UT139E and UT139S Digital Multimeters - no discussion? - Page 1
Forum section: electronics / testgear

author: DavidA
author_rank: Contributor
timestamp: December 13, 2017, 03:34:28 am
content: Many people here seem familiar with theUT139Cdigital multimeter, however Uni-Trend show aUT139EandUT139Smodel on their website. However searching for these models on EEVblog returns no results. Not a mention of either of them.This surprises me, because I'm curious about whether they might be newer than the UT139C, which has been around for a few years now. I'm wondering how the UT139C might stack up against either of these, or indeed other new DMMs like the BSIDE ZT301, which is about 30-60% of the price of a UT139C.Does anyone know what DMM IC these UT139E/S models use?

author: hli
author_rank: Frequent Contributor
timestamp: December 13, 2017, 11:08:54 am
content: For the BSIDE ZT301: I did not find any specifications whatsoever, so you don't know its accuracy. It might be cheap, but I would not trust it.For the UT139E/S: when compared to the 139C, it has the same accuracy. But it comes with Low-Z mode and a LPF for AC measurements. This might be interesting depending on your needs. Apart from that I would assume any review of the 139C with regards to quality would still apply to the 139E/S.

author: rsjsouza
author_rank: Super Contributor
timestamp: December 13, 2017, 12:43:00 pm
content: Quote from: hli on December 13, 2017, 11:08:54 amI saw the same when comparing the two, with the addition that all models claim to be ETL verified, which gives some added confidence. The UT139C, however, has a "VFD" mode that is usually a LPF on AC measurements.Regarding quality, it is plausible they are comparable but ideally they should be independently checked by an unsuspicious third party with a random purchase. The E/S models certainly seem newer and are a category on their own - Uni-T bundles them together while separating from A/B/C variants.

author: Maxlor
author_rank: Frequent Contributor
timestamp: December 13, 2017, 01:49:40 pm
content: Mmh, not that interesting, the new models. NCV and AC-LoZ aren't that useful for electronics, and the added bar graph isn't worth the $10 extra (-E vs -C). The -S goes for $70, seems a bit much? I like those EBTN displays, but I don't think I'd pay so much extra just for that? Not to mention that while it looks nice, it also requires more power. I reckon that battery life on the -S model will be 50-100 hours.

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2017, 02:14:22 pm
content: Quote from: hli on December 13, 2017, 11:08:54 amThe specs are listed in many places, eg.here. It's basically a 0.5% meter, the same as those Uni-Ts. 6000 counts on screen is down in the noise level for meters of this spec (6000 counts is 0.016% accuracy - easily enough for 0.5% readings).I'd trust one of those as least as much as anything made by Uni-T.The new wave of low cost meters from China has been extensively discussed here and no problems found. Of the two I own I prefer the ANENG AN860B+ (but that's just me).Quote from: Maxlor on December 13, 2017, 01:49:40 pmBar graphs can be useful.I certainly wouldn't pay extra for a power-sucking screen, no matter how pretty.

author: Hydrawerk
author_rank: Super Contributor
timestamp: December 13, 2017, 02:43:09 pm
content: LoZ is shit on UT139E or S. See the page 9 of user manual.https://drive.google.com/file/d/0B4Jyby-tjH5oOUNDZTREUjdhbDQ/view

author: hli
author_rank: Frequent Contributor
timestamp: December 13, 2017, 02:51:38 pm
content: Quote from: Fungus on December 13, 2017, 02:14:22 pmThe UT139E is, apart from the DC voltage ranges, more accurate than the ZT301 (e.g in DC amps its 0.7% vs. 1.5%)Quote from: Fungus on December 13, 2017, 02:14:22 pmI think you are confusing accuracy with precision. None of the meters is 0.016% accurate.Quote from: Fungus on December 13, 2017, 02:14:22 pmI would not trust a $25 meter that claims a 600V CAT III rating. AFAIR the verdict on the UT139 series was that they are OKish for mains voltage (in contrast to the chinese version of the UI61 series which was lacking all the needed input protection). For low-voltage electronics it doesn't matter, however.

