Author Topic: UNI-T UT61E Multimeter teardown photos.  (Read 719339 times)

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Offline Hydrawerk

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #925 on: May 20, 2016, 08:30:26 pm »
The bargraph disappears and appears again. This is weird.
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Offline nyarvin

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #926 on: July 16, 2016, 04:16:10 pm »
One thing to note about the new PCB layout, as regards adding protection elements: there are four places to add MOVs (or gas discharge tubes), but the way they are connected is not simply as shunts to ground.  Instead, one of them shunts to ground and then the other three connect to it.  So if you just stick one-kilovolt MOVs in all of them, they may not fire until the input reaches two kilovolts.  Instead, for a kilovolt of protection, use 500V MOVs everywhere, or three one-kilovolt MOVs plus a jumper in the fourth place.

Also, besides those four places, there's another unpopulated space for a MOV near the current-measuring stuff.
 

Online joeqsmith

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #927 on: September 01, 2016, 01:07:59 am »
I picked up a brand new UT61E.   It appears identical to the one 5KY had sent.   Metal can and all.   

So, what I would like to do if modify this meter with the MOVs people are recommending, or use the parts that are available in the one being supplied to Germany.   I will then retest it to failure and see if there are any improvements. 

Keep in mind the 61E and D never made it to the mini surge test.  They both failed ESD with that little grill starter.   

Offline jarvis

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #928 on: September 01, 2016, 08:25:07 am »
The bargraph disappears and appears again. This is weird.

The bar-graph is shown by the measurement time counting down for mF range of CAP.
It is indicated in datasheet of ES51922 chip.
 

Offline MosherIV

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #929 on: September 01, 2016, 08:30:25 am »
Hi

Quote
So, what I would like to do if modify this meter with the MOVs people are recommending, or use the parts that are available in the one being supplied to Germany.   I will then retest it to failure and see if there are any improvements.

Look at this thread
https://www.eevblog.com/forum/testgear/varistormov-for-ut61e/

I have just got these
http://cpc.farnell.com/epcos/b72210s0381k101/varistor-40-0j-385vac/dp/RE03689
to fit in mine. Have not fitted them yet, I want to check the capacitance measurement before and after - I will only have access to a LCR bridge at the weekend to check the 1% caps, that I just bought, against the meter readings.

These
http://cpc.farnell.com/epcos/b72214s0321k101/varistor-84-0j-320vac/dp/RE03698
Will give you a lower clamp voltage but not give you the full 1000V DC spec
 

Online joeqsmith

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #930 on: September 02, 2016, 01:59:22 am »
Hey, I remember your other thread and was hoping you would have tried them out by now.  I'm in no rush so take your time and post your results on the capacitance.   Hard to believe it would be a problem as you zero it out anyway.     

Hi

Quote
So, what I would like to do if modify this meter with the MOVs people are recommending, or use the parts that are available in the one being supplied to Germany.   I will then retest it to failure and see if there are any improvements.

Look at this thread
https://www.eevblog.com/forum/testgear/varistormov-for-ut61e/

I have just got these
http://cpc.farnell.com/epcos/b72210s0381k101/varistor-40-0j-385vac/dp/RE03689
to fit in mine. Have not fitted them yet, I want to check the capacitance measurement before and after - I will only have access to a LCR bridge at the weekend to check the 1% caps, that I just bought, against the meter readings.

These
http://cpc.farnell.com/epcos/b72214s0321k101/varistor-84-0j-320vac/dp/RE03698
Will give you a lower clamp voltage but not give you the full 1000V DC spec

Offline exxocet

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #931 on: October 05, 2016, 09:16:28 am »
Hey guys,
  I've got my UT61E back in 2010, way before it became the star of the affordable DMM show. :D  Gotta be one of the first PCB layouts, there were no EU versions back then. Input protection is really basic, no safe-cut board on the PTC, no resistor area shielding, but hey, it's a great DMM if you're not dealing with industrial voltages/currents, as most of us never do. It served me like a hero and it still works damn well, but... what's that bridge on capcitors C9a and C9b? Is this a soldering fault or it's the default design on this early PCB version?
  Maybe someone with a similar PCB would help with a picture of his own layout. Thank you.
 
 

Online joeqsmith

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #932 on: October 05, 2016, 05:34:34 pm »
Hey guys,
  I've got my UT61E back in 2010, way before it became the star of the affordable DMM show. :D  Gotta be one of the first PCB layouts, there were no EU versions back then. Input protection is really basic, no safe-cut board on the PTC, no resistor area shielding, but hey, it's a great DMM if you're not dealing with industrial voltages/currents, as most of us never do. It served me like a hero and it still works damn well, but... what's that bridge on capcitors C9a and C9b? Is this a soldering fault or it's the default design on this early PCB version?
  Maybe someone with a similar PCB would help with a picture of his own layout. Thank you.
 

