| 摘要 |
PURPOSE:To switch the working current to the holding current with high stability after a stylus tip reaches assuredly a record disk without using a timer or a mechanical switch, by detecting first that the tracking errors reach the prescribed level after a solenoid is excited by the working current. CONSTITUTION:When a transistor (TR)43 is turned on, a collector current superposed on the holding current of an electromagnetic plunger 16 flows to the plunger 16. This plunger 16 is excited by the working current. A stylus tip 19 touches the surface of a record disk, and a tone arm 1 and a shutter 10 are moved with the shift of the tip 19. Thus the tracking errors increase. When these errors exceed the prescribed level which is set by the voltage value of a voltage source 33, a comparator 34 produces a high potential output. The output given from a Q output terminal of an FF31 is set at a low potential, and a muting relay 41 is not excited. Thus the muting state is released for the output of a pickup cartridge 6. At the same time, the exciting current of a plunger 16 generated by the TR43 is cut off. Then only the holding current produced by a TR35 flows to keep the position of an arm lifter 13. |
