I bought my P2 over in 2014. I have always had video transmission problems, poor quality more that 750 feet. I want to try another transmitter and purchased a immersion 5.8GHz 200mW. I think I may have accidentally connected to he power in reverse polarity. The immersion power wire is switch from my previous noname transmitter. I think this because my CAM port has blacken film around the base of the CAM plug and base of CAM Port. Using a multi meter I have tested the wires for power. Nothing. Any thought on what I should try?