Author Topic: UNI-T UT61E Multimeter teardown photos.  (Read 470014 times)

0 Members and 3 Guests are viewing this topic.

Offline Stinger

  • Contributor
  • Posts: 12
  • Country: fr
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1025 on: April 19, 2018, 08:51:11 am »
We believe a F version with factory backlight and ESR mesurement.  ;D
 

Offline joeqsmith

  • Super Contributor
  • ***
  • Posts: 4829
  • Country: us
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1026 on: April 19, 2018, 12:57:56 pm »
Didn't come with any Cal info. 
Without actual calibration info against a known reference meter, that AD584 box is fairly useless.  It should have come with actual reference values printed on a sticker attached to the bottom of that AD584 rig.  Mine looks like this:



Of course there is some controversy as to whether these sticker values are actual measured values or just some random numbers that someone made up or copied from another sticker.   |O

Even with the sticker, and even if they did correctly copy it from some random HP34401A, you have no idea if the meter they checked it against was even in current cal.   You could have the standard sent in and get a NIST traceable report for it but it may cost far more than the little device cost.   
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline DiddlyJackSquat

  • Contributor
  • Posts: 11
  • Country: sg
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1027 on: April 20, 2018, 02:09:30 am »
One of my mates blew up his UT61E that i sold him  :palm:

idk how he blew it exactly as details are scarce but he told me he blew it in current mode measuring a lipo in current, with the 10A ports and I told big fat bad idea... Now all readings are off.

I'm getting it later from him so i might be able assess the damage

 

Offline escape

  • Contributor
  • Posts: 18
  • Country: us
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1028 on: April 26, 2018, 10:56:29 pm »
Speaking of blow ups, I had a major brain fart yesterday... I had my UT61E in "A" position, test leads connected to COM and 10A sockets.  One test lead was connected to negative terminal of a fully charged 12V car battery, and then I attempted to touch the positive battery terminal with the other test lead.  I only touched the positive terminal for a split second since I saw a spark at the positive terminal and heard the DMM beep.

The DMM still measures voltage, but not current on the 10A socket.  Hopefully I only blew the fuse and nothing else.  Is BS1362 the correct replacement fuse?  I have the Chinese version, not the German version.

Thanks!
 

Offline DiddlyJackSquat

  • Contributor
  • Posts: 11
  • Country: sg
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1029 on: April 27, 2018, 02:44:26 am »
Speaking of blow ups, I had a major brain fart yesterday... I had my UT61E in "A" position, test leads connected to COM and 10A sockets.  One test lead was connected to negative terminal of a fully charged 12V car battery, and then I attempted to touch the positive battery terminal with the other test lead.  I only touched the positive terminal for a split second since I saw a spark at the positive terminal and heard the DMM beep.

The DMM still measures voltage, but not current on the 10A socket.  Hopefully I only blew the fuse and nothing else.  Is BS1362 the correct replacement fuse?  I have the Chinese version, not the German version.

Thanks!

Yes, BS1362 is the correct replacement fuse.
 

Online wasyoungonce

  • Frequent Contributor
  • **
  • Posts: 288
  • Country: au
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1030 on: June 01, 2018, 10:25:07 pm »
To member "Sonny"....you PM'd me but I cannt reply as your post box is full....

So I'll post here and hope you notice as it was wrt to this thread.....

Sorry for the late response...I've been in hospital for last 6 weeks...yet another spinal fusion (I've had quite a few lumber and cervical).   This one worked very well but I've been spending some times on drugs and on the net...a dangerous combination..... :wtf:

Anyway as for the PCB ver...I think I posted pics but am looking for them...or I'll tear it apart when I can.

Pot I used was 2K , 785-9828 RS mrn.  785-9828

Its a 3296Z Bourns pot, 2K 10% +/-100PPM/C, so yeah could have done better here!   I think it was what I could get at the time!.  Another Problem is its centre legs is offset so I had a bit of bending to do prior to fitting... :palm:

I'll do pics soon ummm it didn't have pads to vref IC!

Oh yeah its kept cal ever since changing the pot!

Brendan

edit:
Jeez Sonny your postbox is still full....I cannot PM back to you till ya empty !
And correct pot should have been Bourns 3296x pot as these pins are inline pins and its side adjust or 3296W for a top adj pot.  I'm sure top adj will fit ok. The RS 3296X pot is RS number: 521-9912, mfgr mrn: 3296X-1-202LF, RS cost $4.30 ea.

