Performance test method of head gimgal assembly with precise positioning actuator

Abstract

A method of testing a performance of the HGA has a step of writing information from the at least one thin-film magnetic head element onto a magnetic disk with driving the actuator for displacement by applying an alternating drive signal to the actuator, a step of reading out the information of at least one rotation of the magnetic disk by the at least one thin-film magnetic head element without driving the actuator for displacement, a step of storing the information read-out from the magnetic disk as a read-out information along a disk-rotating direction, a step of moving the HGA toward an off-track direction by a predetermined distance, a step of repeatedly executing the reading, storing and moving steps to obtain two-dimensional read-out information along the disk-rotating direction and the off-track direction, and a step of determining, from the two-dimensional read-out information, an off-track position where the read-out information becomes maximum at each position along the disk-rotating direction, the determined off-track positions being recognized as displaced positions of the actuator in response to the applied alternating drive signal.