| 摘要 |
<p>PURPOSE:To solve an abnormal state, by providing a control circuit which performs forward/backward rotation control over a motor according to the output signal of a head position detector, and returning a head to a reference operation position which is the lock position of a cam when the head stops moving and shifts in position. CONSTITUTION:If a failure in positioning (causing the output of a photoreflector 13 to rise to[H]) occurs even one and a half seconds (enough for a rotating disk 5 and a cam 6 to have one turn) after a motor 1 is driven forward, it is considered that an obstacle is caught by a head driving mechanism, so the motor 1 is driven backward (toward a position STOP) for one and a half seconds to return the head to the position STOP. At the stop position STOP, the head 18 is locked mechanically, so the head 8 is returned to the position STOP in one and a half seconds without fail wherever the head is. Through said operation, the obstacle is removed normally. If a failure in positioning (causing the output of the photoreflector 13 to rise to[H]occurs even after the motor 1 is driven backward for one and a half seconds, a decision on a fault is made because the head is normally returned to the position STOP without fail, thereby displaying that on a display circuit 16.</p> |
