captnem

My Feedback: (1)

I have a Futaba 7uap transmitter and an R129DP receiver. The system range checks ok. When I start my engine on the airplane, the servos start moving all over the place. If I trottle back to idle, it gets a little better. But when I run the engine up, Things get jittery, sometimes the trottle servo will go from half to full to half and so on. Please Help! Would just sending in the receiver to Futaba to get checked out, be worth it? Thank you!!

-Matt

TLH101

My Feedback: (90)

If this with a gas engine, you may be getting RF noise from the ignition system. If it is a glow engine, it is most likely a vibration issue.
If you suspect an ignition issue, try to move anything related to the ignition system( switch, battery etc) as far as possible from the radio system. If you throttle servo is close to the engine, try unpugging it and see what happens.
Fist thing to check if you suspect vibration is the switch. plug the battery into the receiver directly and see if it clears up. If not, find a way to make the receiver vibrate without the engine running, like with a palm sander or electric pencil. See if the servos jitter then.

JohnMac

Above and beyond what Terry suggests, try the Rx crystal. Also look for metal to metal contact as elecrcal noise can be generated.. Is the clevis on the throttle arm metal? This is a common problem.
If its none of these things, check the battery for vibration, you can have a bad contact inside.
Regards,

John

piper_chuck

My Feedback: (12)

I'd also suggest looking for metal to metal contact. If you can't find any, try another receiver. If the same problem happens, you know your receiver is ok. If so, try changing the other components, one by one, until the problem goes away.