You are sure that both transmitter and receivers are 75mhz? Looking at the Futaba site I only see a 27mhz version of that transmitter.

But OK, if they all are 75mhz be sure you have AM crystals. Be also sure you have a TX and a RX crystal (they have a 455khz difference).

And sometimes the 1st thing to do is get a fresh set of crystals. On the other hand, for almost the same price you have a simple GT2 transmitter or if you want sticks Futaba has a 2.4GHz stick transmitter for just 40 dollar.