Abstract: A method to accurately determine a defective servo burst written on a recording medium having plurality of tracks, each track containing plurality of position data portions. The position data portions include servo bursts capable of providing position error information, which can be selectively retrieved by a servo control system having a servo gate enabling signal. A first likely defective servo burst is identified by reading each servo burst, measuring corresponding position error information and comparing to a range of acceptable position error information. While disabling retrieval from the first likely defective servo burst, the position error information of plurality of servo bursts occurring after the first likely defective servo burst is measured. If the measured values are within the acceptable range, the first likely defective servo burst is concluded as the first confirmed defective servo burst.