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How many cycles will the KeySight U1281A's detent spring last?

0-2000
7 (17.9%)
2k-4k
5 (12.8%)
4k-8k
14 (35.9%)
8k-16k
7 (17.9%)
>16k (most rubust meter ever made)
6 (15.4%)

Total Members Voted: 36

Author Topic: Handheld meter robustness testing  (Read 1149339 times)

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Offline cybercorfu

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Re: Handheld meter robustness testing
« Reply #4350 on: January 11, 2022, 07:38:36 pm »
Its used bought it from ebay I cut positive cable from battery and made the measurement
 

Offline joeqsmithTopic starter

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Re: Handheld meter robustness testing
« Reply #4351 on: January 12, 2022, 01:47:00 pm »
When I measured the battery life, I think I just clipped onto the meters connector.   

Offline cybercorfu

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Re: Handheld meter robustness testing
« Reply #4352 on: January 12, 2022, 11:06:12 pm »
Is it possible for a faulty MOSFET ?  It really annoying not using the meter and trying to power it on and needs changing
 

Offline joeqsmithTopic starter

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Re: Handheld meter robustness testing
« Reply #4353 on: January 13, 2022, 12:21:41 am »
You would need to trace that section out and track down the high leakage path.   I had started to look at that area after I damaged mine.   It seemed to use all jellybean parts so shouldn't be too difficult to repair.   With that being a weak area, I wonder if yours was subjected to a small transient as well. 

Offline cybercorfu

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Re: Handheld meter robustness testing
« Reply #4354 on: January 13, 2022, 11:42:14 pm »
Remove AIQ5VA IC and the current dropped to 1mA I've made an order and we see... I think maybe ever make an external charging port straight to battery with a protection circuit for logging perposes and drop the whole IC for charging unable to use meter...
 

Offline cybercorfu

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Re: Handheld meter robustness testing
« Reply #4355 on: January 14, 2022, 08:41:02 am »
It does seem high a few μA OK but a mA it high
 

Offline AVGresponding

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Re: Handheld meter robustness testing
« Reply #4356 on: January 14, 2022, 10:42:43 am »
Doesn't a mA seem high?

Especially when you consider the shunt resistance... take that out of circuit and it's going to be even higher.
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Offline joeqsmithTopic starter

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Re: Handheld meter robustness testing
« Reply #4357 on: January 14, 2022, 11:42:17 am »
Doesn't a mA seem high?

Especially when you consider the shunt resistance... take that out of circuit and it's going to be even higher.
Sure, the current most likely would get higher but is it really worth pointing out?    I had asked them how they measured the current but not being there, I really have no idea outside of the cut wire.   I don't know anything about the circuit but it could very well be acting as a constant current sink.   They would need to supply more data.  Still it's a 7ish volt battery.  Even with a 100 ohms, at a mA your talking 100mV of drop.   Under a percent error.  I would think they would be using an amplified shunt without a fuse but who knows. 

Offline cybercorfu

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Re: Handheld meter robustness testing
« Reply #4358 on: January 14, 2022, 01:49:51 pm »
Under constant observation the current leakage stabilized at 95μA maybe its the RTC and XTAL that's fine I guess...
 

Offline joeqsmithTopic starter

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Re: Handheld meter robustness testing
« Reply #4359 on: January 14, 2022, 03:10:28 pm »
Under constant observation the current leakage stabilized at 95μA maybe its the RTC and XTAL that's fine I guess...

I'll measure mine when I have some time today and let you know.  While mine was damage, later repaired and then modified, I doubt there was any effect on the current draw.   Should at least provide you with some idea how low it should be.   As I said, mine will sit for months at a time and not discharge. 

Online Grandchuck

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Re: Handheld meter robustness testing
« Reply #4360 on: January 14, 2022, 03:17:21 pm »
Under constant observation the current leakage stabilized at 95μA maybe its the RTC and XTAL that's fine I guess...

As I said, mine will sit for months at a time and not discharge.

Same here.
 

Offline joeqsmithTopic starter

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Re: Handheld meter robustness testing
« Reply #4361 on: January 15, 2022, 12:06:27 am »
I measure about 37.4uA with 7.5V.   
 