I would wager I could kill a brand new UT61E without anything more than the dry winter air,  the carpet in my office,  my metal desk and my hands.  Sounds real industrial.   :-DD   

My guess is C9a/b are in parallel and one is hand selected and soldered as a cheap way to trim this part of the circuit.
 
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Offline exxocet

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #933 on: October 05, 2016, 06:02:25 pm »
 
Quote

I would wager I could kill a brand new UT61E without anything more than the dry winter air,  the carpet in my office,  my metal desk and my hands.  Sounds real industrial.   :-DD   

My guess is C9a/b are in parallel and one is hand selected and soldered as a cheap way to trim this part of the circuit.

  Yeah, while all the other components look industrially soldered (you like that, ah? ;D ), it's always C9 that seems hand soldered. Badly soldered.
  PS: I've re-soldered those schmucks and C9a is in fact two capacitors, one on top of the other.
« Last Edit: October 05, 2016, 06:42:17 pm by exxocet »
 

Online joeqsmith

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #934 on: October 05, 2016, 10:17:24 pm »
I do like the 
Quote
it's a great DMM if you're not dealing with industrial voltages/currents, as most of us never do.
.    I understand that lack of robustness may be considered a desired trait as the meter being damaged easily provides the user with an indication that their meter was exposed to something that may cause it to fail later on.   For these people, it will be hard to beat the UNI-T brand!!   :-DD

So three capacitors in parallel?   This sort of makes sense.  Labor is cheap.  Start with the large part, add trimmer one, then a fine trim.  Does not look great but gets the job done. 





Offline exxocet

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #935 on: October 06, 2016, 06:26:11 am »
I do like the 
Quote
it's a great DMM if you're not dealing with industrial voltages/currents, as most of us never do.
.    I understand that lack of robustness may be considered a desired trait as the meter being damaged easily provides the user with an indication that their meter was exposed to something that may cause it to fail later on.   For these people, it will be hard to beat the UNI-T brand!!   :-DD

So three capacitors in parallel?   This sort of makes sense.  Labor is cheap.  Start with the large part, add trimmer one, then a fine trim.  Does not look great but gets the job done.

  A DMM that pass your test (by the way, awesome job) it's great DMM? No, it's safe DMM. It plays well outside of it's specs. That safe meter may measure 10.7v on a 10v reference source and that makes it a shit DMM, even if it's safe. Why? Simply because it's not doing what it was designed to do.
  UT61E it's a $50 meter that does most of what $500 Fluke does. Now I know that Americans have a fetish for Fluke, but there are hobbyist that don't afford to pay $500 for a DMM, while they don't make any money from it. Oh, you run a business or your incoming allows? Go for Fluke, it's a reliable and rock solid meter. But I tell you, it's still way overpriced. Cool PCB alignment, fine soldering and adequate V/A protection still don't make for 10 times the price of the Chinese meter.

  Anyway, you're right here, cheap DMM shouln't be cheap on security, especially on input protection. I mean, it's so easy to design a proper one and won't add more that $0.5 on the  production cost, but what you gonna do... guess that's the Shenzhen way.
« Last Edit: October 06, 2016, 06:38:57 am by exxocet »
 

Offline ProBang2

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #936 on: October 06, 2016, 06:51:46 am »
Now I know that Americans have a fetish for Fluke

Honestly, you can´t joeqsmith call a fanboy of Fluke. At least not for the 87V.
He obviously prefer the Brymen869. A DMM outperforms the Fluke87V in CAT-Ratings (Cat IV 1000V versus CAT IV 600V) and some other functions for half the price...
« Last Edit: October 06, 2016, 06:54:29 am by ProBang2 »
 

Offline exxocet

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #937 on: October 06, 2016, 11:23:42 am »
  I'm not talking specifically about joeqsmith. He is a pro, he knows his equipment and use what's the most efficient for his job. Doesn't really matter if the DMM costs $200 or $500 as long as it's a tool to perform your profession.
  I'm talking about the joe-q-average, that use a DMM for hobby or occasional works. You don't make money from using that DMM, you pay money to enjoy your hobby. Why would you pay $500 for a tool that should cost at most $300, including the "Fluke brand name aura"? You're right, it's twice as much as it should be. Anyway, guess I'm offtopic, back to our little chinese friend.
 

Online joeqsmith

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #938 on: October 06, 2016, 01:17:21 pm »
  A DMM that pass your test (by the way, awesome job) it's great DMM? No, it's safe DMM. It plays well outside of it's specs.

