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Fixing A Defect But Brand New UNI-T Tweezer Tester

By on May 27, 2023
Fixing A Defect But Brand New UNI-T Tweezer Tester

On 12 March 2023 a brand new Uni-T UT116A SMD tweezer tester was ordered from the Uni-T meter store and received about 8 days later in that month. Although everything worked it had a bad sliding function selection switch from the start that needed a lot of sliding force to move it into position. And I was hoping that it would get better in time because it was after all brand new.

unit-t tweezer repair

Sadly after just a couple of times being used for a very short period of time the inside slider switch recently no longer worked. And after opening the tester I noticed that its white plastic slider that had the black selection knob on top was completely broken off inside.

Which meant that my brand new tester couldn’t be used anymore even after hardly being used. Why I naturally contacted the seller on Aliexpress after this. And he replied with the question if I maybe accidentally had dropped my tester that could have caused this failure. Of course I hadn’t and I replied that the tweezer tester already was bad right after I received it!

The last message the seller replied was asking me how he could help me. But of course my 15 day buyer protection was now already gone and the seller also already had said that the device easily would be fixable locally. So it was time to start my repair and find a matching replacement slider switch. Which only could be found by searching on Aliexpress by using a snapshot photo of my switch.

how to fix unit-t tweezer

Although I only need one, a set of twenty of these 3-position sliders was ordered through seller Shop296007.

how to repair tweezer

Above photo shows the component board side with the Cyrustek ES51926A processor. The Black slider switch knob and blue Hold and yellow Select push buttons and the LCD are on the other side of this board. And only 4 screws need to be removed to be able to flip this board to the other side out of the case. The 4 here still visible screws hold the plastic transparent LCD cover attached to the board. As next photos show.

fixing smart tweezer

Until my tester slider knob broke off I was rather happy with my affordable tester that also was able to test zener diodes and leds up to about 23V DC because this tester houses a special circuit that generates this higher voltage out of the low 3V from both inserted AAA batteries.

On next photo the now broken brand new 8 pins small 3 position slider switch is shown.

repair smart tweezer unit -t

repairing a tweezer meter

tweezer repair

Above last photo showed another feature which makes this tweezer tester special compared to other tweezer testers. That is its ability to be used as a regular DMM tester with the extra included DMM black and red measuring cables. That both easily can be hooked onto the copper tweezer tester probes. And another feature of the UNI-T tweezer tester is that both + and – marked copper probes can easily be rotated if it is helpful in certain measurements.

Below figure shows the size of the now ordered 3-position slider switch that qualifies as replacement.

part replacement for tweezer meter

The UT116A is an automatic function tester with Auto-range and Automatic-Identification up to 3000 display counts, 30 MOhm, capacity test upto 30mF, resistors as low as <30 Ohm (Ideal as short circuit Beep tester), DCV up to 36V max. Compared to the manual range and identification UNI-T function tester UT116C with 6000 counts, 60 MOhm, 100mF, <50 Ohm. (Max DC voltage not specified).

All in all this tweezer tester is a well designed and affordable service friendly tester but the here used slider switch is apparently very weak and may soon be in need of service if you own this UNI-T UT116A (or UT116C) too!

The Uni-T meter store only supplied a Chinese instruction manual with my UT116A, but here the English manual can be found:

Luckily my other True-RMS UNI-T UT890C 6000 count display DMM doesn’t use any such weak slider switch and is a more sturdy multimeter. And also able to test temperatures from -40 degrees Celsius up to 1000 degrees Celsius. (at 1% resolution). Next to some other features it supports. And I specially bought this DMM thinking it would be handy in case I need to check the temperature of the heater nozzle element of my Ender 5 Pro 3D printer, or any other device with heater element that matters.

And good to know is that both UNI-T meters work on 1.5V x 2 AAA batteries which makes them unique compared to the old on 9V block battery operated DMM’s!

It is however quite disappointing to see what level of service the UNI T meter store afterwards provided after my complaint knowing they were the ones who shipped a problematic working device. Especially knowing that European buyers normally have 2 years warranty on products.

Which in China normally would be about one year. Which would still leave about 10 remaining months of warranty that I never got!

The extra costs involved to order the replacement sliders made this product more expensive and were not refunded by Aliexpress or the seller. Which is bad business!

Until another also hopefully still fixable repair.

albert from netherlands

Albert van Bemmelen, Weert, The Netherlands.

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Note: You can read his previous article on Optonica 20 Watt LED Bar 4000K Repair



  1. Parasuraman S

    May 27, 2023 at 7:44 am

    Many thanks for a very detailed article on a much sought after tool, giving your feedback and also exposing the true color of AliExpress! Good that you were able to fix it at-last!

