RE: New JR Syn Pro Radio Issue????
It sounds like Bob nailed your problem. That kind of servo performance is quite typical of a loose metel to metal connection...and it is vibrating and giving interference only when the motor is running. Check to be sure every metal to metal screw, nut, etc is very tight. Also check to see that you have not changed the stock arrangement of linkages, etc, and thereby created a metal to metal contact somewhere. Another way to locate the problem is to touch suspected components with a handy screwdriver or any other metal tool...trying to make the interference happen while the motor is not running. Curing the problem will be easy...once you locate the offending part(s).
good luck.
Jim