 
« Last Edit: June 03, 2018, 11:19:39 pm by wasyoungonce »
I'd forget my Head if it wasn't screwed on!
 

Offline sonny

  • Contributor
  • Posts: 13
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1031 on: June 19, 2018, 05:38:40 am »
Jeez Sonny your postbox is still full....I cannot PM back to you till ya empty !
Hello,
Thanks for your post. My postbox is 340% full, I suppose Dave did another shrink to the accounts some time ago. I removed 15 messages and my inbox is still full. Do you know where are the requirements for the accounts, because I can't find them.

I hope you are doing well now after your spinal fusion?

I also noticed that it's not Bourns 3296Z, because of the pins alignment. Bourns 3296X seems to be the best choice. I measured the pot in my UT61E and it shows around 500 ohms. I think 3296X with 1k will be the perfect fit and it will provide better resolution for the calibration.
Regards,
 

Online wasyoungonce

  • Frequent Contributor
  • **
  • Posts: 288
  • Country: au
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1032 on: June 19, 2018, 09:03:59 pm »
There are different versions with different pots ( dividor reference networks)so ensure you replace the OEM with the same specified value.
I'd forget my Head if it wasn't screwed on!
 

Offline sonny

  • Contributor
  • Posts: 13
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1033 on: June 19, 2018, 09:19:29 pm »
There are different versions with different pots ( dividor reference networks)so ensure you replace the OEM with the same specified value.
Hello,
Thanks for your message. As far as I know VR1 is the same 3296X pot with 2k value for all UT61E in production (just different brands). Interesting enough in the manual says 1k for VR1.
 

Offline joeqsmith

  • Super Contributor
  • ***
  • Posts: 4829
  • Country: us
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1034 on: June 20, 2018, 08:56:32 pm »
In Nov 2016, I had measured the temperature drift of my new UT61E and made a video were I compensated it.  I had also changed out the one trimmer pot.  Someone had asked about long term drift and I mentioned I would start collecting some data from mine.  It sounds like some people are seeing a lot of drift.  I can't help but wonder if this is operator or the meter.   

Anyway, here is some data from my UT61E after the temperature compensation taken on 11-21-16:
1mV: 1.02
1V: 1.0001
10V: 10.002
1nF: 1.003

I have had the meter apart a few times since then to make other modifications to it including the larger shunt for measuring 20A and attempting to improve the burden voltage in the uA range.  However, I have been careful not to adjust the trimmers that would effect this little study. 

You can see the in the mV range the meter appears to have a change of 30uV.  However, it's way to small of a change to hang my hat on and way too little time has passed.   I would expect the meter would be fairly stable.  Maybe people are using an unstable source to look at drift?

It's been another 6 months since I last measured the drift of my UT61E.   


How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
The following users thanked this post: BillyD, WhichEnt2

Offline ziplock9000

  • Regular Contributor
  • *
  • Posts: 161
  • Country: gb
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1035 on: June 21, 2018, 01:21:23 pm »
Speaking of blow ups, I had a major brain fart yesterday... I had my UT61E in "A" position, test leads connected to COM and 10A sockets.  One test lead was connected to negative terminal of a fully charged 12V car battery, and then I attempted to touch the positive battery terminal with the other test lead.  I only touched the positive terminal for a split second since I saw a spark at the positive terminal and heard the DMM beep.

The DMM still measures voltage, but not current on the 10A socket.  Hopefully I only blew the fuse and nothing else.  Is BS1362 the correct replacement fuse?  I have the Chinese version, not the German version.

Thanks!
You say German version.. Isn't it a European version because the reason it's different is due to European safety laws?
 

Offline ProBang2

  • Frequent Contributor
  • **
  • Posts: 291
  • Country: de
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1036 on: June 22, 2018, 03:28:28 pm »
You say German version.. Isn't it a European version because the reason it's different is due to European safety laws?

Perhaps that is the case because:
  • It first popped up in Germany.
  • It seems to be like unobtanium, except from german suppliers.
  • It is labeled with the "GS" sign and independent tested from the german TÜV.