    • Albert van Bemmelen

      May 27, 2023 at 6:47 pm

      Yesterday I heard in the news that the European Commission in Brussels is making a new law that will start in 2024 to obligate online stores also opening offices in the countries they sell to. Making it possible for customers to deal with the same warranty rules for foreign (Eastern) products as already apply in Europe. Like our present 2 year buyer protection warranty!

      The new legislation on Online Dispute Resolution will allow consumers shopping domestically and in other EU countries to resolve their disputes with traders more easily. Hoping that this will force manufacturers to make better products too!

  2. Mark

    May 27, 2023 at 2:00 pm

    Good repair Albert.
    It is a shame that these sellers know how to work the system.
    At least it gave you another chance for a repair and an article!

    • Albert van Bemmelen

      May 27, 2023 at 6:32 pm

      Yes true Mark. Although another dislike was given after this and my previous repair. Which likely was again from the manufacturer/designer himself who is unhappy with the bad publicity he gets. Or in this case maybe from Aliexpress or the seller, I probably will never know?
      But like they say it is better to get bad publicity than not getting any publicity at all. All that matters is that my review was true and correct and is helping other buyers to fix such a problem!

  3. Waleed Rishmawi

    May 27, 2023 at 4:03 pm

    Ali express is not the best place to buy stuff but sometimes they are the only ones that can provide me with the certain on demand parts. I was surprised that the slide button broke that easily. the UNI tools basically are good brand and recently I bought the UNI thermal camaera from Ebay in the States and so far it is a good tool that cut down on repair time and cost. thanks for sharing and a have a blessed day.

    • Albert van Bemmelen

      May 27, 2023 at 10:35 pm

      Indeed true, for me Aliexpress is also many times the only supplier for the things that I can't buy locally Waleed. And eBay is second for the things that Aliexpress can't deliver.
      Sadly I too was surprised that the normally very good designed UNI-T products in this case didn't hold up to their high quality standard.
      My shop owner friend also bought about 2 years ago a very expensive infrared heat camera. But he regrets having it bought too soon since prices have dropped considerably in the meantime.

      • Waleed Rishmawi

        May 29, 2023 at 2:04 am

        I recently bought a thermal camera from the same company about 300 USA dollars and it is worth having.

        • Albert van Bemmelen

          May 29, 2023 at 1:57 pm

          Understood, my shopowner friend paid with about 700 euro/dollar much more for his heat detection camera at that time. He apparently used it several times successfully to locate and fix Apple computer mainboard issues but probably not enough to compensate for the high purchase price of that camera.

  4. Yogesh Panchal

    May 27, 2023 at 11:19 pm

    Good fix! Albert

    • Albert van Bemmelen

      May 28, 2023 at 2:09 pm

      I'm glad that it was still easily fixable Yogesh!
      Worst thing that can happen to a repair engineer is that a brandnew bought tool already is partly or completely defect at arrival.

  5. Imoudu.O

    May 28, 2023 at 5:07 am

    Hi Mr Albert,Good that you were able to repair the stuff.I also had experienced such treatment from uni-t tools manufacturer on a brand new ut39a+ which was defective when I purchased it. I had to repair it myself.have a nice day

    • Albert van Bemmelen

      May 28, 2023 at 1:57 pm

      I guess seeing what tough looking meter you had bought that it was an internal issue that needed fixing Imoudu? Sorry to hear that but glad that you still were able to fix it.
      Let's hope that my other tough looking True-RMS UNI-T UT890C 6000 count DMM does not also give any such problem in the near future too!
      Apparently there are more sellers that use the Uni-T name in their online shopname.

  6. Maurizio

    May 30, 2023 at 4:17 am

    Very interesting post of yours, thanks. And sorry to read that Uni-T has lowered the quality of its components. However it is not clear to me which switch you have eventually purchased. In fact, from the Figure of the web page on AE it seems you have chosen that with 3 mm handle height, but in the Figure with sizes, a 1.5 mm handle has been necessary. I would like you could clarify this detail. Thanks

    • Albert van Bemmelen

      May 30, 2023 at 7:32 pm

      I bought the 3mm height knob slidehandle not knowing how high the original white broken off plastic handle was (it was gone and sadly couldn't be found). Shorting a bit too high plastic holder however is easy. Making the plastic knob holder higher if its height is too short is close to impossible.

      • Albert van Bemmelen

        May 31, 2023 at 1:07 am

        I probably should have written 'making it shorter' instead of saying 'shorting it' if that meant something else? It is as they say: most things get lost in translation. (also a movie 2003 with Scarlett Johansson and Bill Murray... lol)

        • Albert van Bemmelen

          June 21, 2023 at 6:24 pm

          After the 20 new 3 position slider switches finally arrived on 21 June 2023, and one was used to replaced my broken slider switch, my Uni-T 116A tweezer tester was like a brandnew meter again!
          And it turned out that the 3mm long shaft sliders indeed were the right replacement switches! So luckily there was no need to shorten the shaft by cutting it to make it fit at all!


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