EEVblog 1378 - NEW Uni-T UT61E+ Multimeter

[Eheran]

I just got a UT61E+ here in Australia (hi to all my Aussie content producers!), this one here, it came with the following issues:
1. After turning the dial (and also randomly) it sometimes only displayed a "low battery" icon in the top left corner and had to be turned off and on again.
Here is a video of what the issue looks like.
2. God that annoying, super loud beeping all the time! I am used to a nice and quiet 87 V. Put a bit of tape over the piezo, its ok-ish now.

Anyway, I looked inside and found that 2 pins of one chip (I assume it is the µC, the numbers are ground off, so unknown pinout) had a solder bridge, see picture 1. I fixed that, see picture 2, and the issue did not appear again so far (not a lot of testing, just found the bridge and made the post about it here).

What about the CAT II rating with the 250 V fuse? Would it help to just replace the fuse with a higher rated one (like what?) or were there other issues with the PCB, missing/wrong components or what not? It has all its MOFs etc. as far as I can tell, see picture 3. I do want to be able measure 400 V AC/DC somewhat safely, so any recommendations are welcome. And no, I cant use the 87 V, it is still in Germany  :'(

[sanour_islam]

I have a uni-t ut61E+. I used it a lot. I have a question.
The uni-t ut61E+ need 4.5-6V. I want to use a 3.7V battery to run the multimeter with a booster module and make it 6V. Every Booster module have higher frequency and ripple. Is there any problem?