Hi I did a recent video which I'll link in down below at the end. if you haven't seen it where I looked at buying a sub 200 US dollar six-and-a-half digit bench multimeter on eBay and I found really not. didn't know too many problems actually find him one available so I decided to just rather just do the video I thought hey-oh order one. So I actually got one for a hundred and thirty dollars plus $20 U.s.

delivery to Australia So a hundred and fifty US dollars plus they automatically had a GST on that. There are the strain governments change differ in ports they're paying the ice, but I can claim that back. So a hundred and fifty US dollars for a six and a half digit Moldy meter. But yeah, this is how it came.

So yeah. fantastic packaging. It's always a crapshoot when you order stuff and unless you really get it from one of the professional like test equipment of resellers, they'll generally pack them okay. but this one terrible.

Muriel So this one was sold as like it was just like powered up. It showed something on the display but apart from that it was like might have even been sold as part. so I think. But anyway, let's open it up.

That's one sick puppy. There's certainly an art in packing test instruments for shipping, especially like overseas, which probably gets more abuse than just the local postage system. But anyway, yeah, this is how not to do it. Of course your professional sellers they'll use like the vacuum-form d What have I got there? We go.

Well that's not gonna be of any use to me. Is it bloody? Yankee Leave um yeah. Thanks for just whacking some bubble wrap inside that with like just put in a bit of bubble wrap on top and a bit of a bit of cheap paper. We've wrapped fish and chips in paper like this here I don't know about but that's where this one came from.

So yep there's nothing else like in there. they just so it heads. just some bubble wrap on the top, wasn't even wrapped around the instrument and well hey it's look it's a well look there it is there. it is there Wow Okay, it's not crushed.

it's not crashed. Jeez, that looks in good Nick doesn't it? Yes it's a the one that I showed I think it was one of the first ones I showed in the video the Phillips PM 25 34 and they had a couple of these. Apparently they had three of them and I got the last one I think but that looks ah no. I thought those buttons looked a bit pushed in the air.

Boom generally looks in good Nick doesn't it? Unfortunately, my 350 bucks you don't get the banana jacks on the front. that's a shame. But anyway I'm not going to complain if it works for a hundred and fifty bucks. So it's got all the records of stuff on the back it looks in pretty good Nick I like it and that date code down in there is it? I assume so looks like it 1994 Xlvii weeks.

So yeah it's it's 25. Oh wow. 25 years old now but still looks looks like a bought one. it is.

Beware when you get stuff, this is a hundred and fifteen volt unit says connected for a hundred and fifteen volts. But considering that it's got the different fusee things in there I think we should be able to change that. Can we set the path? Wow, that's a weird-ass power switch. Actually, this is one fascinating fuse holder.

Look at this. I think I've seen this one before. Look at that. We've got two contacts in there, so I presume it was like designed for maybe different voltages Oh lifts up like that and then that slides out like that I can keep a spare fuse in there I guess but yeah, maybe this was for the 240 volt version, so maybe we can't actually get the higher voltage inside? Hmm I should I take it apart first instead of pairing up? Yeah, take it apart.

You know. The good thing about this Phillips meter is that not only is that quite small and compact for a bench multimeter, but it sliders as well. Which means for especially for international shipping doesn't cost much. As I said, this is probably the lowest cost shipping I've ever had on a instrument this size like 20 like 1995 us to ship this thing unbelievably cheap.

Uh-huh I was wondering about that I thought oh yeah, like if it works and everything's hunky-dory you could always like retrofit some banana Jack's on the front. and of course you could design a PCB that fits in there nicely. I only got a single screw, but it can go up into there and what is that? Oh yeah, it's got a little plastic hook so you could you can actually design a PCB to actually do that, slot up and slot up in there like that you can have it. PCB with the little slots and I know they're on the inside.

