I have a Futaba 3PK than has a dark block showing on the display with the letters "TSP" and the power indicator light is blinking. I looked thru the owners manual and there's nothing said about this situation. It only does it when I switch between two different modes. Is it possible that the one mode is going bad? After a minute or so, the power light quits flashing and dark block goes away. Anyone else ever have this come up?