Can anyone tell me if these receivers and transmitters are compatible? I was told they werre.
I have 2 of the transmitters and 2 of the receivers with ch 50 modules and ch 50 xtals in the receivers (Ibought them all together) but nothing is happening when I try to work the servos. Am I missing something. I have downloaded the manual for the transmitter and it is good for programming etc. but not much about initial startup.
I have used another transmitter and receiver and all works well.

These should work together. No set-up is required, it should work when the TX is switched on.

I would do some testing with a receiver that is known to be good.
Make sure you have the correct DC crystals.


I would suspect the RX's first, crash damage, it would be a longshot to have 2 bad TX's, but either could be at fault.

Both my T-7's still work fine.

If you want more information and more input, you may provide more information, such as who the manufacturer is. Not all of us are familiar with those part numbers.

they are compatable but the tx must be in ppm mode not pcm mode.this model transmitter can transmit in both modes depending on how you program it.check the manual on how to change modes or to see which mode is being used.It has been awile since I've used a 7 u but on the lcd it should show either ppm or pcm in small letters near the top somewhere.

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?

Thanks to all for your input.
I now have both transmitters and receivers working. The problem was that the xtals were not fully seated in the receivers.

I just purchased the FP-R168DF receiver which replaced the now discontinued FP-R127DF. I had a VERY hard time getting the crystal seated in the receptacles. The FP-R168DF is more compact and lighter than the FP-R127DF plus is both lo band and high band (not to mention it offers one more channel).

The only problem with the 168 is there was a rash of bad ones put on the market when they were first released.
I got one myself, when I sent it in to Futaba they told me they had some problems with them and sent me a new one.
I have only bought one more since then, I have been buying Hitec Supreme and Futaba PCM receivers.

PipeMajor- if they go in hard, maybe they won't fall out?

Missleman - Bad production run? What was wrong with the 168's?

Don't know what caused the problem but the one I got glitched real bad.(I spent a week rerouting wires and antena trying to get rid of the glitch) The service rep told me they had some problems with them and the new one they sent worked perfectly.

7 channels is enough for me....got one left over for missle ignition ;-) You have not seen a dogfight till you have seen an Estes equipped dogfight

Isn't launching pyrotechnics from a model airplane verboten by AMA?

Yes but they don't control my 20 acres yet.................

Might get interesting if one hangs up on the launch rail.[:@]

Been there, done that ;-)............It's all fun