Method and apparatus adaptively adjusting power levels of a data transducer in a data storage device. In some embodiments, an initial power value is applied to a powered element of a transducer to write user data from a host device to a rotatable data recording medium. An exception condition is declared responsive to a measured parameter. The transducer is used to read data from an evaluation track using a range of different input power values for the powered element. A different, new power value is selected for the powered element responsive to an error rate associated with each of the range of different input power values, with the new power value being lower than the initial power value. Thereafter, the new power value is applied to the powered element during a subsequent writing of user data to the rotatable data recording medium.