New TRMS Uni-T UT139C DMM is available now

[Wytnucls]

I was more interested in their new oscilloscopes.

[Legit-Design]

MCU inside my UNI-T UT139C, pic below. Found this picture on chinese site: http://translate.google.com/translate?hl=en&sl=zh-CN&tl=en&u=http%3A%2F%2Fzhidao.baidu.com%2Fquestion%2F563770993.html Mine had same MCU inside. At least is suspect it is mcu.
I can provide teardown photos if enough people are interested.
Yes, it has few movs and few ptc, 600V fuses. 10A fuse is physically smaller than "600mA" fuse, no room for bigger fuses and holders like UT61C/E series has.
NCV, non contact voltage is really sensitive, it has 4 ranges, one to four dashes and it beeps more with more dashes.

I just had excuse to take it apart, K-type temperature function was acting up. When it was in room temp it was 28 C when it should be 25 and when I heated it with my hand it went DOWN, I heated the tip with my lighter and temp went down to -200C. Now I took the batteries out and it's working normally again, room is 25 and hand is around 30, boiling water is around 98 to 99 C what is just tested, heat from lighter is really hot is just burned the heatshrink from k-type a bit. Earlier today I discovered if I short the temp input with a probe it showed me current room temp, but that wasn't the case. I put my meter in the freezer and it couldn't read the K-type properly anymore. It was around -20 below what it should be.

[Lightages]

I would like to see more images.

[Legit-Design]

http://imgur.com/a/984K7 Gallery with all the pictures.

Please excuse these amateurish shots, took these with my smartphone with flash on, most of them are in focus.
Backlight is quite weak compared to UNI-T UT-61D, but good enough to see in dark.
Meter feels rugged when handled, I wouldn't be afraid to drop it.

MOVs are http://www.thinking.com.tw/documents/en-TVR.pdf
TVR07681

[Monkeh]

Well now, that looks a lot like a BS1362.

E: That's because it is, with a 600V/200A rating as well as 250V/10kA.

[Legit-Design]

Oh and the most important things autoranging is slow, in resistance, like with UT-61D but Continuity beeper is super fast.
Binding posts are solid type and feel really good, much better than with my UT-61D/E. I have all three meters so I can do comparison.
Manual quotes screen updates 2-3 times per second, looks faster than UT-61D, but doesn't have that analog bar graph thing.
Max min includes Max-Min, so it shows difference.

EDIT: Few bits... that oscillator is soldered from its can to the board. Case is held by two self tappers, battery cover with the fuse inside is held by machine screw into metal insert.

More: microamps range resistance 101 ohms, milliamps 2,1 ohms, amps less than 0,10 ohms, amps range is really tricky to measure.  All measured with UT61E with probes relatived out.
 for UT61D those are microamps 50 ohms, milliamps ~0.8 ohms (I think dave also has covered ut61d in his 100$ MM shootout)

One more thing to point out, probes are super dull compared to normal uni-t 61d/e probes

Please check the gallery for more pictures: http://imgur.com/a/984K7/all

What else should I test with this meter? I don't have any accurate references, but I can do comparative measurements since I doubt all three of my Uni-t meter are out of cal.

[retiredcaps]

What else should I test with this meter?

Does it overshoot?  That is, if you connect the UT139C to a DC or ATX power supply, does it show the correct DCV reading immediately? 

For example, if the power supply is set to 12.0V DC and turned off and then on, does the multimeter show 18.1V (this is overshoot), then 12.3V, and then finally 12.0V?  Or does the UT139C show 12.0V right off the bat?

[Legit-Design]

Does it overshoot?  That is, if you connect the UT139C to a DC or ATX power supply, does it show the correct DCV reading immediately? 

For example, if the power supply is set to 12.0V DC and turned off and then on, does the multimeter show 18.1V (this is overshoot), then 12.3V, and then finally 12.0V?  Or does the UT139C show 12.0V right off the bat?

Couldn't get any of my three meters (UT61E UT61D and UT139C) to overshoot with 12 volts.
However I could replicate https://youtu.be/3-_dUB8vy8U?t=25m27s Daves test from his shootout and get consistent overshoot with UT61D switching 3.3V rail. Sometimes 4.5V sometimes 4.7V, or even 5V, and I could get atleast 4.5V oveshoot consistently. UT136C didn't show any overshoot with this setup. Sometimes I could get UT61E to overshoot 18V or so, but that was more random than consistent. UT136C gets there more gradually it shows 2.3 to 2.9V for a split second before goes to 3.3V.

[lpc32]

Any new info or opinions? I can't find a manual, nor any official info in the manufacturer site.

