EEVblog
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- เผยแพร่เมื่อ 18 ก.พ. 2016
- 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.
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.
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.
Great job Dave. Most people would delete the video. You turned it into a learning opportunity. Thumbs up.
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?)
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
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 ;-)
Hey EEVblog! I'm currently teaching myself electronics! I was inspired by my father and you :)
Very informative video. Thanks. Glad you didn't delete it.
Thank you for this great video Dave!! That was really enjoyable and educative. And also thanks to @Todd Harrison (ToddFun) for the contribution.
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.
Great video. I truly enjoyed it. Keep them coming.
I love how you didn't delete this video and actually made it into something useful.
This is why we watch your channel! :D
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.
3:52 Where's the FAIL button???
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.
Thanks, I'm, just learning about this stuff and the video helps.
I couldn't stop looking at the unpeeled factory screen protector. Ahh!
I guess the fluke needed to get screwed.. LOL Happens to the best of us mate. Great explanation - thank you
He thought it was going to be a problem, but it turned out to be a FLUKE. hahahah
great video. Can you do one for oscilloscopes? In particular how the acquisition circuitry and trigger works?
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
23:40
I must be tired, when Dave said "increase in value" I thought "really? The part gets more expensive?"
Awesome videos man, I learned a lot from them :)
The mark of a good performer. Something goes wrong, pick youreslf up and carry on. Thank you for being honest about the screws.
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
This is enlightening. I am thinking about creating my own multimeter design but I have to mix and match chipsets and microcontrollers.
Very good video
Great video, lots of clever design in there. What about the tempco of those trimmers? Gotta be bad!
Opps which then became a very interesting how to design a multi-meter. Thank you
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.
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.
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.
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 ?
where are those links to the PDF schematics? I can't find any of this stuff on the Internet
Where is the video about multimeter input protection mentioned at 11:20?
How do you get the schematics for all that stuff??
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!
LOL!!!!! That was great Dave Too funny you forgot the screews!
I wonder if Fluke would make a jig that auto tune the pots? Even more saving on top of saving $4 with cheap labor
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.
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!
Dave, please do the red pitaya vs analog discovery 2 comparison video!
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.
was it putting out the 3v test diode voltage i wonder
You made my night! XD
Its probably marketed as an HVAC dmm hence the temp accuracy.
Enjoy and learn much from your videos . I have an Snap On MT2400 graphing multimeter that registers around 3 volts without being connected to anything . Even with the leads out and new batteries . If I turn the backlight on the voltage increases . I'm new to and learning circuit boards . What possible problems could cause this ? Thank you for your time
At the beginning of this video, those probes are keysight/agilent?
Hey Dave. Are u making an eevblog meter? Thanks great videos
@5:05 please inline a link to episode #344. it'll save thousands of views the trouble of hunting around.
My 87 v3 just displays all segments when powered up, rotary switch looks ok; cleaned contacts, think it could be the processor?.
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.
How did you get the schematic? I want to make my own Multimeter and I'd like examples to study
this was... unexpected
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 :)
There's an EEVBlog multimeter? :o
Want!
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
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.
"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 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
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
5:53 can anyone tell me the specific name of that kind of chip. I used to see those circular chips when i was 10 years old on those toys that play a melody, I've always wondered the name of those IC because i have google it so many times with different names and nothing pops up
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....!
laugh abbaut yourself ;) this is what I like! ;) thanks for the video!
my father has a 19B he got from work it must be atleast 10 years old now and still works
9:18 - What is the purpose of Q1 and Q2?
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.
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)
I wouldn't have noticed the missing screws until already having replaced at least a capacitor.
Might be worth placing an annotation at ~16 minutes into #852. This may not be the pinnacle of multimeters, but it didn't fail.
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.
Had a good laugh. And at least you're honest.
Stupid silly mistake, everyone does it.
How do I get an EEVblog 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.
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!
16:53 you forgot about the fuses which may add up to 1 ohm on the path
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.
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.
Thumbs up for the screws! Love your videos. And as jorno1994 said: this was .... unexpected ;-)
Well at least Dave's streak of not being able to find anything repairable is gone. :D
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
The screws, screwed you over?
3:52
hi brother, can you show me how to get drawing. i have some problem with my multimetter.
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.
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
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
Yeah was excellent
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.
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...
ONE CHIP TO RULE THEM ALL !!! HAHA!! GOOD ONE :)
PEBKAC...
Short between the earphones...
Nut loose on the keyboard...
Is there a reason why multimeters nowadays dont come with li-on or li-po rechargeable batteries? Do such meters exist in the market?
Get a VICHY 99 like me. 1/20 of the price, and never had this sort of problem with it!
Just kiddin'. But seriouly, I own one.
Zip-A-Dee-Doo-Dah, wonderful feeling, wonderful day.
I got extech ma 1500 i sprayed it with contact cleaner electric spray and now it is fluctiating v with temp