Author Topic: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)  (Read 156195 times)

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Offline Lightages

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #150 on: February 07, 2015, 10:11:20 pm »
Modifying a multimeter with added MOVs or a spark gap does not make it safer, not necessarily. The design of the circuit board, the placement of the components, and the actual values are to be taken as a whole. It is possible that the current limiting resistors on the input jacks are not up to the task and putting an MOV in there is just adding a miniature bomb ready to go off if the current goes through it. I sincerely think that they aren't there as a cost cutting measure, but they could have been omitted to prevent a bigger problem that wasn't anticipated in the original design.

Labeling a meter with a specific safety rating incorrectly is wrong and no one can defend that. What is the harm? Well how about the person who is buying his first meter and watches some youtube video about meter ratings and sees that the UT71E is rated for CATIV 600V and then proceeds to use it on the meter connection to his house and gets seriously burned? This is not a problem? Sure the meter might be good value for the money, but only if you know that the ratings are a lie and know what you are buying.

No one can argue that meter with exactly the same specs is not a better meter if it has the correct CAT rating on it instead of a bogus one. No one can argue that a meter with a bogus rating is being sold truthfully. No one can argue that everyone has the time to take apart every meter on the market before they buy one and have them all tested individually for safety. That is what the standards are supposed to be for and why people die and get burned when they trust the CAT rating on a meter stuck on there by greedy assholes, culturally related or not. Thanks to off brand thieves and liars, people die. It is that simple.

That is why I started the thread about meters that don't appear to meet their CAT ratings, so that there was a reference and some guides for people to check. I have not updated it for a long time but it seems it needs to be again. How a sticky that is there for all to read with warnings about Uni-T meters has been missed, including by Dave, I don't know.

So Uni-T makes some shit meters, and some blatantly unsafe ones. DON"T BUY THEM. If they make safer ones, them buy them and send them a message that people don't want the bad ones. Unfortunately education and culture do play a part in this and where I live quality seems to be a joke and to ask for service is an insult. Mastech, Victor, Vichy, etc, all have deservedly bad reputations but then you get people here and other forums complaining about meter snobs who don't understand the needs of the less fortunate who don't have the money. Again what is the point of these discussions? EDUCATION. The poor and underprivileged need the same education so at least when the buy junk, they know, and they know the risks and limitations.

I have yet to see a Mastech I would recommend, nor a Vichy, most Digiteks no, and if I do recommend anything for anyone from the really budget class I make it a point to educate that the bogus CAT ratings are a joke and they should keep the probes out of the wall socket. Yes, not everyone has $100 to spend on a meter, some not even $50. This is exactly who needs to know what they are buying and why they need to be careful where they use it.

As far as the UT61E I had. It fried at 2500VDC. This was above the rated input but not above the impulse it is supposed to protect the user from. Maybe around 10mA passed through from the test and it caused nice sparks to jump around the selector dial. If it had been a 500A pulse the meter probably would have exploded. If you can see the spark at <10mA image the arc at 500A!!!

Again, say what you want about a meter having "value" even if it doesn't meet its safety rating. Go tell that to the people's friends and family who died in the story linked to earlier.

<Edited for grammar and spelling>
« Last Edit: February 07, 2015, 10:28:08 pm by Lightages »
 

Offline Quarlo Klobrigney

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #151 on: February 07, 2015, 10:30:51 pm »
You just about summed it up Lightages. Sounds about right to me.. :box: < It's a knockout!
« Last Edit: February 07, 2015, 10:41:03 pm by Quarlo Klobrigney »
Voltage, does not flow, nor does it go.
 

Offline Fungus

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #152 on: February 07, 2015, 10:35:11 pm »
Sure the meter might be good value for the money

But...that's the point. It isn't. $180 isn't a cheap meter by any standard. $180 for a meter where every single component is a cheap clone, several major design flaws, fake safety rating, marginal performance (the chip is a 20000 count device yet the meter claims 40000 count) isn't "good value". There are plenty of good meters at that price range, this one shouldn't be among them.

So Uni-T makes some shit meters, and some blatantly unsafe ones. DON"T BUY THEM. If they make safer ones, them buy them and send them a message that people don't want the bad ones.

Does it work like that? If people see other people using Uni-T meters they might assume it's a good brand. It isn't. The meter in this video was intentionally built to rip people off and make the maximum amount of profit. There's no other explanation IMHO.

« Last Edit: February 07, 2015, 10:38:21 pm by Fungus »
 

Offline Monkeh

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #153 on: February 07, 2015, 10:36:31 pm »
a meter where every single component is a cheap clone

Er, they are?

Quote
marginal performance (the chip is a 20000 count device yet the meter claims 40000 count)

No, the chip is a 44,000 count device.
 

Offline Fungus

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #154 on: February 07, 2015, 10:41:19 pm »
No, the chip is a 44,000 count device.

Watch the video again at time 17:15

 

Offline Monkeh

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #155 on: February 07, 2015, 10:42:55 pm »
No, the chip is a 44,000 count device.