[lpc32]

Well, found the manual in some German site:
Mirror: http://www.mediafire.com/download/cy2ysi5iixia6g4/uni-t_ut139a_ut139b_ut139c.pdf
Original URL: http://www.pinsonne-elektronik.de/media/daten/UT139A_B_C_eng_uni-t_pinsonne.pdf

[Legit-Design]

Frankie has these on his ebay store: http://www.ebay.com/itm/Uni-T-UT139C-True-RMS-Digital-Multimeter-Temperature-NCV-Backlight-/171213085325?pt=LH_DefaultDomain_0&hash=item27dd185a8d
For US $49.99 I recommend buying from him, fastest shipping on ebay I've seen (from Hong Kong).

Also a member on this forum https://www.eevblog.com/forum/profile/?u=26834. He can also source other things which are not listed on ebay.
And he ships fast, faster than any other ebay seller. He will remove those batteries from the package, but thats so that customs wont stop the parcel, I've had parcels sent back to seller because because some other parcel included batteries, so they stopped whole load of packages.

Some special prices for forum members:
https://www.eevblog.com/forum/buysellwanted/brand-new-uni-t-ut61e-for-sale/

Brand new Uni-T UT61E for sale
$55 (US customers) / $57 (non-US customers)

https://www.eevblog.com/forum/buysellwanted/fs-digitek-dt-4000zc-tekpower-tp4000zc-with-discount

Digitek DT-4000ZC / TekPower TP4000ZC with discount

It is listed at $36.99 (worldwide shipping included), but members can contact me here directly and get one for $35.

[retiredcaps]

Video review and teardown by electronupdate, an eevblog member here, just posted Jan 24, 2014.



Franky gets a shoutout.

[electronupdate]

Video review and teardown by electronupdate, an eevblog member here, just posted Jan 24, 2014.



Franky gets a shoutout.

It's an interesting meter.  The calibration mostly appears to be set by inside a serial eeprom (no trim pots on the board).  Good for stability, not so good for service.  I could not find any details on the main controller IC.

The meter has 600V rated fuses which match the CAT rating which is also a step in the right direction (the previous ut61e I tore down used 250V BS1362 appliance fuses).

Another  item of note is that UNI-T needs a product manager.  Each meter they produce does not fit into a nice cadence of features.... one  always needs to make a decision on odd axis such as temp sensor versus resolution.

[Legit-Design]

Please check the gallery for more pictures: http://imgur.com/a/984K7/all

Video review and teardown by electronupdate, an eevblog member here, just posted Jan 24, 2014.

Franky gets a shoutout.

Looks like they updated the board slightly, mine has silkscreen place for that bodged crystal. (

) That new board doesn't have that and SMD crystal is in place.

[lpc32]

Thanks, electronupdate.

Re board changes, maybe there are different versions in different regions?

There are a few more details I wonder about, but I'll find out soon enough.

[lpc32]

Some impressions:

Build quality feels decent.

The backlight turns off after a few seconds by itself. Quite annoying.

The probes' tips aren't sharp. Similar to a ballpoint pen.

[JonathanLee]

DTM0660L IS HYCON HY12P65 Digital Multi-function Meter (DMM) ICs
http://www.hycontek.com/e-page2-HY12P.html

[retiredcaps]

DTM0660L IS HYCON HY12P65 Digital Multi-function Meter (DMM) ICs
http://www.hycontek.com/e-page2-HY12P.html

Thanks for sharing that information.  I would have never figured that out.

[awardcat]

DTM0660L IS HYCON HY12P65 Digital Multi-function Meter (DMM) ICs
http://www.hycontek.com/e-page2-HY12P.html

  but...this page says HY12P65 have 5000 counts , but ut139C have 6000 counts

update : in the datasheet is 6000 counts

[IGNT]

Woow that seems, good stuf ...  how can i buy it, in indonesia.  would you share me a presaller in indonesia who sale this good stuf...

regards

IGNITER

Note : Sorry About my English  language , because i javanese... 

[PedroDaGr8]

Woow that seems, good stuf ...  how can i buy it, in indonesia.  would you share me a presaller in indonesia who sale this good stuf...

regards

IGNITER

Note : Sorry About my English  language , because i javanese... 

Franky (iloveelectronics) on this forum sells this meter.

http://www.ebay.com/itm/171213085325


He ships pretty much worldwide from HK. You might be able to get it a tad cheaper via this forum as he doesn't have to pay ebay fees.

[IGNT]

thank's for nice reply, PedroDaGr8   

, my apologize ,for late response.

Regardz

IGNITER

[boo9]

Anybody has a link to a _searchable_ PDF for UT139C ?

[lpc32]

Not searchable, but the PDF on UniT's site is better quality than the previously available one:
http://www.uni-trend.com.cn/uploads/soft/wanyongbiao/UT139A.UT139B.UT139C%20-Manual-en.pdf

[mariush]

Here, I OCR'ed it ... careful though, it's not proofread, no spell checking, just automated ocr .