Actually it should be even the "European Version". In Germany this version was necessary because of product liability.
Regarding the european laws - let me make some examples, please:
  • A 9 year old boy from New York send a populated PCB to his grandpa in Berlin. The box includes the written message "Look! My first soldered PCB."
    - No Problem with the import to europe. It is clearly not commercial or available in higher counts.
     
  • A clever guy sells a self developed and manufactured special measurement device from Australia to europe. But sometimes the import was denied...
    - That is maybe because he does not marked his device with the "CE" sign. Every commercial product must be (at least) marked with this. With this sign the manufacturer assures that his product is made under consideration of the EU regulations. (Yes! That includes correct CAT ratings on DMM´s too! But remember: The manufacturer labels the products... Hence the "CE" sign is practically useless.)
     
  • Hans Schmidt from Munich ordered a CAT IV rated DMM direct from China. He used it in a CAT IV enviroment. The DMM broke down, he is now very crispy.
    - Because he is himself the importer of the DMM, there is no product liability involved. And there is no way to sue a manufacturer in China...
     
  • His brother, Peter, ordered the same DMM for himself. After his brother was well done and crunchy he selled his own device. Now is the buyer heavy injured by electrocution under similar circumstances as Hans.
    - Depending of the local laws is the importer (Peter!) legally responsible. Even as a private person.
     
  • Same case as 3, except: Hans bought the DMM from a german supplier (like Distrelec, Pollin etc.).
    - The supplier as the importer is full liable that the product he sells is fullfilling the claimed characteristics. Therefor he is fully legally responsible.
     

I hope, I could made it clear. I know: Too much waffling...   :blah: :blah: :blah:
 
The following users thanked this post: ziplock9000

Offline ziplock9000

  • Regular Contributor
  • *
  • Posts: 161
  • Country: gb
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1037 on: June 22, 2018, 06:37:06 pm »
That makes sense, thanks  ;D
 

Offline sonny

  • Contributor
  • Posts: 13
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1038 on: July 04, 2018, 06:14:07 am »
It's been another 6 months since I last measured the drift of my UT61E.   
You had temperature compensation inside the unit, right?
 

Offline rollatorwieltje

  • Supporter
  • ****
  • Posts: 567
  • Country: nl
  • I brick your boards.
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1039 on: July 26, 2018, 11:15:31 pm »
Just thought I'd share this, don't leave your UT61E in the sun, the screen will turn black. After cooling it down it recovered. My Fluke 101 and a cheapo Ohmeron mt488e didn't have this "problem".
 

Offline ziplock9000

  • Regular Contributor
  • *
  • Posts: 161
  • Country: gb
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1040 on: July 27, 2018, 12:37:28 am »
That's not specific to the UT61E, it happens to almost all LCD displays
 

Offline joeqsmith

  • Super Contributor
  • ***
  • Posts: 4829
  • Country: us
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1041 on: July 27, 2018, 08:57:21 am »
It's been another 6 months since I last measured the drift of my UT61E.   
You had temperature compensation inside the unit, right?
Sorry, I missed your question.   The meter has had several modifications done to it at this point.  Yes, I did modify the reference to attempt to make it more stable with temperature.  Originally it was one of the least stable meters I looked it.   It's actually more stable now than many of the meters I have.  I also changed out the 10T trimmer pot while I was at it, assuming this was the major contributor.  It did not turn out to be the problem and I just left the new part in there. 
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
The following users thanked this post: jackobo

Offline jackobo

  • Newbie
  • Posts: 1
  • Country: ie
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1042 on: August 01, 2018, 08:11:16 pm »
joeqsmith: could you please  specify, what exactly nominal of the resistor you put in between C41-42 in your Part 1 of the robustness video to prevent EMC shock to the main chip?thanks
 

Offline uncle_sem

  • Newbie
  • Posts: 2
Re: UNI-T UT61E Multimeter teardown photos.
« Reply #1043 on: August 24, 2018, 11:26:59 pm »
spare LCDs for ut61e here: https://aliexpress.com/item/UNI-T-UT61E-dedicated-LCD-screen-LCD-size-65mm-43-mm/32906907573.html
got one (well, i'm ordered 3pcs) and very happy about it. I guess it's even little better than original one
 
The following users thanked this post: Mickle T., jackobo


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf