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?

No one?

You might have activated th-speed, is assigned to a switch?

I'll have to check that out, Thanks.

Found it. Wasn't assigned to a switch but was turned on by throttle movement. Wrong number entered in mode one. Thanks!

Glad you got it sorted. I miss my 3PK - favorite transmitter

Same here. Hope it doesn't die before me.

Happy that you found the solution! Also love the radio, except for those huge receivers.