The needle tip of the microsensor is vibrating or not moving smoothly when I try to insert it in the sample with the Manual Micromanipulator. What can I do?

Please check if the Manual Micromanipulator is placed on a flat, clean surface, and all four non-slip rubber bumpers on the base plate are touching the surface.
Then make sure all screws - of the sensor holder, and tilting platform - are closed tightly and that your sample is positioned immobile and vibration free on a hard surface. Also make sure your sampling area is devoid of any hard substrates that cannot be penetrated by the steel needle, such as stones, debris-pieces or bones.