HD-3001HB standerd servo problem

[sheko_2000]

hello,



i just received 5 HD-3001HB standard servos from HK

unfortunately one of them is dead but the others are working but in a weird way



1- speed is ok

2- torque is ok

3- centering is ok and average for 1 servo



the problem here that i keep hearing that servos' motors are keeping buzzing in the idle mode of the centard position i have to move the Tx stick a little bit to make this sound stops (its sounds like ZZZZZZZZ) and i feel the servo is vibrating from inside



am worry about the servos' gears



is this a normal behavior ?

[RCModelReviews]

An unloaded servo should not buzz around center when the sticks aren't being moved.

That buzzing means that the servo amp is trying to move the servo to a new position but it's not driving the motor hard enough to actually turn the gears.

This can mean that either the gears are binding slightly or that the servo amplifier isn't very good and has a rather "soft" deadband with inadequate hysteresis.

They'll probably work fine (if they seem okay in all other respects) but they may draw more current than a "better" servo.