pain a ferite in there. There it is. It's not just a uh, pretty piece of plastic to hold the wire in in place.

Now, as far as getting this board out goes, There were two screws on here holding this back panel in place. There was a screw here holding this uh linear regulator down to a little side um, flange there, using it as a heat sink. There was another screw up here doing a similar thing. So I've taken out both of those screws and there's little sliders um, on the side of the case here.

So I'm assuming that the board will just no of a du. Of course I've got to, uh, undo these connectors here on the the back. but if I do that and maybe I don't know about the AC input there. but it looks like the whole board is designed to slide out once you disconnect all the cables.

But maybe I should actually read the service manual? Nah, of course we have all our fixed wiring. Do they just ah, there you go. They're just uh, so sockets that just, uh, pull off the input. Very nice.

Yeah, there it is. Check it out, we can just pull those off I Really, really like that I better actually. uh, remember where they go H Aha I think I figured it out. These little slider notches over here and designed to slide so the board has to actually slide that way.

has to slide into the case instead of pull out. So I've got to disconnect all the connectors down here. The board slides in and then should lift up. Excellent.

So that's why we had the big cut out in here cuz the board is designed to. Once it moves in a little bit, it can then lift up and clear all of these connectors. and uh yeah, that's pretty good. I Rather like it.

So disconnected all that that should slide forward to the r and of course all these wires are hand solded. Oh, we got our connecting rod there. maybe we should. Oh how take the connecting rod off? doesn't look like it can.

So very carefully. very gingery. lift this out and then the connecting rod comes out of the front panel and oh it's rather tricky. bit of a hotch poch.

There we go. We got the connecting rod out there. we go. Tada Let me check underneath.

we got some plastic flapping in the breeze there, but uh, that's not not too bad. once you know, look at that. There we go. Tada We flipped it out of the way.

not a problem and there is our complete board and as suspected, yes, double-sided load. Of course all of the uh, passives on the bottom. pretty much. there's no sort of real, don't see any active uh stuff on the bottom and all.

just all. there's our ADC up there. remember our ADC was in that uh, complete section over there. there's the Uh.

A couple of you know it's only got a handful of Uh bypass caps down in there. We got a sells nice little plastic uh isolation Shield there, obviously so uh, you know it doesn't come in contact with anything else and uh, some ground plane action and not much else. Oh no, see a couple of guard tracers. Let's have a look and here it is.

Here's an excellent example of some guard tracers. Those one ones there with the exposed Um tined traces there. Now don't confuse these with that Shield um, any any form of uh, ground, uh, shielding or anything like that. That's not their purpose.

Their purpose is not to uh Shield interference from these adjacent Uh traces. here. it's designed to prevent leakage from these tracers the ones outside the guard zone. So to prevent leakage from these outside tracers into these Uh pins in here which are going to be quite critical and how you can get that, well, you can get a contamination of your PCB flux residues.

You can get dust and dirt and grime and fingerprints and all sorts of crap if you got a very uh sensitive Um input. Noe Like some of these uh system, well, a lot of multimeters on the lower ranges will have like effectively. um, you know, many gig Ohms input impedance effectively. Uh, open.

That's why you see all the digits on the molts Range Just you know it just charges up because these things, um, aren't just 10 Meg Ohms. They're very high impedance nodes, so that's why you would typically want guard traces in here like this. So it just prevents um, any like surface leakage going across. And really, if you want to do it properly and if you got a multi-layer board, you put them on internal layers and uh, stuff like that as well just in case there's any, um, sort of leakage on the internal layers.

So these are really sensitive points in your circuit and you really want to prevent any leakage into those from somewhere else. Now, this guard Trace isn't necessarily ground. It is going to be the reference point of the of the sensitive part of the circuit that you're trying to prevent leakage into, so may or might may not be ground depending on the Uh system configuration. But and that's why the solder mask has been removed and they've got the bare tin.

uh, plating on there is to actually get when you have surface contamination on here. To actually get leakage. Uh, to actually get leakage into that reference point And that's okay. That prevents it just prevents outside leakage.

so any leakage at all is going to be confined to the reference point which is not a problem. You don't want it leaking into the other points in your circuit, so the reference node is fine, and that's why they leave that Trace exposed like that. So you'll typically find that in, uh, these sorts of uh, multimeters. Some people implement this incorrectly and all that sort of stuff.

