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- Опубликовано: 27 авг 2024
- This was supposed to be a repair video of a Fluke 17B multimeter.
But embarrassingly turned into an impromptu How a Mulitmeter Works video.
Dave goes through the Fluke 17B schematic and explains how stuff works.
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Dave, I appreciate that you are not too proud to share your FAILs with us! Good on you!
Thanks for the humor. By posting this you have us laughing at ourselves. A needed relief for our moments of grace.
He thought it was going to be a problem, but it turned out to be a FLUKE. hahahah
Great job Dave. Most people would delete the video. You turned it into a learning opportunity. Thumbs up.
That was very unexpected, thank you for making the video and setting the record straight, with honest information we can make informed decisions and move forward.
Nice to see the meter I sent in for mail bag once again. I haven't see that in years. I thought you might had sold it. It turned into an awesome tutorial on DMMs. Thanks.
+Todd Harrison (ToddFun) Thanks Todd. Yeah, kept it just for such comparison videos as the Brymen one.
+Todd Harrison (ToddFun) Hah, looks like it still has the protective plastic cover on the LCD.
+blargg Sure does. He drives me nuts leaving the plastic film protectors on his meters and he knows it too.
+amadrunner HA. good one. I bet I type it wrong all the time too. Thanks.
+Todd Harrison (ToddFun) just looked at your channel and I like it. Subscribed! (also, you like saying HA, eh?)
Hey EEVblog! I'm currently teaching myself electronics! I was inspired by my father and you :)
Dave, thanks for the video and the honesty. We all make mistakes, and you did an excellent job turning this video into an epic DMM tutorial. Good on 'ya.
I couldn't stop looking at the unpeeled factory screen protector. Ahh!
I love how you didn't delete this video and actually made it into something useful.
this video makes me feel good because if a pro like dave can dismiss an idiot moment like that i can laugh at myself for being an idiot at times too thanks for the confidence boost dave
Good on ya for being honest. We're all only human after all.
+Nova Light I'm an Advanced Cybernetic Intelligence (ACI). Because "artificial" is a prejudiced term. ;P
+Nova Light I... am a meat Popsicle ;-)
I just discovered this channel and have spent the better part of my day off watching videos. Great job, Dave, really informative and amazing!!
+Joseph Christian Thanks. Only 800 or so to go
EEVblog Well I've one more day, cheers!
+Joseph Christian it'll take you weeks. hope you don't have any plans
I've still got and use my Fluke 19 15 years later.
+thefamilyman
I have 2 of them for the price they were good value, but i must admit the first one had to be replaced by Fluke due to some problem similar to what Dave described.
cant remember how long I have had them, quiet a while now still giving good results.
The 17B and the 19 are very different. I've got both, plus a couple more professional Fluke meters on my bench.
I still use a Fluke 19 for lots of day-to-day stuff. I must have been lucky. The thing's been reliable and accurate since I got it (from the local Tricky) in about 2000. It's got the fast updating bar graph and the good touch-hold.
3:52 Where's the FAIL button???
23:40
I must be tired, when Dave said "increase in value" I thought "really? The part gets more expensive?"
I guess the fluke needed to get screwed.. LOL Happens to the best of us mate. Great explanation - thank you
So a pretty decent and accurate meter built from cheap components using clever design tricks. Looks more than good enough for home hobbyist use and it has the magic name on the case.
Thank you for this great video Dave!! That was really enjoyable and educative. And also thanks to @Todd Harrison (ToddFun) for the contribution.
The mark of a good performer. Something goes wrong, pick youreslf up and carry on. Thank you for being honest about the screws.
Very informative video. Thanks. Glad you didn't delete it.
This is why we watch your channel! :D
I wonder if Fluke would make a jig that auto tune the pots? Even more saving on top of saving $4 with cheap labor
this was... unexpected
Opps which then became a very interesting how to design a multi-meter. Thank you
For fun, you could add a photodiode and a resistor to enable the serial port on the FS9721-LP3 (assuming that is actually what is under that little black blob). Google around to see how it is done, it will give you a fully isolated serial output which is compatible with Qtdmm and a few other software DMM interfaces.
Its probably marketed as an HVAC dmm hence the temp accuracy.
Very good video
This is enlightening. I am thinking about creating my own multimeter design but I have to mix and match chipsets and microcontrollers.
I wish I understood all this stuff haha. I can hold on to more than I used to. Im just now in my electronics circuits studies (semiconductor devices in AC circuits), and we're just starting BJTs, but it is kind of nice being able to watch these and realize that I understand more than I once did.
