I just happily received my new Megalodon today, unwrapped it placed a battery in and nothing. I did not panic, I took a look at the unit, which seems finely made, thought OK, try a new battery and new carto... still nothing. The same battery and carto will work on everyone of my other mods but not the Megalodon, does anyone have any suggestions? At one point I was trying my 18650, 18350 and even my 14650 batteries and had no luck. (Scratching head).