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Servo  Stopped  Working

A robot servo may have been damaged and/or burnt-out for a few reasons.  The following points are common issues that lead to damaged servos.  For additional information about how servos work, we highly recommend following the provided Servo Tutorial in the learn section by clicking here.

EZ-Robot servos are designed to fail if there the load is too high.  This is no different than you, as a human, attempting to hold yourself in positions that strains muscles.  A servo giving out is the same as a muscle giving out.  The safety release of a servo is inside itself, to prevent damage from affecting other components, such as the EZ-B or battery.

  1. Improper calibration will cause servos to hum/buzz while holding the robot's default standing position.  Ensure the latest ARC (formerly EZ-Builder) software and EZ-Robot project is loaded for the robot.  Also, ensure the calibration process has been executed and the correct saved calibration file is loaded.  An incorrect calibrated robot increases the chance of servo failure.
  2. Moving a servo when something is obstructing it from moving.  When a servo is given a command to move but it is unable to physically move into the desired position (e.g. telling JD to move his claw to 180 degrees) will damage the servo.  Servos do not have a method of reporting that they are unable to move.
  3. High amount of stress/weight can damage servos.  The concept is similar to the first point, as weight prevents the servo from moving, this will damage the internals of the servo.  The heavier the load, or the further the load is away from the servo, the more stress there will be on the servo.  If you are experiencing damaged servos, consider lightening the load.
  4. Putting strain or pulling the servo cable will result in the cables fraying or breaking which will result in a short circuit.  A short circuit is protected by the EZ-B fuse, but will still create a burning smell and the heat may melt the plastic housing of the servo.  To prevent this, make sure servo cables are loose and not bent at sharp angles.