Hey there, so I have had this drone built for me a while ago and everything has been going great, I have replaced 1 motor and done a little in beta flight and the video feed is not working...I have gone back and resoldered all the wires and nothing has changed, yes I am on the right channel...basically, all I get is mad fuzz however the goggles do seem to be connecting to the VTX, just no video...see the link for photos...the build I received is a very old style build which confuses me a bit... https://photos.google.com/share/AF1...?key=N01PNll4MURkR1N3N2VUNFYycXgyZFhFa1FtcUd3
I am very new to this...maybe a noob suggestion but my camera does not have osd wires, and an enabled osd in betaflight cause I don't know what I'm doing...could that be the problem?
Seems likely to me the VTX fried at some point (it happens pretty often if don't have an antenna hooked up to VTX or it gets knocked free and the VTX is trying to transmit still can overheat itself cause no where for that amplified signal to go out of the thing). Regarding the OSD question there's no dedicated line or special thing regarding adding OSD except having a FC with chip on there that supports doing the OSD rendering on the vid feed. Basically way that works is the vid signal is a analog video feed (like old school RCA cable with yellow wire), that analog vid signal gets sent into the FC, the FC "looks" for the frame start/end markers in the analog signal and just adds in extra data "on top of" the existing analog vid signal and then pipes that out through the v-out (assuming has v-in for vid in and v-out on the FC or else definitely doesn't support OSD overlay).
Generally speaking if a VTX is working fine and the analog vid signal coming into it is not present or garbage then the VTX will just transmit a black screen so usually in that case know there is something wrong with the vid signal coming from the camera or FC. If the vid signal looks like fuzz then usually means some issue with either the VTX itself, the antenna or the channel (the last of which you ruled out).
You could try lowering the output power on the VTX since it is working for a few seconds reducing the amplified power would reduce heat on it and may stop it from overheating and shutting down, also potentially adding heatsink could salvage it but would be suspect of the VTX at this point.