There is a now youtube video on how to fix this. You do need a tiny screwdriver and need to take the back off. There are several ribbon cables and one of them is for the metering. All the ribbon cable sockets have a tiny bar that you need to gently lift up, seat the cable end properly then push the bar back down. When the camera falls the jarring causes the bar of the metering cable to come unlatched and the ribbon cable comes loose. I didn't think of it at the time, but a tiny bit of electrical tape would help to hold it down. Anyway my D3200 is fixed. Yeah ! https://www.youtube.com/watch?v=uk9f5kXJcTA