With a little delay i got answer to my question about functions and fuses. I asked directly to HQ of Uni-T and here is what they came up with. Let me just remind you that Manual does not have any "usefull" information inside as you also could see in my video i made.
Hi, as for IEC61010CAT?1000V, it is the over-voltage safety standard. In fact you cannot input such high voltage value under current ranges. Because the shunt resistance is very small, PCB will be burned when short-circuiting the input terminal and COM under such high voltage input. That is why HRC kind of fuses are not used inside.
Second, concerning functions PEAK, MAX, MIN, the manual actually offers clients functions and specifications that the meter has, so are PEAK, MAX/MIN ranges, would you please check again? As far as the range -4V---4V, the default after UT71D is powered on is 4V range, you need to select desired ranges manually. When performing Max/Min function, Max/Min values are only displayed and on second display instead of main display screen.
When test probes are disconnected, the digit bouncing is caused by the interference. Since the input impedance is 10M, so the accuracy for the meter can not be affected during measurement. so is PEAK mode
Regarding HOLD function, you should press down HOLD button during measurement to save readings you have got. If the button is pressed first before measurement, you cannot go on with the measurement any more,
With respect to the gap between 400mA and 10A, the shunt resistance is very small and the potential will be close to zero voltage when short-circuiting between any terminal and COM. that is why no spark gap happens between these two terminals. The flat ribbon is needed inside based on circuit design, which offers misconnection alarm in current ranges. So resistance difference does exist, however the soldered resistance is the lowest, we have take this kind of issue into consideration when doing the software calibration.
We are sorry causing you such inconveniences when using our meter. Thank you for your cooperation, please feel free to contact us if you want to know information about the meter. Thank you very much!