Hi,
I have a Hitec HS-422 servo that has started jittering. Any idea what is causing this or how I might correct the jitter?
If the servo cannot reach the desired position and stabilize when powered with a proper energy source (and with no mechanical load) then you might have a problem with your potentiometer.Also, keep in mind that if your desired position is very close from the current position, then the servo might not be able to accelerate enough in order to reach it and will then jitter.
If you can test with two identical servos, to eliminate the possibility of a defective servo, this may help you troubleshoot by process of elimination.