I've confirmed that it does work with a gopro, so it's not defective. I still can't get the sjcam to work. I'm waiting for some adapters to come in so I can play around with it more.
Is there any settings I have to change on the camera? I don't have the gimbal connected right now so I'm just using the frame and cable that came on it but I don't get any video, I only have a hero2 so i can't even see if it's working properly.