Well, we won't go into the details, but uh, yeah, that's a really good example of a sensitive Um input circuit that requires guard. Tracy There's another example of how you're just going to put a guard Trace around one particular pin because you want to prevent any leakage into that particular pin. And what does that guard? Trace Protecting Surprise. Surprise.

Look at it. We have ourselves a P Channel Jfet J 17 and you can see the guard Trace running on top there as well, protecting this High impedance. jfed. No surprise whatsoever.

and there's another critical device Analog Devices Ad 706 a dual uh PCO amp input amplifier and you can see the guard Trace going protecting that pin up there and running right around there. These guys know what we're doing and there's the other one. You see it snaking around the jet there and all around there. m attention to detail.

Love it. So the reason for all those guard traces: surface leakage. That's what it's all about. contamination.

So these so nothing leaks into these critical pins. and there's all our true RMS converter circuitry around there. That was all the stuff that was under the Uh shield on top and uh, wasn't fully uh, shielded of course and you can see the input switch in relays and other stuff still around the Uh analog front end all around here. There's our input protection stuff and just running and the shield sort of goes over part of this part here.

Opto coupler down in there and here's that uh DC power input here going off to the front panel here and that's you can see the physical separation in there between the analog stuff. We got ourselves an isolation slot there and that goes up there to the main processor and Poers. All that, and there's our Mains input down there, all separate. They've got the rod coming from the front panel there.

It is beautiful. Comes all the way from the front of the Chazzy I'm a big sucker for that really nice um, earthing on the shazzy there. going directly over to the Uh filter over here which actually is a proper uh, common mode input filter and there's all the uh, different, um, uh. there's all the different wiring from that voltage selection um thing which I showed you right at the start that actually goes all onto the board.

That's rather neat. They've got that going all the way over there and then that selects the uh, uh, various um Taps on the mains Transformer which goes in over here. very neat. Got some more protection in there, check those out there Massive for the Main's protection and uh, that is done really really well.

Time now to take a look at the bottom board, the signal Gen and here we have it and look at this: Beast We have ourselves an Analog Devices Shark d P that's a huge quad flat pack there. it's the Adsp 21061 Shark DSP processor would have been really bleeding edge. Um, you know 15 years ago this would have been really hot stuff and we've got uh, three other zyink devices up there so it looks like um I'll have to get the block diagram of this it is in the manual but it looks like uh, this is our our generator here and then this is all of our output attenuation and filtering and stuff like that which then of course goes into the sockets right down there on the bottom. So uh, we'll have to look at what the other stuff is doing.

Thanks to the manual, we do have the block diagram for the various sections. This is the digital uh Distortion circuitry and we also have the block diagrams for the analog Distortion circuitry. we'll check out and the sign Gen circuitry around here, but basically there's that big badass uh Analog Devices shark DSP up there with it ROM and it JTAG interface and it main oscillator I think it's 33 MHz or thereabouts. and um, the Fpga little zyink down in there.

we'll have a look at that type. and of course, it's got to have an external E prom to boot that upon power up and then you've got optoisolation that just goes across. It looks like just you know, serial um interface going across some opto isolators because your output circuitry you want that to be totally is electrically isolated from the rest of your generation circuitry. So they're doing that really, really well.

So we'll take a look at these other block diagrams as well. So here's the Distortion analog circuitry. that. There's the block that we just looked at the digital circuitry there, but we've basically got our Um ADC Here we got a filter.

There's our analog uh stuff we've got now: ADC clock oscillator another Fpga controll in the whole ADC system with an E prom as well, so not a huge amount happening there. Then we've got our sinewave generator circuitry and as I uh mentioned before, it's got its own control Fpga as well. Gener the sign generator is u301. We might have a look at that puppy.

But then we've got the attenuation filter. and uh, the output. Um, the second output. That's the main source output of course.

And the second output there is either an inverse uh phase you can see minus one there. It either inverts it or it can, um, do it as a pulse output which is the same frequency as your output uh generator. So looking at at the Uh generator sign generator part of this thing. there's our Uh Generation Um Fpga there.

and surprise surprise, we got an Analog Devices Ad 9850, 125 MHz DDS generator. These puppies are everywhere. We saw one of these in the last tear down as well. they're all over the shop.

