MY DSO NANO V3 reads 0 value for Vmin instead of a negative value for AC signal

I have owned my DSO NANO V3 for over 6 years, but during these years I have rarely used it. In fact I kept it in a drawer. Recently I brought it out to use, I noticed the battery was dead, changed the battery and updated the firmware to the latest version (DSO Nano Official Firmware V4.32 ).

I tried to measure the Vmin of an AC sinusoidal signal and I got 0.00V instead of a negative value ( -16.8V from my measurements). I know it should be a negative value, as the trough is below the zero line of the oscilloscope.

Is this the normal operation of Vmin or is my NANO faulty? I have attached an image.

Also whats the meaning or function of Sensitiv under Tr

in the NANO menu?



Can you check the measuring probes? it’s a 6-year-old device and the probs might be damaged somewhat!