Abstract: A plurality of motors are arranged on opposite surfaces of a single magnetic base plate such that they are magnetically isolated from each other by the base plate. Such an arrangement prevents the motors from magnetically interfering with each other and, thereby, allows them to be positioned as close to each other as possible, in order to cut down the overall size of an apparatus in which the motors are installed.

Abstract: A record disc playing apparatus has a tone arm position detecting device which comprises a position detection part comprising a plurality of reading elements aligned in line, a code part comprising a plurality of rows of code patterns shifted in the direction of alignment of reading elements and extending along substantially perpendicular directions to the alignment direction of reading elements, and an encoder which is supplied with the output signal of the position detection part and produces address signals according to the relative position of the position detection part and the reading part. One of the code part and the position detection part is fixed and the other unitarily undergoes displacement with a tone arm of the record disc playing apparatus.

Abstract: A record disc playing apparatus comprises an address signal generating unit for generating address signals corresponding to horizontal rotational angular positions of a tone arm, a device for generating a rotational angular velocity signal corresponding to the rotational angular velocity of the tone arm, a circuit for controlling the rotation of a motor for driving a turntable, a control device supplied with the address signals and having a memory device from which is from which read out information corresponding to the addresses indicated by the address signals, and an attenuation circuit supplied with the rotational angular velocity signal and operating with an attenuation quantity, with respect to the rotational angular velocity signal, which quantity is varied by a signal from the control device. The rotational angular velocity signal corresponds to the quantity of any eccentricity of the record disc. The control device producing as output signals based on the information thus read out.

Abstract: A pickup arm is equipped with a photo sensor assembly for detecting non-recorded portions on a disk. The sensor is located in such a position that horizontal distance between the stylus tip and the detecting point of the sensor measured in the direction of the radius of the turntable is substantially constant throughout the possible rotational angle of the arm. The rotational angle of the arm is measured and is modified by a given angle corresponding to the above mentioned distance. When this distance deviates from a standard value on replacement of the same with another, the variation may be readily corrected by manipulating a potentiometer. Prior to performing an automatic playback, the disk is scanned by the sensor and signals indicative of the arm angles corresponding to the non-recorded portions are stored.

Abstract: A record disc playing apparatus comprises a horizontal drive motor for imparting a horizontal rotational force to a tone arm an address signal generating device for generating an address signal corresponding to a horizontal rotational angle position of the tone arm and a control device including a memory device for storing the magnitude of an inside force to be produced on the tone arm in correspondence with the horizontal rotational angle position of the tone arm. The address signal generating device supplies the generated address signal to the control device. The control device reads out the magnitude of the inside force from the memory device corresponding to the supplied address signal, produces a signal for cancelling the inside force at the rotational angle position of the tone arm corresponding to the read out magnitude of the inside force and supplies the same to the horizontal drive motor.