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2017, 03:41:54 pm
content: Quote from: hli on December 13, 2017, 02:51:38 pmResistance is more accurate on the ZT301 (0.5% vs. 0.8% on the Uni-T), so...Both are accurate enough for ordinary work.I was really just pointing you to a place to find the specs (you said you couldn't find them).Quote from: hli on December 13, 2017, 02:51:38 pmNo, I'm referring to the fact the 6000 counts displayed is enough for 0.5% meters (it's even enough for a 0.05% meter).

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2017, 04:02:39 pm
content: As far assafetyrobustness goes, a UT139C wasn't anything special in Joe's tests:https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/It's a little bit better than most of the new Chinese meters but not much.It's not in what I'd call the "safe" zone, and it's not what's printed on the front (CAT III 600V).

author: Maxlor
author_rank: Frequent Contributor
timestamp: December 13, 2017, 04:08:15 pm
content: Quote from: Fungus on December 13, 2017, 04:02:39 pmThe safety standards don't require the meters to survive HV spikes, they only require them to protect the user. Joe's tests aren't about safety (which the CAT ratings are.)

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2017, 04:20:02 pm
content: Quote from: Maxlor on December 13, 2017, 04:08:15 pmI know joe's tests aren't about safety, that's why I crossed out the word "safety" above. Joe doesn't even test the amps ranges, which is where most of the sparks usually fly.The first PTC in his Uni-T blew apart at 2/3 of the CAT rated voltage and a small amount of energy. I wouldn't like to be holding it in my hand at 6000V with the full CAT energy levels (which are far higher than joe's little box can manage).FWIW the video is here for people to decide:

author: rsjsouza
author_rank: Super Contributor
timestamp: December 13, 2017, 04:34:28 pm
content: Quote from: Fungus on December 13, 2017, 02:14:22 pmI agree as well; bargraphs can be quite useful to detect if the meter is set to DC on a line that also has an AC component - especially because this meter does not have AC+DC mode. However, this is only useful if the update rate is fast. Does that warrant the extra $10? YMMV.Quote from: hli on December 13, 2017, 02:51:38 pmUni-T claims the UT139 line has the ETL seal, which gives confidence it was at least tested at a certain point in time. However, trust is only warranted if the manufacturing process stays the same across the years - Uni-T does not have a stellar reputation in this regard, that is probably Fungus' point above.

author: HKJ
author_rank: Super Contributor
timestamp: December 13, 2017, 06:41:02 pm
content: Quote from: Fungus on December 13, 2017, 03:41:54 pmI would say that is 10 times to good for a 6000 count meter. It has to measure precise from 600 to 6000, not only at 6000, i.e. the worst precision is always just after a up range shift, that is a 600 reading.

author: Fungus
author_rank: Super Contributor
timestamp: December 14, 2017, 11:16:54 am
content: Quote from: HKJ on December 13, 2017, 06:41:02 pmhttps://en.wikipedia.org/wiki/Benford%27s_lawI agree though, all meters should be 999, 9999, 9,9999 counts (or whatever). I don't know why they aren't.

author: Fungus
author_rank: Super Contributor
timestamp: December 14, 2017, 11:50:24 am
content: Quote from: hli on December 13, 2017, 02:51:38 pm...'ish'.All I'm trying to say is that "safety" doesn't belong on a list of reasons to buy a UT139. If you've got it on yours, think about taking it off.For once-in-a-blue moon checks: If youtriplecheck that the meter's in AC mode and all the cables are in the right holes then I'd trust one of those cheapo meters as much as a UT139.nb. The type of fuses, etc., aren't really a factor incorrectuse of the meter, ie. You shouldn't ever be connecting it to AC mains in any of the amps modes.