There is no flow of electrons in electronics; you might learn the hard way.
@@Crazytesseract there are though, particularly obvious in DC electronics. LEDs, for example, do not illuminate unless electrons are flowing through the PN junction and falling from a high energy state to a low energy state
This comment was from 6 years ago lol
@@toasty4000000 What do you mean by electrons in the first place? Just because observation somehow fits the theory (or vice versa) does not mean that electrons should exist. By now you may be knowing everything about dual slope integration, flash ADCs, successive approximation ADCs etc., in detail, voltage regulators, digital circuits, combinational and sequential circuits, amplifiers, oscillators, filters, capacitors, diodes, BJTs, JFETs, MOSFETS, FINFETs and so on with all the details of their working and you may even design them, but don't assume electrons exist as you have been taught all these years (particles with a negative charge).
@@Crazytesseract You've got to find a better hobby than going back on decade-old videos about beginner electronics and trying to dissuade people from the hobby with shallow intellect.
@@toasty4000000 I am doing nothing of that sort. And I am saying to people in general, not you specifically. You may not know that you are strongly trapped in illusion, the experience of this phenomenal world is a kind of virtual reality, a very strong illusion. You may one day realise that whatever you thought you knew was totally wrong in many aspects. Have you probed into macroscopic quantum mechanics and objective semantic information? Relational properties? A car driver can drive perfectly well and yet not know how the car internals work; similarly scientists and engineers may use science to use electronics, design circuits etc. without understanding how they actually work. Not saying that they don't understand anything at all, but many things. I do not wish to discuss more.
May we please have a review of all the other meters that you have only torn down but never shown what they are like to use! The Agilent U1733C springs to mind.
Thanks for posting the vid even though it was a goof up... It's just too easy to sweep things under the rug. Interesting video in the end!
Thanks, I'm, just learning about this stuff and the video helps.
I wouldn't have noticed the missing screws until already having replaced at least a capacitor.
great video. Can you do one for oscilloscopes? In particular how the acquisition circuitry and trigger works?
I like how you automatically condemed it before even taking a look. A bunch of ppl likely threw theirs away withour watching the whole video. hah
Might be worth placing an annotation at ~16 minutes into #852. This may not be the pinnacle of multimeters, but it didn't fail.
Had a good laugh. And at least you're honest.
Stupid silly mistake, everyone does it.
Great video. I truly enjoyed it. Keep them coming.
If you had to guess, how much does everything in your shop together cost? I've noticed you have some *_really_* high end stuff lying around :)
Great video, lots of clever design in there. What about the tempco of those trimmers? Gotta be bad!
Yeah, Dave. Went back and looked at that teardown, and sure enough, you end it with no screws. BTW, these are on ebay all over the place for about $115-130 USD shipped free from China. But I like my EEVBlog Brymen 235 much, much more!
16:53 you forgot about the fuses which may add up to 1 ohm on the path
The clamping on the ohms range might be in case you plug it in to a voltage source on the wrong switch just to give a little protection.
"And I just took that screw out and I really had to put a lot of force on that to get that out..." [Dave Jones, 2012]. "It looks like it died, and I don't know what is going wrong with it: It's just been sitting in the box..." [Dave Jones, 2016]. Yeah, right: sitting in the box... Great video as always!
I have to say, as an American its an absolute disgrace to see our once proud companies decide to slap their name on some made in China bullshit so you think your getting a quality product.
+Nutz4Gunz45 As an American, The older I get, the more I realize that the notion that America only produced great stuff in the past is completely wrong.
Putting cheap garbage in shiny boxes is an American national pastime. So much so, that we had to create expansive consumer protection laws. What's different about americans is that while we love ripping people off with cheap crap, we abhor the concept of Caveat Emptor.
+Nutz4Gunz45
China can make good stuff *Looks at soundcraft mixing board with high quality components, Rotel amp, the power supply in my PC that has been running for quite a while now, the chinese tube radio from 1968 on my channel...* You just have to pay for it.
Those once proud companies have to find a way to survive in the free market system, in the perverse race to the bottom of price and quality.
I'm no saint. I buy cheap crap too. But i'm also saving up to buy a set of tools of very high quality that will last for a considerable part of my life.