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Offline ilkinandr92

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Re: Handheld meter robustness testing
« Reply #4362 on: January 22, 2022, 07:14:54 am »
Another option,  start with the grill starter, kill it in a few seconds and leave it at that....  Nice short video, right to the point.   :-DD :-DD

Correct.

I mean, seriously, what is the point of testing the UT61E for "robustness"? We all know it isn't.
At first glance yes. The UT61E (and probably the UT61E+) are finicky with transients but why not put it through its paces? Who knows? Perhaps it could be an additional advantage of the "plus" model...

Looking at the data I've collected,  of the eight UNI-T products I looked at, half never made it past the ESD, AC line tests.    During the EEVBLOG review for the 61E+, Dave focuses on the lack of a surge rated resistor.   The UT181A is the same and survived some decent hits after a few small changes.    Dave talks about the new ground path.   It could help but my guess is it won't.   

Obviously that the "real" test would be with the "third party plus-certified and mega-accredited and über-listed" UT161E, but that is in another price league...

That meter would fail ESD just like the stripped down version.   

At any rate, I don't think there is much to be lost, especially after you already beaten to death the UT61E original, with excellent suggestions to increase its robustness.

For you, skim the video for a few seconds and your done.    Flip side, it takes fair amount of my time to run the tests and edit the videos.  For this meter, assuming the grill starter kills it, maybe six days.   Half of that would be cycling the function switch.   
 

(edit) Kerry Wong also did a teardown of the UT61E+
http://www.kerrywong.com/2021/04/04/teardown-of-a-uni-t-ut61e-true-rms-multimeter/

(edit2) Tenma has some discounts on beefed up UT61E (non plus)
https://www.eevblog.com/forum/buysellwanted/newark-sale-on-many-tenma-brand-meters/msg3655997/

Skimmed the Kerry Wong video but didn't notice anything beyond what Dave had gone over. 

We could reorder the tests for this special meter.  Start with the 100us transients.  If it survives  that (which it won't) then run the AC line test and then the ESD.  Not sure we would learn anything more doing this.  The end results the same. 

UNI-T fanboys are already thinking I am biased against this meter.  I can see the mass of down votes. lol.  I have more than enough data now to know what to expect.

Hi,
I know this is reopening an old topic, but I would love to see how UT161E would fair in your tests.
I was able to find a video of UNI-T UT161E and UNI-T UT61E+ that shows some differences.
He mentions that there is some modification at the top part of the PCB.

https://www.aliexpress.com/item/1005002717433552.html?spm=a2g0s.8937460.0.0.73f02e0eghZUfO
 

Offline Fungus

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Re: Handheld meter robustness testing
« Reply #4363 on: January 22, 2022, 08:18:07 am »
Hi,
I know this is reopening an old topic, but I would love to see how UT161E would fair in your tests.

Why? If robustness is a big concern then you can buy a proper multimeter for that much money.

 

Offline joeqsmithTopic starter

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Re: Handheld meter robustness testing
« Reply #4364 on: January 22, 2022, 03:23:02 pm »
https://www.uni-trend.com/meters/html/product/General_Meters/Digital_Multimeters/UT61%20161%20Series/UT161E.html

Frequency (Hz)    220MHz    ±(0.01%+5)

Note the lack of anything to limit the current if I attempt it.  I suspect we would see another meltdown if I were to attempt to test this feature.     Of course, we could just ignore it like the UNI-T fan boys suggested.   

Skimming the video, they have larger fuses which makes no difference in the data I collect.  The voltage path looks the same.  After damaging its little brother, I beefed up the clamp.   This meter wouldn't have that luxury and would most likely not hold up as well.   



That channel is getting close to 20k subscribers.  Like when it hit 2k, it seems like we should have a look at something special if it ever makes it up that high.   Last time we had a lot of fun with a high end Gossen.   

Offline ilkinandr92

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Re: Handheld meter robustness testing
« Reply #4365 on: January 22, 2022, 10:47:18 pm »
Hi,
I know this is reopening an old topic, but I would love to see how UT161E would fair in your tests.

Why? If robustness is a big concern then you can buy a proper multimeter for that much money.