Oh well, I'm sure you can figure out a way to do that and then just, um, have a screw hole and put in and boy or a mouse through to the back. Now don't see any calibration stickers on this thing at all, which is quite unusual. Usually you were you know might find at least one calibration sticker or something. but deputy Duda that's the original fluke the seals but yeah, biggest like fluke board out Phillip so it was fluke Phillips but this one is old school.

it's branded Phillips okay okay, thanks. these like cottage things just fell off. Okay now I only make this a very quick teardown because I want a power the thing up and get it, see if it actually works. That's the whole point of this video.

but that's neat and tidy. Isn't it all the yar the acquisition inputs, our side of it's all in one big-ass shielded can like that and oh god I know that's a just a plastic insulating thing on the bottom of the transformer there. uh-huh uh-huh I See it. I See it? hang on.

Got all excited. 230 volts 115. It looks like I think we break those two like that and just join the 230 there. But I'll confirm that with the manual beauty and that's what you want with the sort of instruments you want.

One definitely check the manual before you buy it. I didn't on this one I just assumed I did you know I Always wonder. Buy it quick and but yeah, do your research. Read them.

download the manual for it and it'll usually have like whether or not it be can be configured for different voltages for different reason or regions like the back panel. Here it's all just sort of like flapping around in the breeze in it. They've got this bar that goes from the it's like plastic. that's the only thing holding this thing together.

cheese. it's not terrific. Oh, not impressed by their by Philips there. it's not not the best at all, but once it's all together it's fine.

but mmm. The great thing about this is that it's all old-school dip. So very serviceable. I Don't 8:03 one processor with a ROM We've got ourselves a Lithium battery down in there.

It doesn't look like it's leaked so you could replace that. Hopefully that doesn't have the calibration I Think it probably is keeping the calibration constants. So yeah, you don't just don't want to go whipping that out willy-nilly with you have to use our certain techniques to I keep your volatile memory intact while you change the battery in this thing. But I'll give that a measure.

But yeah, I'm really quite easy stuff. There's cereal and GPIB pour it down in there. no workers I won't bother going further with the can and everything. I'll just check the manual and get that switched over and we should be able to power it from 2:30 which is now the official voltage here, by the way.

but this labs like 247. Ok, so we want to check the primary resistance here. There you go. 45 Ohms.

So for the 230 volt version, we expect to basically double that because we want to put both. usually are. they have a split coil on there so we want to put those in series. Let's see, that's the idea.

and you can actually see the wiring configuration here. Here's your mains input here and here and you can see that basically they do where your problem. Yeah, you can just see the shadow of the track go under there. So it basically goes to this pin here and then it jumps over to Higgs we've got to jump out.

Then it goes to this pin. So here's your two coils. one here and one here and you can see that that's in parallel with that one there. And then we've got another jumper link here which puts the other side of the I Guess I'll call that the top coil there.

and then it jumps over to the bottom coil so you can see that they're in parallel. So if we short out those two there, bingo, we should join up my basically joining those two pins there and we're putting the two coils in series. That gives us our 240 volts beauty. So there we go.

Just got the jumper in the middle now and let's measure the primary again. Let's have a look there you go: 160. It's higher than double the 47 we had before. We had two coils in parallel.

so we'll just get in half the actual single coil resistance there. So there you go. That works. A treat.

It should now work perfectly on 230 slash 240 volts. We're not just check that battery there 3.17 That should be fine. So yeah, no need to replace that yet. Or though a lot of people waters matter, of course it's you know, 20 and what did I say? 25 years old? Hmm.

but still good. Oh these plastic guide rails they actually slide into the case their need. And when you're changing mains voltages like this, make sure you get the correct mains fuse as well. All right, tie the power this supper up.

let's go. Beep! That's good Point: Oh, it just jumped a 6 and a half. Teachers are sorry, yeah, you can't see that, can you? Jeez, that's dark. It's dark on my camcorder screen.

Sorry it. It looks much better in real life, trust me. Hmm. Oh hello sailor.

Ten Point Zero Zero Zero Zero volts. That's only five and a half digit mode. Have to get to six and a half digit and just we compare that. I've just powered these on so nothing's like warmed up or anything.

