Fatshark transmission goes dark

[skydrum]

Help! I attach battery, GoPro and goggles - power everything up to make sure goggles are transmitting before flight, and they are - I then plug in Phantom battery and the goggles go immediately gray, not completely black, just gray and no transmission. I've even used a separate battery for the goggles and then plug in 2nd battery for Phantom and the goggles go immediately grey then too. Seems like the Phantom battery is overriding something. Anyone had this kind of problem? It has happened more than once to me but sometimes won't happen for a number of flights before rearing it's ugly gray head again. I'm stumped! Any ideas??