1. The ESD protection circuits protect most of pins. However pins, V+, V-, AGND, DGND and VR1
are not protected enough because the parasitic effect must be decrease. Therefore enough external
protection is needed for assembling, carrying and keeping. In addition, components connecting to
these unprotected pins have to be soldered on board before the IC is soldered.
2. All the zener diodes above are used for IC protection. These protections are needed and these zener
diodes must be soldered on PCB first before soldering ES51926 on.
3. The OVX pin resistance have to be kept below 120kΩ for the capacitance mode accuracy (3/30nF
range). For higher voltage protection, additional configuration of PTC protection is necessary.

=> So this clearly shows how easily this uni-t chip can be damaged and how difficult and hard it is to even solder-on this chip safely onto the tweezer tester board, and how poorly protected uni-t manufactures these testers!

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Additional update: Just to make sure what voltage exactly was given by my Metex M-3800 multimeter in diode beep test that assumably kills processor/controller chips, I measured its output voltage on its probe leads. I used my new portable ZOYI ZT-XT1 universal transistor tester and DMM in one device for that. It showed a constant dc voltage of 2.4449 Volts.
My safety tip in these cases could be to use the 200 Ohm scale measurement instead. That only gives a max measured dc voltage output on the DMM probe leads of 1.0337V!
It of course won't give an detectable audio beep but still shows if there is a straight track connection in the circuit measured. But it will take more time to also read the display value of the Ohm resistance. Especially when it involves measuring all 100 copper tracks!

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Philip, your suggestion to disconnect all the processors Vcc and grounding pins to keep the processor from harms way and using solderjumpers afterwards may still end up in killing your partly disconnected processor. Because without any ground connection to the processor all the voltages on the inputs are still connected and not safe! And in the Uni-T UT116A circuit there are different ground levels too. There is Agnd and Dgnd. And the Battery voltage is given as V- to AGND. But the chip also has several V- also V+ pins too! So there is no telling what just a small ESD discharge might do when you use that method.
Anyway, my bad experience with the unserviceable UT116A means that I probably never will buy any new Uni-T model again.

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Thanks for sharing that informative and similar uni-t processor experience Imoudu! As already was suggested in my article and my post to Philip, these processors probably are very weak and assumably can get (even if partly) detroyed by just using a dmm diode test voltage on their inputs. Which just proves how useless they easily and instantly become for not having any strong prevention structure for incoming very low external currents/voltages! Something that normally never is warned for or is spoken about. Why even the touching of the probes already can cause a small injecting voltage. As you know when two different metals generate a voltage, the setup is typically called a galvanic cell or voltaic cell. But same thing can happen through (ESD) Electric Static Discharge. The weaker these large integrated processor/controllers chips are manufactured without any integrated safety TVS (Transient Voltage Suppressor) diodes the more they can save on manufacturing them, and the more units manufacturers like Uni-T probably will cheaply sell!
And let us hope that no EMP pulse will be generated in the near future, as it likely will destroy all our modern weak completely unprotected devices without ever touching them!

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So I did not make this up. And I naturally didn't kill the tweezer tester by not first disconnecting the 2 AAA batteries because I only measured the circuit connection to Q3 without them attached. And the only voltage I may have injected into the tester only came - as I wrote - from my as Diode beep tester connected digital multimeter. And of course as mentioned I also did test Q3 off circuit in the Peak Atlas DCA75 pro semiconductor tester afterwards. By using the special smd transistor test adaptor for connecting all 3 wire connections to the 1AM npn transistor. In their for that special PCA23 SOT23 Test adapter. Which gave a wrong result stating it was a good Darlington it was NOT!

Removing the multi ground and Vcc pins as you are mentioning to the here used multi 100 pin processor is impossible without breaking any of the tiny pins! And as you and I already claim it must have been my low diode beep test voltage that killed this 3V max processor.
But in my defense my Uni-T UT116A now was already defect twice anyway without my doing! And not only the slide switch already was broken, but now also Q3 and the gone BAT- copper pad. Which was certainly NOT my doing! Why these UT116A testers in my experience definitely are poorly manufactured with a poor support from the Uni-T firm! MY WARNING AS I STATED IS NOT TO USE THE DIODE BEEP TEST ON CIRCUITS IF IT CAN BE AVOIDED!.
But in this case I had no other option because I had to track the connections to the SEL push button pads in the circuit. Also because the manufacturer doesn't provide any service afterwards and neither shares any info about the circuit of this UT116A which is sadly kept a complete secret.

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On what Philip said concerning the use of testing probe on transistors or any other components can affect processor ic baffles me.i need more education on this matter

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