What does the display show when set to that range with the leads not connected to anything?I turned the dial to the V with the squiggle and set to 600 stuck the pins across the wires and it just shows a 1 in the left corner of the screen.
so turning it on to 600 it counts down from over a 1000 to around 20 then settled around 10.connecting the prongs together or on my finger doesn't do anything significant. just bounces around 4
EDIT: VDC seems to look ok, crossing the wire shows an immediate 0