So yeah, if you want to do this properly, you've got to like leave it for days and days and there. Yeah yeah. Anyway, these are my two seven-and-a-half digit DMS and there we go. Nine, nine eight.

they're both being so you know you can argue it's slightly out compared to my to reference meters. but geez, even though we got 10 dialed in here because as I said yep, it's not warmed up yet and we know this is bang-on because I've calibrated that maybe I had to link that in at the end of this video. But there you go. it's for voltage.

It's well within specification and this is what I said in the video. If you get these six and a half digit meters they might not much really goes wrong with them. So if you see it powered up and you know it appears like all pulled from working environment or something like that, you can be pretty sure that it's still gonna meet its specs even after 25 years. So we'll just push our speed button here.

There we go and oh there we go. That's a bit blow up. There we go. No, is it gonna It's gonna take it like a second or something per sample.

But yeah, it's a little bit high. but I do believe I don't even know I don't think I need a calculator to know that's still within spec. But as I said to do this properly you've got a like leave everything warming up, the reference has to warm up and stabilize, etc, etc. And if I get the old confuse are out there, there we go.

we're talking about it is a point double o1 8% high if you take the keysight seven and a half digit one down there as the reference. so that is even within the 24 hour specification I believe. And as four hundred millivolts, let's have a look point 100 point Oh four 3.0 39.0 for one, that's pretty darn close happy with that. As for the resistance standard, it's about three million.

Ohms is low. Is that still within spec? No. Turns out that's slightly outside a spec. The spec for this meter I mean you know it's a 6.5 digit meter, but as I said in the previous video, the specs do differ.

It's not a patch on, say the six and a half digit version of the key side here. the three dollar, four, Six one. Oh, for example, just because the six knife digits doesn't mean the spec is spectacular. Pun intended, it's point O 3% one year speck plus the counts of course if it's slightly out so it's not bang on.

but jeez, you know, for a hundred and fifty bucks I don't think you gotta complain. So I've actually had this running for a couple of hours now to let us stabilize. And of course, I was using ten volts before. This is actually a well 303 million count instrument.

So it's range is like three hundred millivolts, three volts, thirty volts, 300 volts, etc. So it's better to put it near test it practically on the full range rather than that one which is like 10 volts or 1 volts. For example, 100 millivolts which is at one third of full scale. You know the accuracy is going to be better specified near your full scale.

That's why they calibrate these things very close to full scale. So I'm feeding in 3 volts. Now from the calibrator, you can see it's not too shabby at all if we have a look at the other two. Yeah, you know the Keithley is almost being on the keysight's new smidgen.

Hi there, But gee I mean it's pretty good. but the old Phillips up there we're talking point triple O3 Almost. You know who can round it two point triple O four percent. so that's not too shabby.

That's well within. Well, that's within the 12-month specification. this is after 25 years. Unbelievable.

In fact, that is within the 90-day specification of this thing. So Wow nice. Now the good thing about this meter is that not only can you get the full schematics and Theory of Operations service manual, the Whole Works of Service menu also has the calibration procedure and the calibration procedure is pretty simple and you can actually calibrate and you've got to look out for this sometimes is that you can actually calibrate individual ranges as well without out I've said in the others. so if only one range is out for some whatever reason because I don't know something to do with the voltage divider inside or something like that, you can actually you know trim out individual ranges, but in this case you wouldn't touch it.

This is actually closer than the keysight and just for kicks will do 30 millivolts. It's actually once again slightly better than the key site down here. neat and 300 millivolts. there you go.

It's a little bit more as a little bit further out than the key site, but once again still well within spec. but unfortunately resistance is still a little bit low now. I'd Like to be able to calibrate the resistance, but unfortunately you've got to feed in like person. You can't just feed in any value on there like enter in the value that you're feeding in, you've got to feed in precisely 30 K for example and I don't have? Well, I could get precisely 30 K and then of course you know, use these as my reference and then do it that way.

But yeah, and if I hook up my AC voltage standard here. Unfortunately, the resolution. you can't get greater than that on the AC volts. Not terrific.

but there you go. I've tweaked it, so it's it. You know, pretty close to three volts there, so it's okay. But really, this is not an AC instrument that's for sure.

