DX7 w/Futaba Servos - Servos buzzing at center stick

[NUMB-LOCK]

I'm setting up my TREX 600. My Tx and Rx batteries are fully charged. I am at the point of using the sub trim to set my servos, however, at center stick, 1 or 2 of them are buzzing. These are Futaba S9252 servos.

Any thoughts?

Thanks,

Bob I.

[kgfly]

Not uncommon for digital servos to buzz a little as they track small variations in the signal from the Rx. This explanantion from XPS is quite good:

An interesting fact -

Digital servos do not "hum" by nature. With our system, they make no noise while idle unless there is a load on the control arm. The reason why other radios systems cause these types of servos to hum is the pulse conversion stability. "Normal" (non-digital) servos do not respond unless there is at least 3us (three microseconds) of change in the servo pulse width. This "slop" of 3us is very common in standard radio systems. Digital servos are so accurate that they respond to as little as a 1us change in the servo pulse width. This means that a standard radio system is causing a digital servo to move around constantly while just sitting still in what is considered to be an idle position. Our radio system has a servo pulse width variation of +/-10ns.

I guess your Rx has a pulse variation that is right on the boundary for S9252 servos so one or two are responding while the others don't quite see it.