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 14, 2017, 11:54:05 am
content: Okish isn't ok at all. Anything used for mains should be plenty good and reliable.

author: hli
author_rank: Frequent Contributor
timestamp: December 14, 2017, 01:18:26 pm
content: Quote from: Fungus on December 14, 2017, 11:50:24 amIt isn't (thats what my U1252 is for).Quote from: Fungus on December 14, 2017, 11:50:24 amYes, thats my definition of 'OKish' - be careful, and it will not kill you.Quote from: Fungus on December 14, 2017, 11:50:24 amAccording tohttps://www.eevblog.com/forum/beginners/opinion-on-a-bside-zt302-multimeter/25/the ZT302 has no input protection at all (whereas the the UT139C has at least some MOVs and PTCs, even though it could be better). The clearances could be better, and I have not found images of whats happening under the battery holder. To me this is not even 'OKish' (its about as bad as the original UT61E)So I would not connect the 301/302 to mains, even after triple checking. To me there still is a difference between an $20 and a $40 meter, even if its not that much.

author: Fungus
author_rank: Super Contributor
timestamp: December 14, 2017, 02:54:10 pm
content: Quote from: hli on December 14, 2017, 01:18:26 pmNone apart from the big yellow thing in the middle labelled "PTC1".... and those two black things in front of it, which are clamping transistors. That's protection, too.Also those blue MELF resistors near the fuse:

author: DavidA
author_rank: Contributor
timestamp: December 14, 2017, 08:12:16 pm
content: Does the ZT301 have similar protection components? However I can check for myself soon, as I ordered a ZT301 as I'm curious about it.EDIT: oh, sorry, those are pictures of a ZT301. I thought we were discussing a ZT302 in the earlier post though. Sorry for the confusion!

author: gwojew
author_rank: Newbie
timestamp: April 16, 2018, 02:01:18 pm
content: LoZ function suggest that UT139E/S has different input than in UT139A/B/C.Has anyone got it and is willing to share some photos?I’m curious if Uni Trend improved this model robust-wise?I’ve seen Joe’s Smith tests on UT139C, which was very informative, but results were rather average..

author: gzfelix
author_rank: Newbie
timestamp: May 06, 2018, 11:56:57 pm
content: UT139E.

author: gzfelix
author_rank: Newbie
timestamp: May 06, 2018, 11:59:23 pm
content: And the fuses UT139E uses.600V 600mA600V 10A

author: fkfaraz
author_rank: Regular Contributor
timestamp: May 17, 2018, 10:36:14 am
content: hi gzfelixdid u make any video of that e-model or can u make it..... i am really interested in this metereven just turning it on and showing some basic measurement will help me a lot to decide..........

author: gwojew
author_rank: Newbie
timestamp: May 23, 2018, 09:06:29 pm
content: Here’s my UT139SBoard looks pretty much the same - Rev08.1As far works fine, but I haven't used LoZ function.

author: fkfaraz
author_rank: Regular Contributor
timestamp: May 24, 2018, 09:55:17 am
content: hi gwojewhope u will be doing well.....can you make any video of that meter..... i am really interested in this metereven just turning it on and showing some basic measurement will help me a lot to decide..........how about the battery life? can u do some basic test?your help will be really appreciated.

author: Travie21
author_rank: Newbie
timestamp: January 31, 2019, 03:03:37 am
content: Hello guys. Can I ask what's the problem of my meter? Its UT139E. I accidentaly plugged it on AC while its on resistance mode. I can still read low resistances from 1-1kohm I guess, but not be able to read over Mega Ohm. Continuity still works fine and diode test. The capacitance does not work, its stocked on 0.000 micro fara unlike before it starts on nano farad. Ac and DC voltage still works, but DCmV is on OL but indicating a high voltage on the corner of the meter. NCV does not also work now. I checked the board and see no burned or any signs of visual damage on the components. I also checked the fuses and still works fine. Hope you can help me guys.

