If you are only getting snow for your video this could mean a couple things.
- 1 VTX is in Pit Mode
- Goggles are on a different channel then what you have the VTX set to
- The VTX is not powered.
If the VTX was working and you are on the correct channel, then you would get at least a black screen. For this problem check the goggles and make sure you are on the same channel as the VTX. Make sure the VTX is powered, there should be some kind of indication like a LED on your VTX. Maybe try swapping a different VTX.