| 摘要 |
PURPOSE:To prevent damage of a head or a disc by setting the permissible operating range of the magnetic head, and detecting the transfer of the head to the outside of the range with a different sensor from that of a servo system so as to detect a failure of the servo system. CONSTITUTION:A permissible limit sensor 9 and a position sense circuit 10 comprising a pair of sensors 9a, 9b such as photosensor detecting the moving permissible range of a magnetic head 4a are provided. When the sensor 9 detects the rear end of an arm 4b and the jumping of the head 4a is detected, a detection output is applied to a power amplifier 6 via a position sense circuit 10 to stop a liner motor 4, a detecting signal is given to a liner motor control circuit 8 and the shift of the head 4a is corrected. Thus, a failure of the servo system is detected and the damage to the head and disc due to the failure is prevented. |