Watch the video again at time 17:15

Watch the video again and look at the chip. Dave was wrong, it is an ES51966, which is a 44,000 count chip. It is clearly visible at 15:45.
 

Offline Fungus

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #156 on: February 07, 2015, 10:44:42 pm »
And let's not forget that Dave couldn't actually use the "Watts" function because they didn't supply the right plug for Australia.

(Probably just as well given the 1mm clearance between the input voltage line and GND. Would you connect it to something like a washing machine with a big motor?)

 

Offline Fungus

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #157 on: February 07, 2015, 10:45:31 pm »
Watch the video again and look at the chip. Dave was wrong, it is an ES51966, which is a 44,000 count chip. It is clearly visible at 15:45.

Ok, you win. I was just going by what the video said.
 

Offline Fungus

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #158 on: February 07, 2015, 10:54:23 pm »
a meter where every single component is a cheap clone

Er, they are?

Well, maybe not 100% of them. But far too many. When you're charging $180 the very least you could do is buy real part.

PS: I bet you're fun at parties...

 

Offline hamdi.tn

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #159 on: February 07, 2015, 11:07:07 pm »
some ppl gone too far with this killer meter , i used a Uni-t dirt cheap meter in main , in 3 phase main it work ok , and still alive  :phew:
i don't think that anyone here needed this video to actually be aware of how this meter quality is crap compared to any other high range brand, but again you know what you buying with your money, you know the risks related to it.
And i think some ppl here tend to forget that all of us started as hobbyist ... mean that you only have a limited amount of money to put it in one place, and a uni-t meter will surely be enough for the task and for the budget.
However lying about safety is certainly wrong and immoral, and they should correct that ...
 

Offline Fungus

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #160 on: February 07, 2015, 11:32:24 pm »
Value is all about matching price to expectations.

Would you not feel ripped off if you spent $180 on a meter then opened it up and saw what we saw in this video?




 

Offline sparx

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #161 on: February 07, 2015, 11:49:06 pm »
some ppl gone too far with this killer meter , i used a Uni-t dirt cheap meter in main , in 3 phase main it work ok , and still alive  :phew:
i don't think that anyone here needed this video to actually be aware of how this meter quality is crap compared to any other high range brand, but again you know what you buying with your money, you know the risks related to it.
And i think some ppl here tend to forget that all of us started as hobbyist ... mean that you only have a limited amount of money to put it in one place, and a uni-t meter will surely be enough for the task and for the budget.
However lying about safety is certainly wrong and immoral, and they should correct that ...

Just because you survived, doesn't mean that somebody else may connect it to 240v mains and it cause damage/injury/death.


Compare it to a vehicle, I get in my car and drive nearly every day. I'm sitting near enough on top of gallons of high power fuel with a relatively low flashpoint. I trust that the manufacturer has performed safety testing, and engineered in safety to the design. Same with the tyres and every other component.

When a manufacturer starts labelling equipment with markings/certifications which it does not have then they are undermiming those certifications/markings and what they mean, potentially resulting in future distrust in the markings as they will start to mean nothing! At least in that case I may be able to chase a global, massive, vehicle manufacturer for damages. I doubt you'd get a penny out of Uni-T.
 

Offline Nerull

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #162 on: February 08, 2015, 12:14:14 am »
Brymens are in the same price point, have almost all of the same features (except the near-useless watt range), and aren't built like shit.

No, a comparison between a Uni-T and a Gossen or brand-new Fluke isn't fair, but those aren't the only meters in the market. The Uni-T fails to compete with other meters in *its* price range.
 

Offline Leadfootin

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #163 on: February 08, 2015, 12:35:59 am »
If you want to know about our "safety rating" agencies, go to restorecsa.com which highlights some of the issues with CSA and it's ratings.

The articles will show you why not to trust any stated rating from one of these agencies.
 

Offline AlphZeta

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #164 on: February 08, 2015, 12:45:44 am »
For those who are not familiar with CAT rating requirements, from Wikipedia:

...The required values can vary from 0.04 mm for single insulation CAT II, 50 V, to 28 mm for double insulation CAT IV, 1000 V. The exact values are defined in the international standards.[1] Such standards should be followed rigorously during the design process of the appropriate equipment.

So yes, the fact it does not meet CAT IV standard is pretty clear.

But I wouldn't go so far as to discredit this meter altogether. Having the ability to measure power is one of its main selling point and most electricians only do mains related work and would not need an accuracy higher than 0.1 W.
 

Offline rageoftheblacksmith

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #165 on: February 08, 2015, 01:14:18 am »
Hello Dave and everybody else.
I'm writing here because i own a couple of UNI-T instruments but i am not a fanboy, neither am i trying to justify the money i spent on those things.

In the past i had to rely on a 830 and a 2905 chinese multimeters; i ain't posting pics because i suppose you all know what i am talking about.
In an emergency (woodworking workshop, very important machine stopped running) i had to search for the 400V 3-phase power with the 830; in another emergency i had to do the same (MIG welding machine) with the 2905. I was lucky, i'm still alive and both meters still pretend to work.

