This, in particular:

It still works, but obviously not the right way. Did the Test 02 and everything is fine, it's the range of movement that has changed. It goes from that position shown on the picture to 3/4 of the meter.

I think it is a simple fix, matter of turning the back of the meter a bit, but before I start experimenting, I want to know if anyone had this problem before and is it safe to fix?