Abstract: A method for calculating an amount and determining a position of an eccentric mass existing in a rotary head apparatus of a fixed shaft type, and to an apparatus for calculating and determining the same is disclosed. The method for calculating an amount and determining a position of the eccentric mass of the rotary head apparatus of the fixed shaft type and the apparatus for calculating and determining the same, are very accurate and credible. Accordingly, the rotational vibration of the head apparatus can be largely reduced through a balancing utilizing the eccentric mass calculated by and determined by the above-mentioned method and apparatus.

Abstract: A head drum assembly for use in a digital video cassette recorder includes a miniaturized transformer which has a rotor piece provided with a groove and a stator piece provided with an identical groove as that of the rotor piece groove, wherein the groove of the rotor piece is commonly used for a pair of heads.

Abstract: An apparatus for testing components to be inserted in a video cassette recorder or digital video cassette recorder includes a base provided with a pair of guide rails, a stationary plate, a first and a pair of second driven plates moving along the guide rails, and a capstan motor holder on which a capstan shaft and a hinge pin are mounted. The pinch roller lever assembly is provided with a pivot arm pivotably mounted to the hinge pin, a pinch roller rotatably mounted on the pivot arm, a lever and a coil spring, wherein one end of the lever is rotatably fixed near the pinch roller on the pivot arm and the other end is provided with a protrusion and a substantial ellipse-shaped ring, both ends of the coil spring are secured to the protrusion of the lever and the boss of the second driven plate, respectively.

Abstract: A head drum assembly, for use in a video cassette recorder, comprises a rotary drum provided with a circumferential side wall and at least one opening provided thereon, a pair of heads each of which is provided with a head chip and a head base, a guide member for guiding the head base in a direction that is substantially parallel to the rotating shaft, and an electromagnet for moving the head in the direction parallel to the rotating shaft while the head chip is in contact with the magnetic tape. The rotary drum is held rotatable by a bracket. The heads are disposed 180.degree. from each other on an inner bottom surface of the rotary drum, the head chip coming in contact with a magnetic tape partially wrapped around the rotary drum through the opening. The guide member is secured on the inner bottom surface of the rotary drum, guiding the head base in the direction parallel to the axis of the rotary drum.

Abstract: A signal transmitting device for use in a head drum assembly includes a fixed shaft, a rotary drum rotatably mounted around the fixed shaft, at least two magnetic heads arranged on and attached to the rotary drum with a same angular separation therebetween, a same number of laser diodes as the magnetic heads, each of the laser diodes being capable of converting electrical signal produced in the magnetic heads into optical signal and emitting the optical signal toward a center of the fixed shaft and a photo diode adapted to receive the optical signal from one of the laser diodes and to convert the received optical signal into electrical signal.

Abstract: Disclosed is a rotary head drum for a VCR having an improved structure for connecting a VCR head to a rotary transformer. A printed circuit board having an electro-conductive pattern is mounted on a head base. The first end of the electro-conductive pattern is electrically connected to a wire of the video head by means of soldering, and an electro-conductive adhesive is provided at the second end of the electro-conductive pattern. The head base is attached to the bottom surface of an upper drum by a screw. After mounting a fixing plate on an upper rotary transformer, a connecting wire extending from the upper rotary transformer is fixed to a bottom surface of a horizontal portion of the fixing plate by soldering. Next, the upper rotary transformer is fixed to the bottom surface of the upper drum. The VCR head does not require a soldering work while the upper rotary transformer is being assembled, thereby improving work efficiency.

Abstract: An apparatus for testing components to be inserted in a video cassette recorder or digital video cassette recorder includes a base provided with a pair of guide rails, a stationary plate, a first and a pair of second driven plates moving along the guide rails, and a capstan motor holder on which a capstan shaft and a hinge pin are mounted. The pinch roller lever assembly is provided with a pivot arm pivotably mounted to the hinge pin, a pinch roller rotatably mounted on the pivot arm, a lever and a coil spring, wherein one end of the lever is rotatably fixed near the pinch roller on the pivot arm and the other end is provided with a protrusion and a substantial ellipse-shaped ring, both ends of the coil spring are secured to the protrusion of the lever and the boss of the second driven plate, respectively.