| 摘要 |
PURPOSE:To surely eliminate a locked groove, by the constitution that an arm is moved compulsively, if the arm is not moved after an arbitrary set time, in an arm control circuit of a video disc player. CONSTITUTION:An output from an arm servo circuit 4 is supplied to a timer circuit 27, and when a signal is supplied to an integration circuit 27-2 via an OR circuit 27-1, a locked groove not eliminated is caused, and if an arm is not driven for a specified time, the integrating circuit 27-2 is reduced to a low level, this change is inverted at an inverting circuit 27-3 and differentiated to supply to a drive circuit 5 for driving. At normal operation, the output of the circuit 4 is taken for logical sum with the output of an oscillator 28 at an AND circuit 29 and inputted to the drive circuit 5. When a signal enters the drive circuit 5, a drive transistor 5-2 turns on and an arm motor 6 is driven. |