And by the way, if you're thinking that six off digit meter would be great for low current stuff, well and not this one. Unfortunately, it's just got and amps range which you know, milliamps, that's as low as we go. So yeah, only like point 1 micro answer Resolution: It's pretty peaceful. unfortunately.

I Think the fuse is blown in it because I can't measure any current at all. You know what I'm gonna do is just take it apart Again, Get this off because if you have a look at this panel here, it's absolutely looks absolutely identical. The screw the two things. The probe interface is exactly the same as the front, so I'm hoping that in fact I think I just proved my theory.

I'm going to be able to move that panel from the back to the front. A lot of people have probably already screaming at me, but yeah, that it looks like I can do that I can see the wires in there I Think I can do it. Let's go. Looks like you just take out these two.

Roo's his slides forward and pop out of there? Nope, not without a fight. Oh, it's stuck under there. Is it? Alright Here we go? Nope. Nope.

got it. we're in like Flynn I spy some flux residue and hands solder in there and hear that Oh like a relay or something. I it's not a really quarter and up here. so I spy some hand soldering? Is that this had a repair and maybe maybe over there as well because everything else is wave soldered and there's a couple of clips on the underside of the front panel here.

If you get those off, you can move the front panel forward and you can get eventually get this turned off. I'm sure there we go. Uh-huh and it's exactly what I thought it is because they have different models for the I Believe for the front and rear panels. here's where the connections are.

We can just whoa-oh-oh-oh that's why it wasn't measure in the current look look. it's been port let the terminals have fallen off. These are just like turret. Wow I Could I can really pull that off quite easily cuz there's our we've got a ceramic fuse in there.

Here you go, you can see that Well tuck towei in there. sand. Not a terrific design. You got to take the whole thing apart to access the fuse.

That's pretty piss-poor let me tell you. But Wow anyway. Oh Check out the little. Check out the relays.

Check out: They'll literally read relays. the coil on the outside of a reed switch and another pair down there on the main board. match in red and green. Ah, beautiful, real fading.

can realize those things. Bobby Dazzler Well, hello, Mr.. Wire Badge. Look at that.

Does anyone know if that's oh yeah, no. I Reckon that. I Reckon that's legit. Look at this.

It's going into this thing. That's what. Is that. What on earth is that? Wow That is actually some ridiculous low leakage read relay.

I Believe Cceres are basically there's a coil. There's there's a pin there, and there's a pin over on the other side there, which goes down to the PCB and wires go in there because they're freestanding. You can tell you're at all a really ridiculously low leakage point because look at all the isolation around here and supplies they didn't like. Cut a slot in there or something like a circular slot around that thing.

Yeah, that's that's what it is that is fascinating. If anyone's got a data sheet for son. I Don't one of those babies please leave it in the comments and we've got another read relay over here. Well, then here's our current shunts.

Look at these nichrome wire wrapped around a soda that's a ceramic former. I Think yeah, hey. I know, let's put the chip under the fuse. why not save some board? Real estate.

So anyway, we had two wires flapping around in the bees. this gray one just on the weight, just based on the way it's formed because there is no labeling down here or anything like that. The you know, maybe look at the schematic in the service manual and whatnot, but I'm pretty sure that goes into the Common of the Ants jack. And by the way, this thing doesn't share a common between the amps and the volts by the way.

and this one's actually the guard terminal which sneaks in around the other side. There There it is right down there and there's a switch on the back that allows you to switch the guard through to the common for the voltage jack. and you don't really actually have to guess with that. and you don't need the service manual because the blue comes down to here through this resistor down to, you guessed it, shows E ground.

So to get that out and move it to the front, that's why they have the pins on there. I've got to pull all the pins off. gotta remember where they go and just to get that out. Otherwise I don't Yeah, she's not gonna budge.

All right. Somewhat annoyingly, it looks like the and all back panels got to come off. otherwise. I can't leave her it out by God Oh It was a struggle, but I got it out well like I Never expected this.

