Curious myself. Purchased a Used Radiopost servo a little while ago in the sale section here. Just recently installed it (was gonna put it in my pit box for a backup but decided to install it) and as soon as it's powered on it vibrates nonstop. Wheels centered or not, even with the vehicle off the ground. Have yet to get it on the track but wondering if it has one foot in the coffin already. Haven't seen another Radiopost servo do this. They're always one of the quietest servos out there. Only running 6.4 volts to the servo. Tried raising and lowering the voltage with no change.