+Nutz4Gunz45
The problem with this "made in China bullshit" isn't that China can't produce quality. China is just a more radical implementation of a free market economy (the system we all love and profit from). And as such, it provides customer-oriented ranges of products. Everything from high-quality expensive down to cheap crap, whatever the customer wants. Needless to say that those proud companies you speak of don't chose the opportunity to get good quality for a fair price but keep asking if China can't make the cheapest products even cheaper, in order to increase their profit margins. Which is obviously a pretty stupid and short-sighted decision, because the consumer starts to realize that buying a brand-name product isn't worth the money since he could get the non-brandet version for a small fraction of the prize (and not stuffing money for drugs and hookers in the pockets of companies who do nothing but putting their stamp on things they neither develop nor manufacture).
+SlocketSeven Partly so. Let's talk about guitars: There's a reason why artists from all over the planet will pay several kilodollars for Fender, Gibson, Jackson or PRS. That's outstanding, proven quality.
Let's talk about planes: As a student, I worked for the german sales office of Mooney at Bonn-Hangelar airfield. Uttermost sturdy, reliable beasts, that will go like s*** from a stick, based on a design proven over decades.
Beechcraft, Learjet, Cessna, Rockwell, Boeing… all leading names in the industry since dunnowhen, and they have earnt their good names.
I myself am rather fond of US cars as well. If you don't mistreat them, they'll last almost forever. An uncle of mine owned a 1981 Buick Electra since 1990 until well into the naughties. A brilliant crate!
I guess what it grinds down to is that cheap is cheap, no matter whether it's produced in the US or Malaysia.
The good stuff still is out there, only the price tags make your eyes skip over them. There are pretty high quailty products made in Chian available now, but they aren't cheap either.
There probably is a similar thing going on in the USA as is in Germany: If you'd have to buy the work you do yourself from anyone else, you'd have to invest several hours of earning to be able to do so.
+satoma satomis I would, but you Swiss don't like foreigners, and it's impossible to become an immigrant.
Unless by marriage and I've had enough of that to last me the rest of my life :)
Hmmm... minor point; if I remember correctly from A&P (Airframe & Powerplant) school, most all ammeter shunts are not nichrome, but a special alloy called 'Manganin'. Also, if a Manganin shunt is ever overheated, it can/will go out of spec. It was back in the early 70's, but remember they seemingly had a 'thing' about shunts and spent hours covering them...
Looked it up... pretty sure I'm correct, check the 'Shunt (Electrical)' and 'Manganin' Wikipedia entries. Cool videos, thanks!
Great video, goes very well with my next project. I'm going to build a digital dc voltage / current meter with a 24 bit adc. I just haven't decided how to go about range switching, I don't need many ranges, 50v / 10a max. this video has given me some ideas, thanks
The PDF's not mangled, that's just how bad the output from Cadence's DEHDL schematic tool is. (Font support wasn't added until 2010 and it still doesn't support colour fills)
There's an EEVBlog multimeter? :o
Want!
LOL!!!!! That was great Dave Too funny you forgot the screews!
Perhaps Fluke was testing design prowess of their new team Asia? Just a thought.
sorry to respond to my own post, but what I mean is that Fluke said ok design it, put it in production, and let's see how you do. They have the money for such experiments.
I've done just that - both on a meter similar to this one, and a 25/27.
Generally, one shouldn't have more meters than one needs to use.
Doh!... Anyway, I don't mind all the trimmers. The advantage of those over closed case software cal is anyone with a good reference and a schematic can cal/adj their own DMM. I trimmed the DC V range on my 17b to correct for a slight error using a trustworthy reference DC V source and now it reads exactly accurate. I haven't touched the other trimmers.
Well at least Dave's streak of not being able to find anything repairable is gone. :D
my father has a 19B he got from work it must be atleast 10 years old now and still works
I'm afraid it's "2 chips", not "2 chipsets" - it is a single chipset (i.e. a set of chips).
you could have easily ended this video after you tighten down these plug screws.....glad you didn´t done that...!!
GRTEAT video, thanx Dave!! You gave us some detailed insights to DMM stuff....!
Around 13:05 Did he just say they might crimp the nichrome wire if they just want to trim it "by half a bee's dick"? ROFL. I'm learning all kinds of new things here!
The oldest Fluke I have seen that use the "transitor as diode" protection is the 8500 from the early 70's
Dave, please do the red pitaya vs analog discovery 2 comparison video!
Every time I dropped a meter with pots its calibration was broken, I have always been wondering why this isn't a marketing thing that they write on the case/main info.
Have Lemons: Make Lemonade!
Where is the video about multimeter input protection mentioned at 11:20?
Hi, Can you help me?
