Can someone help me with my TX/RX? It's not working... - RC Groups
Thread Tools
Aug 18, 2003, 09:00 AM
Registered User
TurboRacer's Avatar

Can someone help me with my TX/RX? It's not working...

Ok, I just bought a Crazy Max, and have everything I need now to fly it, or so I thought...

I have a Futaba 9cH for my TX. Running on channel 39. I have a Hitec feather single conversion negative shift RX for the max. I bought from Servo City a Hitec Single Conversion crystal #39.

I swith the TX on, and plug a bettery into the RX.. The servos twitch at the initial power up, but when I move the sticks, nothing moves. If I turn off the TX while the battery is still plugged in to the RX, then turn on the TX again, the servos twitch as the TX comes on, so they're getting some type of signal...

Is my TX not compatible with single conversion? Or is there something I have to change on my TX to make it work with that RX?

I have a Berg 5 RX for my Piccolo pro, and it works fine with this TX. But the Hitec does not work for some reason..

Anyone have any ideas? Any suggestions or info would be greatly appreciated!

Sign up now
to remove ads between posts
Aug 18, 2003, 10:31 AM
Registered User
The Tx must be compatible with single conversion, the Berg is a single conversion Rx.

Check that the servos are plugged in correctly. You haven't accidently switched the Tx into PCM mode have you ? Try it using exactly the same model memory as the Piccolo and see if it does anything.

Alternatively you may just have a dead Feather.

Aug 18, 2003, 10:42 AM
Registered User
TurboRacer's Avatar
Originally posted by steve lewin
You haven't accidently switched the Tx into PCM mode have you ?

One of my friends asked the same thing, and truthfully, I can't remember! I think it may be. I will check when I get home tonight. I hope that's the problem!! Thanks buddy.
Aug 18, 2003, 12:45 PM
Registered User
Single conversion, double conversion, doesn't matter. The signals are the same.

The term "conversion" is used in regards to the filtering the receiver does when it receives a signal. A single conversion receiver filters the signal once. A double conversion receiver filters the signal twice. That's it in a nutshell.
Aug 18, 2003, 02:24 PM
Registered User
vintage1's Avatar
Double conversion applies to the reciever only. You need a different Crystal in a doubvle convesrion reciever: Apart from that there is no incompatibility issue wih the transmitter. So thats not it. Well unless you have been sold a #39 double conversion crystal by mistake, Check that.

PCM is a modulation issue, and both transmitter and receiver need to be compatible with whatever standard is in use. A non PCM receiver will not do anything uif a PCM mode transmitter is used. Futaba transmitters have selectable PCM/non PCM modes. Check this.

There is an issue on US sets with positive and negative frequency shifts. I don't think this applies to Futaba TX Hitec RX.

Try some obvious things first like removng the ESC and checking using a normal RX pack on the receiver. Near dead batteries can cause the effect you are noting.

If that still doesn't work, try substituting a different receiver - taking teh whole shebang back to whereyou bought the reciever and letting them sort oit may be the fastest approach.

I hope you didn;'t plug the servos in backwards...
Aug 19, 2003, 08:12 AM
Registered User
TurboRacer's Avatar
Thank you guys!!

It was the PCM/PPM issue. It was switched to PCM.

Now the RX works perfectly.

Thanks again!!!