RE: Servo chatter
EZ Fly
OK, this gets me thinking it you have the same problem with 2 different servos. If you move those servos to another radio system does the problem follow? If the answer is no then I would begin to look at the radio. Could the pot on the stick of the transmitter be the problem? If you move the servo to another function on the radio does the problem follow? If you hold the stick on the TX in a different position does the servo chatter in the new fixed position?
Do you have a scope? It would be interesting to look at the pulse width going to the servo to see if that is changing. And to look at the modulation line in the TX.
I know most people do not have a scope. I'm just trying to look at this to see if the problem is in the servo or some other place in the system.
I hope this helps,
Pete
EDIT
I went back and re-read the first post, that you tried different transmitters and receivers. Next I would try plugging the servo directly into the receiver with the battery plugged into the receiver. This makes the most simple set up. If no chatter then put in the extentions. It could be as simple as the contacts on the extention being not quite good enough.