The multimeter reads the probes are short connected even if the probes are not touching. I've tried to analyze the board, but unfortunately I'm lost. Can you tell me the steps to fix it? ..
Model Uni-t UT139e
was it putting out the 3v test diode voltage i wonder
Awesome videos man, I learned a lot from them :)
Don't even need to watch the video. The issue is clearly him not removing the plastic off the screen for 25 years.
4:00 Good on you for not hiding an obvious omission after reassembly. Most people would have tried to hide their mistake from the public :thumbs up:
A question Dave... What Fluke model Multimeter would you say is comparable to your new EEVBlog multimeter ?
didnt see any link to the schematic, :( so sad!
At the beginning of this video, those probes are keysight/agilent?
Wait, the "non-standard spacing" for the amp inputs that you complained about are both positive. Why would their spacing matter? Isn't the space between the mA and the common input what matters?
+ophello Yep, but visually it drives you nuts.
EEVblog lol
@5:05 please inline a link to episode #344. it'll save thousands of views the trouble of hunting around.
I thought a chipset was a set of chips, and not a single chip.
I got multimeter extech ma 1500 i got two one reads accurate voltage with tempe changes and other one roses and falls with tempe do you know what problem is
Just reading the posts and I'm thinking.....he did OK to remember where the 4 screws were he forgot about 4 years ago! Hmmm...
he says add some solder and the sub titles says that add some soda
Yeah, those times when Dave's a few screws short of a working multimeter...
I have a really cheap multimeter and the fuse blew on it, so I just soldered the the points together and it works.... but is that safe? I check AC and DC often but only need to see if there is power or not. Nothing specific.
+Matt Harden It's not safe. In certain circumstances an el cheapo multimeter can kill you even with fuses intact. Use a decent meter for mains measurement. For low voltages it is OK, you only kill the meter.
How did you get the schematic? I want to make my own Multimeter and I'd like examples to study
How do you get the schematics for all that stuff??
10mOhm current sense... Wow. My project ended up using both initial value and tempco compensation so no expensive component except maybe a bigger micro is required, but software work is outright tedious.
Wait, does a multimeter without an cold junction compensation only measure the temperature difference? So does a displayed 100 °C on such device in an 20 °C environment mean that the temperature is actually 120 °C?
Those without cold junction compensation typically assume the chassis/probe contacts will be at 25C (average room temperature, or thereabouts) and will indicate relative to that temperature. So, if you use the meter in an environment that is unusually hot or cold then it will be off by that amount. However, K-type thermocouples have a fair tolerance range so even if off by a few degrees they are still typically in spec, and they are often used to measure much hotter temperatures than ambient -- if you are measuring a 400C device and it comes back 410C because you are in a very cold room, you are still in the general ballpark in terms of your measured temperature. When you need more accurate readings you use a display that includes proper cold junction compensation by measuring the actual input terminal temperature. For more accurate thermocouple measurements, always allow time for the input terminals to reach equilibrium temperature after handing them.
Ok thank you for the explanation! That's completely clear. Some of the measurements I would do are not to far from room temperature, so I think I want compensation.
Dave, can you do a video on how LCR meters work? I would love to know how to make a good one using an Arduino.
I think it would be a very unique project since I have never seen one.
where are those links to the PDF schematics? I can't find any of this stuff on the Internet
PEBKAC...
Short between the earphones...
Nut loose on the keyboard...
My 87 v3 just displays all segments when powered up, rotary switch looks ok; cleaned contacts, think it could be the processor?.
Hi dave: I have to choose between Rigol DS1054Z (50Mhz, 4 channels), that would cost me 500$, and a used Tectronix TDS2024C (200Mhz, 4 channels) with a single probe that would cost me 600$, what would i choose, its my first oscilloscope, would you tell me why plz
Always good to show your mistakes.
Could you please explain a little more or give me a link for the ohm measurement of multimeters, I am trying to lear what is wrong with mine. Thank you for your video.
you should definitely go back and re-make some of your videos, like pock meter showdowns and such. things change over time.
hi brother, can you show me how to get drawing. i have some problem with my multimetter.
Hi there, love the vid - I'm sure you probably mention it in another video but what's your take on a Mastech? What are the chips/component layouts that drive it? Thanks.
The screws, screwed you over?
3:52
Why are you calling each IC a "chip set" and not just a "chip". Some meters have a 1 chip chip set, others have a 2 or more chip chip set right?
I got extech ma 1500 i sprayed it with contact cleaner electric spray and now it is fluctiating v with temp
The test leads weren’t pushed al the way in
You made my night! XD