where was the plane and radio stored?moisture from condensation can cause all kinds of corrosion inside tx and rx,were the batteries in the plane and were they kept charged the past 8 months.there is also the possibility of black wire which is the negative leads off of both battery packs turning black instead of copper.sound like a check up by a service center would be the best thing to do if nothing has changed in your set up since the last time you flew.