author: Fungus
author_rank: Super Contributor
timestamp: January 31, 2019, 07:20:14 am
content: Quote from: Travie21 on January 31, 2019, 03:03:37 amSounds like you zapped it.Quote from: Travie21 on January 31, 2019, 03:03:37 amDamage isn't always visible, fuses are only used on current ranges.

author: HKJ
author_rank: Super Contributor
timestamp: January 31, 2019, 07:24:16 am
content: A guess is that you have zapped the input protection transistor pairs. There can be a couple of these pairs.

author: Fungus
author_rank: Super Contributor
timestamp: January 31, 2019, 08:29:56 am
content: Today's lesson: Don't use non-CAT-rated muiltimeters on AC mains.(in fact, don't useanymultimeters on mains if you can avoid it, try plugging in in a lamp, they tell no lies)This is a real man's mains tester:

author: Hydrawerk
author_rank: Super Contributor
timestamp: January 31, 2019, 01:47:17 pm
content: Quote from: Travie21 on January 31, 2019, 03:03:37 amWas it 230VAC or 2000VAC from a microwave oven transformer??

author: Travie21
author_rank: Newbie
timestamp: February 01, 2019, 11:35:57 am
content: Its a 230 VAC

author: Travie21
author_rank: Newbie
timestamp: February 01, 2019, 11:36:44 am
content: So theres no way in recovering my meter?

author: HKJ
author_rank: Super Contributor
timestamp: February 01, 2019, 11:43:16 am
content: Quote from: Travie21 on February 01, 2019, 11:36:44 amRemove the protection transistors, if it works then, solder new protection transistor in.

author: Travie21
author_rank: Newbie
timestamp: February 01, 2019, 11:49:00 am
content: Btw my meter still works. But the resistance mode is unstable. It blinks from 0000to OL. DCmV displays OL and a HighVoltage symbol pops. NCV and Capacitance does not also works. But anything else still works fine. Any guess?

author: Fungus
author_rank: Super Contributor
timestamp: February 01, 2019, 01:49:00 pm
content: Quote from: Travie21 on February 01, 2019, 11:49:00 amNice definition of "still works".Quote from: Travie21 on February 01, 2019, 11:36:44 amNobody knows for sure, we can't see it from here.Quote from: Travie21 on February 01, 2019, 11:36:44 amHKJs guess is the most likely but at the end of the day, things break. Learn from it and move on.

author: Hydrawerk
author_rank: Super Contributor
timestamp: February 01, 2019, 10:30:28 pm
content: UT139E has some input protection, it should survive 230V, it is not much.http://en.uni-trend.com.cn/index.php?m=content&c=index&a=show&catid=174&id=185In the user manual, they say it has a 600V protection on all ranges.http://en.uni-trend.com.cn/uploadfile/2018/1129/20181129032713354.pdf

author: Travie21
author_rank: Newbie
timestamp: February 02, 2019, 12:14:17 pm
content: So should I check the PTC?

author: Fungus
author_rank: Super Contributor
timestamp: February 02, 2019, 12:59:47 pm
content: Quote from: Travie21 on February 02, 2019, 12:14:17 pmYes!

author: Travie21
author_rank: Newbie
timestamp: February 02, 2019, 01:13:24 pm
content: Should I desolder it first? Or I can test it while its on the circuit? Sorry, I'm just a noob in electronics

author: Travie21
author_rank: Newbie
timestamp: February 02, 2019, 03:09:39 pm
content: May I know what kind of PTC are used on 139E?