  :horse:  :-DD  Dead horse with and a parrot would have been my choice.   I wonder how much of the confusion comes from the language.  So to be clear, you feel if a meter survives with transient that has 10 to 20 Joules available that means it's safe?

Pretty much all the meters I look at are CAT III 600V rated per IEC 61010.  That's the spec.  Now what that means as far as their ability to survive the transients I supply is up for grabs. 

That safe meter may measure 10.7v on a 10v reference source and that makes it a shit DMM, even if it's safe. Why? Simply because it's not doing what it was designed to do.

Yea, if you bought a meter that was spec'ed this loose, that's on you.  If the meter is outside it's spec'ed accuracy and it was shipped to you this way, you may want to return it.   Most of the meters I have looked at work when they arrive and are in spec.  The last CEM I looked at and the free meters we get from Harbor Freight were dead out of the box.  Pretty rare.   

UT61E it's a $50 meter that does most of what $500 Fluke does. Now I know that Americans have a fetish for Fluke, but there are hobbyist that don't afford to pay $500 for a DMM, while they don't make any money from it.
Oh, you run a business or your incoming allows? Go for Fluke, it's a reliable and rock solid meter. But I tell you, it's still way overpriced. Cool PCB alignment, fine soldering and adequate V/A protection still don't make for 10 times the price of the Chinese meter.

  Anyway, you're right here, cheap DMM shouln't be cheap on security, especially on input protection. I mean, it's so easy to design a proper one and won't add more that $0.5 on the  production cost, but what you gonna do... guess that's the Shenzhen way.

The UT61E is pretty low end but you are right, the Fluke 101 does not have a backlight just like the 61E.   :-DD  And sure, you touch it wrong and static zap it, it may very well suffer permanent damage.  And sure it's not certified to meet the safety or EMC standards.   Sure, it is supplied with crap fuses....

It would be interesting to see some data showing handheld meter purchases in the USA by OEM and cost.  I really have no idea.  I doubt Fluke is the brand that the average person finds at the hardware store. 
 
Again, for my normal use where I need a handheld I still use $50 meters.  But my $50 meter can take some basic ESD.  I also have a backlight, which I use.   This is mostly for working on cars, bikes and such.  So I just don't need much for a meter. 

I really don't know what it would cost UNI-T to roll a better version of the 61E that passes both the EMC and safety standards and maybe adds a backlight.  I did not have a 61E at the time I did the temperature drift study but I hear it is pretty bad.  Maybe improve this as well.    The cost of scrap, new layout, parts, setup, testing, certification... How many they sell...   Yea, I have no idea.  The GS version looks to me more like $20 - $40 higher, not $0.50.     




Offline igi

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #939 on: October 12, 2016, 08:38:13 am »
Guys, I killed my brand new UT-61E. Tried to measure voltage on a microwave transformer and device turned off forever. Yes, that was dumb, I know. But any chance to get it back? Can't justify myself to throw new shiny device into a trash bin. Nothing happens when I rotate the dial, screen remains off. Battery is fine. I see no visible damage to internals. The only thing happening inside is W1 (linear voltage regulator 7201U30 is becoming warm). I desoldered and checked this LDO and it works fine itself. So i guess there is some kind of short circuit somewhere down the road. Any hope it is not a main chip? Should I check something else? The schematics of the device is a bit too complex for me, I am a newbie. Thanks!
 

Offline setq

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #940 on: October 12, 2016, 10:22:58 am »
Doh. I think that'd blow up a lot of things. I'd chuck it and buy another one.

As for safety, I've got a UT61E. It occasionally gets stuck across the mains. If it blows up, it blows up. I'll just buy another one.  I'd have to buy 8 of them before I caught up with a Fluke's pricing. If I'm going to kill myself it is more likely due to human error, probing errors etc than anything to do with the meter exploding. Daily use it sees 5mV-300v DC.

However going back not so far ago, the status quo of meters was far more dangerous than a UT61E. Even a relatively recent 1980s FET based meter from a respectable brand I saw had a negative terminal connected to the chassis and a non-earthed supply. Stuff that across the mains and things get interesting.

Most of the fluff that Fluke point out about safety isn't relevant or useful to the average user.
« Last Edit: October 12, 2016, 10:24:29 am by setq »
 

Offline MosherIV

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #941 on: October 12, 2016, 01:41:14 pm »
Quote
Guys, I killed my brand new UT-61E. Tried to measure voltage on a microwave transformer and device turned off forever. Yes, that was dumb, I know. But any chance to get it back? Nothing happens when I rotate the dial, screen remains off. Battery is fine. I see no visible damage to internals. The only thing happening inside is W1 (linear voltage regulator 7201U30 is becoming warm). I desoldered and checked this LDO and it works fine itself. So i guess there is some kind of short circuit somewhere down the road. Any hope it is not a main chip? Should I check something else? The schematics of the device is a bit too complex for me, I am a newbie. Thanks!
It sounds like you have blown the main chip. Without the MOVs in place there was no chance of the input protection stopping KV, even with them fitted joeqsmith proved they can be inadequate.
The main chip is not obtainable, the chip manufacturer does not sell on the open market.

