I have purchased an AX2550, connected the wires, the joystick and did the bind on the R/C controller but still get the "u" with an underscore indicating no signal. What am I doing wrong? I thought this was plug and play with factory set up. If I do need to go into the programming how do I get there? Just connect to my computer and it will default? I know your product is top drawer stuff just not certain how to make it all work.
Underscore u means that either you have a signal, or that the controller is in RS232 mode.
If you are in rc mode and no radio signal is present, you should see the leds flashing "no ctrl"
Try resetting to defaults by pressing and holding the prog and set buttons as you reset the controller. When you see the leds flashing, release the buttons. then restart the controller.