161E goes on sale for $56 at times, if you can recommend anything better that has same features or more I'm open to suggestions.
 I am not electrician, I am just looking to get something that is best bang for the buck and the better the protection the better. I only plan to use it for anything as small electronics to 240v 3 phase machines my dad has at his shop.
My other option is Brymen BM789 but I didnt want to spend that much and not sure how the warranty would even work on it, when its imported to US.
 

Offline joeqsmithTopic starter

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Re: Handheld meter robustness testing
« Reply #4366 on: January 22, 2022, 11:50:51 pm »
And how does the warranty work on the UNI-T in the USA?   

Offline rsjsouza

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Re: Handheld meter robustness testing
« Reply #4367 on: January 23, 2022, 01:15:15 am »
And how does the warranty work on the UNI-T in the USA?
You can get warranty in the US for a "Uni-T like" by paying a steep premium from Farnell:
https://www.newark.com/multicomp-pro/mp730679/dmm-true-rms-20a-1kv-22000-count/dp/64AJ4559?st=Tenma%20multimeter

Terribly expensive for what it is. Even their old UT61E models do not have the promotional price anymore.
https://www.newark.com/tenma/72-10415/dmm-hh-10a-1kv-22000count/dp/94AC6580?st=Tenma%20multimeter

My other option is Brymen BM789 but I didnt want to spend that much and not sure how the warranty would even work on it, when its imported to US.
As for Brymen in the US with warranty, Greenlee would be the brand to go. They don't have a BM789, but a BM869 instead. Paying a bit more than the originals, but it is the real deal. I just got a brand new DM200A (BM251S) on an eBay bargain (half of a UT61E+) and it is incredibly compact and well built, even features premium gold leads. :-+
« Last Edit: January 23, 2022, 01:16:46 am by rsjsouza »
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Offline ilkinandr92

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Re: Handheld meter robustness testing
« Reply #4368 on: January 23, 2022, 01:45:39 am »
And how does the warranty work on the UNI-T in the USA?
You can get warranty in the US for a "Uni-T like" by paying a steep premium from Farnell:
https://www.newark.com/multicomp-pro/mp730679/dmm-true-rms-20a-1kv-22000-count/dp/64AJ4559?st=Tenma%20multimeter

Terribly expensive for what it is. Even their old UT61E models do not have the promotional price anymore.
https://www.newark.com/tenma/72-10415/dmm-hh-10a-1kv-22000count/dp/94AC6580?st=Tenma%20multimeter

My other option is Brymen BM789 but I didnt want to spend that much and not sure how the warranty would even work on it, when its imported to US.
As for Brymen in the US with warranty, Greenlee would be the brand to go. They don't have a BM789, but a BM869 instead. Paying a bit more than the originals, but it is the real deal. I just got a brand new DM200A (BM251S) on an eBay bargain (half of a UT61E+) and it is incredibly compact and well built, even features premium gold leads. :-+

I wouldn't care much about 161e warranty for $50-60 price.
I was looking at BM869s but it's too bulky and expensive than even 789. DM200A Looks nice but limited features and small counter.
Got anything close to 161e feature wise, better protection around $100?
If not, would 161e be safe while working on 240v 3 phase machines? I would mod it to make it more robust but not electrical engineer, and I know it's not allowed to ask for help with that here sadly.
Appreciate the help.
 

Offline Fungus

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Re: Handheld meter robustness testing
« Reply #4369 on: January 23, 2022, 07:26:17 am »
Got anything close to 161e feature wise, better protection around $100?

For that money you can get a decent Zoyi and a Fluke 101. Two meters is always more useful than one and you can poke at your mains power with the Fluke.

The only excuse I can think of for buying that Uni-T is the PC data connection. Nothing else about it says "This is worth the money!" (IMHO).

161E goes on sale for $56 at times, if you can recommend anything better that has same features or more I'm open to suggestions.

If you really want the Unit-T then get one at that price plus a Fluke 101. For the same reasons given above.
« Last Edit: January 23, 2022, 07:28:58 am by Fungus »
 

Offline Fungus

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Re: Handheld meter robustness testing
« Reply #4370 on: January 23, 2022, 07:50:43 am »
If not, would 161e be safe while working on 240v 3 phase machines?

