ORIGINAL: mnfly
I have tried both transmitters with another receiver that I know is good and still no results. The receivers have the red dot so i know they are high band and on ch. 50.
I downloaded the manual and reset to default settings and to PPM.
I have a 7UAFS myself with R127DF RX and it is a fine combination. Since you have made certain the TX is in PPM mode and it failed to operate with a "known good" RX it must mean the TX's are bad
OR that the "known good" rx is not Futaba PPM compatible.
As for the RX's being hi/lo types, even if wrong they would still work at close range. Are the crystals dual conversion types?