Back to recent times, my old no-brand LCR meter died and i wanted to replace it, so i went searching on ebay and i found this UNI-T LCR meter and i bought one.
When i got it in the mail i started testing it and i was pretty happy with it, the perceived quality was good so i decided to buy a multimeter from the same manufacturer and i got myself a 71D.

Unfortunately i wasn't on eevblog forum then and i found no information on UNI-T being bad; i can't afford a Fluke at the moment and i wonder if there is any intermediate segment between no-brand cheap shit, UNI-T down and The Real Instruments up. I thought i had a good deal with my UNI-T meters but now Dave says "don't buy that crap", more or less.

I've been thinking of buying an oscilloscope and, well, i would have gone for a UNI-T one but now i am not so sure.

Hope i wasn't boring you people, greetings and wishes,
rageoftheblacksmith.
 

Offline Lightages

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #166 on: February 08, 2015, 01:21:17 am »
There really needs to be a requirement here for people to state where they live before asking for any recommendations. This comes up over and over and over again. Where do you live? It is hard to tell you the best place to buy or what to buy if we have no idea where you are!
 

Offline rhdf

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #167 on: February 08, 2015, 01:32:43 am »
And that would likely be why Uni-T has no official distributors and meters are only available through third-party sellers on places like Amazon, Craigslist, eBay, etc.

If Uni-T had official ties outside China, that would expose them to lawsuits for wrongful death or injuries attributable to failure to meet their safety rating claims if there has been any.

Well, In Sweden they are sold by  At least 2 "big" chains. "Clas Ohlson", who sells some models as "UNI-T Clas Ohlson Edition" No idea whats special with that edition, but the package states "imported by Clas Ohlson".
The other one is "Kjell & Co" They seems to sell them "unbranded"
( non of them has the 71E model, only the 61D as "top model") But ~600 SEK is "OK" for hobbyists instead of the cheapest FLUKE for double the price
 

Online AG6QR

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #168 on: February 08, 2015, 01:36:16 am »
I've got an older Triplett meter (1101) which has engraved in the plastic case "NOT FOR USE ON HIGH ENERGY CIRCUITS".  It has a glass fuse inside, lacks proper input protection to pass CAT standards, but it meets my expectations.  It is what it is, and like Dave's first Micronta meter that he displayed in the Radio Shack video, it is capable of safely doing useful work within its limitations.

The UNI-T, on the other hand, clearly claims it meets CAT standards, but it doesn't.  The circuit board looks like it was even designed to hold proper fuses, but assembled without them.  The company obviously made a conscious decision to cut costs at the expense of safety, and they did it while maintaining the claim on the front of the meter that it meets CAT standards.  And they package the meter with the device to invite you to plug it into mains.

That's slimy and untrustworthy.  If I can't trust the company behind the meter, I won't really trust the readings from the meter.
 

Offline rolycat

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #169 on: February 08, 2015, 01:37:01 am »
There really needs to be a requirement here for people to state where they live before asking for any recommendations. This comes up over and over and over again. Where do you live? It is hard to tell you the best place to buy or what to buy if we have no idea where you are!
A poll a year ago showed a substantial majority in favour of requiring users to specify a country during registration. This can be a 'black flag' for those paranoid about revealing personal information on the net.

However, Dave does not appear keen.
 

Offline DanielS

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #170 on: February 08, 2015, 01:39:45 am »
Value is all about matching price to expectations.

Would you not feel ripped off if you spent $180 on a meter then opened it up and saw what we saw in this video?
Although it was not really a variable in my purchase decision for my UT61E, I certainly would not be happy that a device clearly labeled as Cat-IV like the 71E might only meet Cat-II and only up to 250V. Intentionally misleading people into believing the device is much safer than it actually is certainly does not earn positive marks from me and should not earn any from anyone.

If you are going to design a piece of equipment that only meets 250V Cat-II safety, do the world a favor and mark it as 250V Cat-II before you kill someone.
 

Offline rageoftheblacksmith

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #171 on: February 08, 2015, 01:40:32 am »
Where do you live? It is hard to tell you the best place to buy or what to buy if we have no idea where you are!

Sorry, Lightages, i didn't think that my location was important. I live in Italy and most of the chinese stuff i buy online comes either from Hong Kong or from stocks in the UK.
I wouldn't buy anything from the U.S.A. because stuff coming from there always seems to be involved in customs trouble.
Should i ever decide to buy a Fluke there should be no problem because they are supposed to be made in Germany, right?
 

Offline Yago

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #172 on: February 08, 2015, 01:47:33 am »
I'll say it again eh?
Brymen meters if you are in EU.

There's a few places to get them, TME, and our own Lightages or Franky(Iloveelectronics)
 


Offline rageoftheblacksmith

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Re: EEVblog #712 - Uni-T UT71E Multimeter (Why Uni-T Meters Suck)
« Reply #174 on: February 08, 2015, 02:11:04 am »
Thank you Yago and Lightages for the information.
 


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