Salvage what you can and get a new DMM. Most DMM are not capable of measuring thousands of V (KV) - do no attempt it again unless you like spending money on DMMs  ::)
 

Online joeqsmith

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #942 on: October 12, 2016, 10:10:01 pm »
Can't justify myself to throw new shiny device into a trash bin.

I wouldn't.  Driving over it, throwing it out the car window, dropping it from 3 or 4 stories and shooting it with an arrow are all little overdone.  Make a video of what you come up with.

Offline Hydrawerk

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #943 on: October 16, 2016, 11:12:03 pm »
Tried to measure voltage on a microwave transformer and device turned off forever.
I think that even Brymen BM869 will be damaged by 2000V 500mA or so. Hardly any DMM can handle 2000V for a long time.  :(
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Offline analogix

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #944 on: October 21, 2016, 09:10:59 am »
My old multimeter has finally given in and it seems the UT61E is the way to go (this is for hobby use -mostly measuring low voltage stuff and the occasional AC household (230V) measurements).

Have the safety issues been resolved with the currently available UT61E?
Where's the best place to order it from these days?
Apparently, the "GS" European version isn't available from the many Chinese low cost sources but through various German dealers such as Pinsonne-elektronik (75 Euros). But confusingly many Chinese dealers sometimes show a mix of the "GS" and "China" version of the unit along with USB and serial cables, and if you ask them about it they seem to tell you what they think you want to hear and really have no clue other than to shift as many cardboard boxes around as they can!

So, if I don't want to pay the much higher "GS version" costs, where's a good place to get it?
(of course, if some low cost Chinese dealer does have the actual "GS" version for sale cheaper than buying it from a dealer in Europe I'll definitely be going for that instead).

And does the current version now come with a USB cable or is this also a random thing?
« Last Edit: October 21, 2016, 11:00:01 am by analogix »
 

Offline Loboscope

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #945 on: October 21, 2016, 10:12:10 am »
I bought my UT61E from "pinsonne-elektronik.de", it was shipped immediately. It came with USB-Connection and of course it was the official "GS"-version.
So I can recommend "pinsonne-elektronik".
 

Offline analogix

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #946 on: October 21, 2016, 11:02:38 am »
Sounds like a good place to order from, even though the price will be higher than with the Chinese version.
Unfortunately, although Pinsonne-elektronik will send to Sweden and Denmark, Norway isn't listed  :(
I'll keep on searching, and if the total price will be too high I'll probably go for the Chinese version instead -suggestions to where I should get it from?

Offline MosherIV

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #947 on: October 21, 2016, 11:05:54 am »
I bought mine from Amazon. They have a 'market place' so there were 4 or 5 vendors offering UT61E.
The advantage of Amazon is that they provide the seller vetting and should sort out any disputes with the seller,
I have not had any trouble with my UT61E (hopefully never will).
I do not remember which vendor I chose.
 

Offline setq

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #948 on: October 21, 2016, 12:22:13 pm »
For ref, mine was seller "emma2103dw" £35.99 inc delivery. Drop shipping op. Arrived in 3 days RM 2nd class no problems at all.

Gubbins and input protection in my variant:



No problems either.
 

Offline analogix

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Re: UNI-T UT61E Multimeter teardown photos.
« Reply #949 on: October 23, 2016, 09:51:59 am »
For ref, mine was seller "emma2103dw" £35.99 inc delivery. Drop shipping op. Arrived in 3 days RM 2nd class no problems at all.

Is this on eBay, Amazon or some other place? I haven't been able to find it.
It appears that I have to pay quite a lot more than that if I want the "GS" version, so in that case I might as well buy a more expensive meter, buy a UT61D locally (they're about US$ 75/EUR 74/GBP 65) which is GS marked and comes with both USB and serial cables (which when I think about it really doesn't matter anyway as I'm on a Mac and all that software is Windows only).
But that's the Chinese (non-GS) version you have there, right?
And as far as I know, none of the Chinese versions come with USB cables -but if I'm not mistaken the actual meter is the same, and it's just a matter of attaching a USB cable or serial cable, right? There's no actual "USB version" or "serial version" of the multimeter, is there?
« Last Edit: October 23, 2016, 09:58:02 am by analogix »
 


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