Application of reduced bias levels to disc drive read elements during periods of inactivity

This invention relates generally to the field of disc drive data handling systems, and more particularly, but not by way of limitation, to a method and apparatus for reducing read element power dissipation during a disc drive idle condition to improve operational life of the read element. Apparatus and method for enhancing disc drive reliability by applying reduced read bias levels to read elements of a disc drive during an idle mode of operation. A preamplifier driver circuit applies an operational read bias signal of selected, nonzero magnitude to the read element to transduce data from a recording surface during an active mode. Once a predetermined period of inactivity occurs during which host data transfer commands are not processed, the disc drive enters the idle mode and the preamplifier reduces the read bias signal magnitude. The reduced bias level during the idle mode reduces thermal stress and electromigration within the read element while still allowing data to be transduced from the recording surface as the drive performs a dithering operation to move the head to different tracks on the recording surface.