Then our DDS goes into an Amp3 another Analog Devices part. that one is a Unity gain differential amp and then as I said, it goes all into the filter stuff and the attenuation stuff which is all around here, relay switching and then you got your outputs over here with some uh common mode chokes as well. And all three Fpga in this are the same. They are Ay links, ancient, obsolete by the way.

Um XC 522s a lousy 3,000 Gates each and the Silicon process technology5 Micron Huge! We've actually got ourselves a Second DDS generator down here. and there's the main ADC Analog Devices 7722 uh, 16bit 200k sample per second Sigma Delta converter. and obviously this is the Um Uh main ADC control Fpga so that's taking care of all of that. And over here you can see the opto oscillators with the isolation slots down in there separating all of the digital circuitry over here the DS p and it's control Fpga over this digital link which then uh drives the ADC and then that dries all of this generation stuff and completely isolated from all the digital section.

And then we've got uh, some of the feedback going up to our main Um multimeter board as well. These are just wired directly onto the board here, flying leads up to the top. Even the Transformers are made in the US OFA by North Lake engineering in Bristol in Wi is that Wisconsin and check out that slot system up there as well. They've just got a little uh, retaining um looks like pin on the bottom of the case.

so you slide the board backwards and then it just pops out through there. Very nicely engineered I Like that a lot. So that's a rather nice implementation of a you know, a THD uh generator and Distortion measurement system has got you know, 16bit 8 see in there Fpj's Dds's to generate DSP Processing the whole works to uh, add this rather unusual THD capability to this Um System multimeter. I Think it's the only multimeter on the market that's got built-in Um generator and THD so rather unusual little beast.

and uh, certainly if you can, uh, pick one of these up. um, you know you might be able to get one fairly cheap cuz people don't really understand this model. they go t HD What? what? I don't What's that got to do with multimeters? I Don't know I'm not touching that thing. but uh yeah, it's um, not bad at all if you can score it for a decent price.

So that is a look inside the Keithly Uh 20115 THD and if you know how it, uh, if you got photos of the Um 2000 uh model as well which uh, presumably this uh, this top board is identical to the 2000 then uh, uh by all means, um, share it with us and we'll um, see how the internal uh construction differs to the Uh 20115 so it' be interesting but that that is quite an interesting bit of kit. it's rather unusual. um it's above and beyond your usual um bench multimeter tear down so that's very welld designed and manufactured instrument. I'm not sure what it cost brand new I think it's like, you know, $3,000 or something like that.

uh, brand new. So if you can pick one up, um, especially that it's a current model for one10 the price. Oh man, what a bargain. And based on the date code of some of this stuff, I mean you know there it is the 39th week 04.

So this one that I've got is less than 10 years old so not bad at all. It should give some really good service. One thing, um, that I didn't find in here of course is a uh, backup battery. like you're getting a lot of old multimeters to hold, you know, calibration data or something like that n none of that to worry about here.

So there you have, it looks like an absolute mess and uh, I'm sure it'll go back together and work a treat. And as always, uh, if you want to see some High resed photos of the tear down um, my flicker account is always uh, linked in there. So go check it out. and if you want to discuss it, the Eev blog forum is of course the place to do it.

If you're not on the damn Eev blog. Forum why not? you should be. It's where everyone hangs out and chats. Oh man, there's like 600 posts a day or something.

It's crazy. If you want to ask questions, don't send me a personal email, jump on over to the Forum Someone will answer you quick smart. That's a beautiful thing. I Love about the EV blog.

Community You ask a question. somebody knows. somebody's got the answer to it. Always it's and they bang.

You know somebody will just know the answer to your problem off the top of their head no matter how obscure it is. It's really amazing. Never ceases to amaze me anyway. um I hope you like the tear down on this keep 20115 and um I'll probably um yeah.

I'm going to this is a keeper of course. I'm going to use this here in the lab and um, very nice bench multimeter a bit Limited in some capabilities, but uh, I'm certainly going to use it and I'm going to try and use the THD feature of it as well. so I might have to do a video on that once I get it hooked up to a PC run the Keithly software which I think you can download from the website and do all that THD measurement goodness. hope you liked it.

Catch you next time and.