A couple things with Futaba and buddy box setups. First, the Transmitting box has to have the trainer function enabled. If you go through you manual and look for the trainer, if the sitch shows INH, the buddy box isn't going to work. Change the function so the switch shows OFF and if the transmitting box switch is thrown it will show ON.

The Buddy box must be in PPM Mode. The Buddy box should remain powered off, the power is supplyed by transmitting box. There is no need to remove the antenna and Xtal in the buddy box, they don't work when setup as the buddy box, only the gimbles work.

Some Futaba TX's will not allow Expo and end points to work with a buddy box, only raw gimble input. My 9C does allow the expo and end points to work on all but the throttle. My son's 6eax 72mhz just transmits the raw gimble movements of the buddy box TX without modification. What a susprise that was, and this was conformed by Bax last fall. I don't know if the 2.4ghz 6Eax works the same. No test bed to work with.

Your experience with not powering on the trainer box is correct. The power is supplied to the trainer box, but not RF capibility.

My suggestion is to get a Futaba cord that matches your setup. Set the transmiting TX up correctly and all will be as well as the mix allows.

Don