No meter is 100% "safe" because there's always operator error. There's also a couple of pages now that are telling you that it's probably no better than the ordinary 61E, ie. the extra '1'  in the name is mostly marketing.fluff to sell (practically) the same meter for more money.

The Fluke 101 is about as close as any meter gets to "safe" in untrained hands.
 

Offline ilkinandr92

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Re: Handheld meter robustness testing
« Reply #4371 on: January 23, 2022, 08:15:25 am »
If not, would 161e be safe while working on 240v 3 phase machines?

No meter is 100% "safe" because there's always operator error. There's also a couple of pages now that are telling you that it's probably no better than the ordinary 61E, ie. the extra '1'  in the name is mostly marketing.fluff to sell (practically) the same meter for more money.

The Fluke 101 is about as close as any meter gets to "safe" in untrained hands.
161 does have better fuses than 61E+. But I understand that nothing is 100% safe. I'm just saying I don't want it blowing up in my hands from that voltage.
I'm not a fan of carrying multiple multimeters, I guess ill just save up for BRYMEN BM789.
Anyone know of good place to get one in US or selling theirs?
« Last Edit: January 23, 2022, 08:18:22 am by ilkinandr92 »
 

Offline Fungus

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Re: Handheld meter robustness testing
« Reply #4372 on: January 23, 2022, 08:41:19 am »
161 does have better fuses than 61E+.

The fuses only come into play when the cable is in the amps socket. Hopefully you'd never be poking at the 240V machines with the cable in that position so the difference in fuses is moot.

(nb. Joe doesn't do any tests on amps ranges)

For most "safety" situations the missing surge resistor is what counts, not the fuses, and that resistor is missing in both models.
 

Offline Fungus

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Re: Handheld meter robustness testing
« Reply #4373 on: January 23, 2022, 08:44:59 am »
I'm not a fan of carrying multiple multimeters

Why would you carry both? You know where you're headed when you're away from the workbench, grab just the one you need.

PS: How will you measure low resistances or power consumption with only a single meter? Some measurements require two. There's also the matter of sanity checking: If you get a weird reading on your single meter then how will you double-check it.
 

Offline rsjsouza

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Re: Handheld meter robustness testing
« Reply #4374 on: January 23, 2022, 12:01:41 pm »
I wouldn't care much about 161e warranty for $50-60 price.
Got anything close to 161e feature wise, better protection around $100?
There is no free lunch. The Fluke 101 is the strict low end of Fluke with robustness but zero features (and quality control issues in my experience). Brymen/Greenlee is what you are going to find with reasonable robustness and more features at the same price range (also Klein). The newer Uni-T models seem to have reasonable mechanical robustness, but electrically they are not as good.

If not, would 161e be safe while working on 240v 3 phase machines? I would mod it to make it more robust but not electrical engineer, and I know it's not allowed to ask for help with that here sadly.
This is a question that can be approached from many angles.

From a multimeter perspective, the UT161E, the UT61E+ and many others (even the throwaways M830B-clones) will probably be just fine working on such systems during normal operation - they can withstand 240V just fine. However, if an unexpected event happens (high energy transients, for example) the chances of the cheaper equipment to survive are much smaller than a more robust one.

From the perspective of the operator and since you asked about "safety", Joe's tests cannot help you. Sure, a meter that survives a low energy transient has a higher probability of containing the damage of a high energy transient, but without testing it is a very far fetched claim. To verify this, a very high energy transient would have to be applied (something that the independent agencies claim to test to the full extent) and the meter would have to either (1) survive without damage or (2) die but in a controlled way to not harm the operator. In this particular scenario, I can tell for sure the M830B throwaways will be much less safe than anything else on the marketplace and will probably blow in your hands - an Uni-T meter would be less robust than a Fluke/Brymen/Klein, but without testing no one can really know.

The suggestion for more than one multimeter is very sound, but only if you are interested in investing twice your lowball budget. In this case, you can have the best of both worlds: the extra features of the Uni-T for the bench and the safety of a simpler robust model for the field.
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 


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