Contact Fat Shark customer support. I haven't had to work with them directly myself but from what I have heard they will help as much as possible with regard to getting issues resolved up to the point of having goggles sent in for repair, but they should be available to answer questions it's one of the things Fat Shark prides themselves on, they aren't the cheapest but they "stand behind the customer" and should help you out.
My guess based on what you described is some voltage regulator blew that is supplying "regulated" (around a set voltage) power to the rest of the components, but really probably best to contact their support to get someone in live chat or on phone who can help with some diagnostics or get you some sort of RMA/repair options.
Could also just be something like one of the pins on the back of the barrel jack for the battery input came dislodged from the PCB and could be resoldered on but again would contact them before doing anything too drastic.