author: Travie21
author_rank: Newbie
timestamp: February 02, 2019, 04:20:48 pm
content: https://lygte-info.dk/review/DMMUNI-T%20UT139S%20UK.html

author: daedalux
author_rank: Contributor
timestamp: April 04, 2019, 10:57:36 pm
content: WMZ12A

author: paulbt
author_rank: Regular Contributor
timestamp: June 02, 2020, 02:11:01 pm
content: Hello everyone !I saw people are quite interested about this 139E/S series. I had a thought to buy the S one for a couple of weeks and I finally did it ! I made the purchase from TME last week and today I managed to open it's case and then do some basic tests.First I want to show you some close-ups from the inside:

author: paulbt
author_rank: Regular Contributor
timestamp: June 02, 2020, 02:41:50 pm
content: ...then I did some basic comparison measurements against a calibrated Agilent 34410A 6 1/2 digit bench multimeter.On DCV it reads ~0,1% more than the Agilent. Example: 20,000xx V on Agilent and 20,02 V on UNI-T.On Ohms scale it reads <1% both less and more than the Agilent, the biggest difference was seen on low value resistors (<60 ohms).On uA and mA DC scales it reads identical with the Agilent, limited to the number of digits the UNI-T displayed. I tried random values from about 10uA to 500mA (with shorted PS).On ADC scale it reads ~0,2% less than the Agilent. Here I tried values from tens of mA to about 3A (again with shorted PS).On mV DC scale it reads almost identical with the Agilent, even if the voltage I was measuring was a bit jumpy (due to noise or PS ripple). You can see the head-to-head comparison in the videos below:

author: paulbt
author_rank: Regular Contributor
timestamp: June 03, 2020, 12:54:05 pm
content: Update !Someone here asked about current consumption and battery life for the UT139S. Here are my results:- at 3.2V supply (or 2x 1.6V full alkaline batteries) and high brightness display (default setting), it draws 19mA and with low brightness it draws 10mA.- at 2.4V supply (or 1.2V per battery), the low battery indicator appears and it draws 30mA @ high brightness.- below 2.22V it will beep, shutdown and continue beeping once every few seconds. Right before this happens, it draws 35mA.The test was done using my Aim-TTi PL601 power supply and during this whole time I was measuring a random voltage and the reading was rock steady!More tests will follow up using a function generator (frequency, duty cycle, max/min recording). If you have any wishes/ideas for testing, please post them here.

author: paulbt
author_rank: Regular Contributor
timestamp: October 15, 2020, 12:39:05 pm
content: Hello,I'm back with two interesting little tests. Please read the video descriptions.

author: Fungus
author_rank: Super Contributor
timestamp: October 15, 2020, 12:50:16 pm
content: Quote from: paulbt on October 15, 2020, 12:39:05 pmTry getting some decent leads with sharp points.Quote from: paulbt on October 15, 2020, 12:39:05 pmLimited bandwidth in AC mV mode. Not uncommon, I'm sure it's buried in the specs somwhere.

author: Wytnucls
author_rank: Super Contributor
timestamp: October 15, 2020, 12:58:20 pm
content: Continuity test seems fine to me. Pretty fast and latched.A lot of meters struggle with large DC offsets while measuring AC.

author: paulbt
author_rank: Regular Contributor
timestamp: October 15, 2020, 01:34:47 pm
content: @ FungusFor first video: I tried many quality probes like agilent, fluke and brymen, but it does the same: beeping is not continuous when it should be. If I short the probes together the same thing happens...I'm pretty sure it's the meter...For second video: There is only 100Hz, I don't think it's a matter of BW limit, more like a matter of DC offset. Please look careful what I'm trying to show in the video or read the description.Overall, I'm aware that it is a mid-priced dmm and for sure you can't have the quality/functionality of a high-priced one.I made those video just for info/review reasons.

author: Fungus
author_rank: Super Contributor
timestamp: October 16, 2020, 02:18:48 am
content: Quote from: paulbt on October 15, 2020, 01:34:47 pmSo why did you spend the entire video banging the probes around and poking at a PCB? Just short them.Quote from: paulbt on October 15, 2020, 01:34:47 pmDescription in thread is "Uni-T 139S bug".

author: paulbt
author_rank: Regular Contributor
timestamp: October 16, 2020, 07:08:16 am
content: @ FungusI don't know why I did not short the probes between eachother and I chose to use a pcb instead...If you click the video title it will automaticaly open youtube and there you can see the description I'm telling about.