How easy is this? This is fantastic I Never got a front port and system multimeter. It makes perfect sense. And of course, what chips are you gonna find in here? We'll all Philips branded are No. I spoke too soon.

not semi. the Philips didn't make that, but they make almost everything else. no other than that semi in there. But geez, even this puppy look single inline package.

jeez, you don't see many of those. What's an SS a 1300? Some sort of ant looks got a little power fin on it as well. Hmm. and there's your opto coupler interface.

And of course right down there there's the isolation between the digital and the analog section. or goes over via the digital isolator. There they've got another Philips Now that's probably added like a comms thing to go over the isolator. What else is not much doing actually? Where's Wally? Where's the voltage reference still looking? And of course more isolation up here to go around between the cereal and GPIB and the rest of the analog stuff.

So where is our myself voltage reference? I'm not seeing a Lm339 where is it? Come on. I'm starting to suspect that little silver beasty down in there. Nothing, no label on the top that's looking suspect and it turns out all those parts that had those that have been like resold adorn hand soldered. Basically, they're all the reader relay stuff in here.

So yeah, that explains that. they obviously didn't put those through the wave soldering machine. Do you believe you'll find that thing is as inner in a little you know, round like to5 type but squat packaged. It's a two terminal device, so it's got to be a Zener reference.

There's no problem with that, but you've got to remember my M Viii 106 voltage transfer standard, which is better than this, has just the same thing. it's just got a regular Zeff Well, it's just got a super stable Zener that's been hand-selected by nude graybeard virgins and they're probably a similar thing here, but just maybe not virgins. Well, it turns out under the right angle there, you can see that that's actually a national semiconductor. LM one three.

Well, it's one three six. There's actually an LM one 36, which sure enough is a 2.5 volt Zener reference 20 ppm. So so that's what they're using in this baby and who knows, like they might have them. you know, specially selected or something like that.

Perhaps it turns out I can run a self check here I think I haven't read the manual but I managed to figure out that I can go test one like that and then press end up there and soft Oh seven and then we get all the digits. There we go It's got a two-digit starburst. neat and then it boom. Okay, no problem and of course I reset and cowl there to do with the calibration.

As I said, you can individually I calibrate the like individual ranges on this which is very nice and unfortunately for the temperature mode looks like you need to use the probe because irregular K-type thermocouple in the jacks doesn't work. So there you have it. There's the PM 25 34 Systems multimeter from Philips / Fluke and this is available like in a much older model in like the old-school Philips look and feel from the 80s. But yeah, this one certainly dates from 9 to in the mid 90s 25 years old.

but as you can see, it mostly meets its specs. After all this toy, it's amazing. Yeah, it may need to be recalibrated on maybe the Ohms range and I do you know I don't know I haven't checked all the ranges yet. It takes you know a long time to comprehensively check everything and it certainly its specs aren't gonna set the world on fire in terms of a six and a half digit multimeter.

but geez, like for a hundred and fifty bucks, you're getting an awful lot of meter here. It's absolutely amazing. 150 US dollars delivered to Australia So it certainly is possible as I said in that video, to get like a sub 200 or a $200 six-and-a-half digit meter. and I did even better than that delivered to Australian This looks like it's a winner winner chicken dinner.

and certainly you know specifications meet its age. No problems whatsoever and it had not only a fascinating build and construction, but I was able to transfer it from the rear panel to the front panel just by doing that. I was able to easily convert it from a hundred and ten to a 240-volt unit. No problems whatsoever, and it's just a terrific meter.

Service manuals available. The schematic is through-hole you can repair everything. so I think that's just fantastic value for a hundred and fifty bucks. Unfortunately I can't like that.

trust me. That also don't know what's going on with the game. It doesn't look terrific on my camcorder screen. Looks like the I can see it with my eyes, but I don't know.

there's something just up with the angle of that. Trust me, it's better than it looks. but yeah, sort of. someone got a solder annoying to that key there, but isn't that in great? Nick for a hundred and fifty Yankee bucks winner winner chicken dinner.

If you like that video, please give it a big thumbs up. And as always you can discuss and down below and I'll linking that previous video of how to search for you know these kind of bargains on eBay Hope you liked it. Catch you next time.