Vcr Deck Operating Description - Samsung SV-DVD50 Service Manual

8. VCR Deck Operating Description

8-1 Features of Mechanism
The following items describe features of the mechanism in VCR.
(1) This VCR uses 3-motor system consisted of a cylinder motor, capstan motor, and loading motor.
A capstan motor is used to drive the reel and the driving force is transmitted throuch the belt capstan.
The cassette loading, tape loading, and mode shift operation are performed by the loading motor.
(2) The time duration from cassette-in to picture appearance is shortened by employing the loading drive mecha-
nism (automatic transferring operation from the cassette loading to the tape loading by rotating the loading
motor continuously), and by increasing the speed of the tape loading, etc
(3) Employment of the full loading system shortens time required to shift the mode such as STOP to PLAY-BACK
picture display.
(4) To simplify wiring and others, the electrical components relating to operation of the mechanical deck, such as
sensors, mode switch, servo microcomputer, etc. are mounted on the PCB arranged all over the bottom side of
the mechanical deck.
8-2 Basic Configuration of Mechanism
As shown in Fig. 8-1, the mechanism of VCR is configured with five main blocks, and each operation is precisely
controlled by the microcomputer built in the system control section.
First, load a video cassette tape in VCR :
(1) The cassette is automatically set on the reel disc.
(2) The tape is pulled out from the cassette, and wrapped around the cylinder.
(3) The cylinder turns in a constant speed rate synchronizing with the vertical Sync. signal of video signal.
(4) The tape runs in synchronization with cylinder rotation and traces the video tracks precisely.
(5) The running tape is taken up by the reel, the tape feeding side is given with a proper tension so that tape is not
slacked.
The above series of operations are performed under control of the system control section. The system control sec-
tion also sends commands to each mechanism according to the operation buttons, thus the VCR is designed so
that various operations such as recording, playback, special playback, FPS/RPS, and FF/REW, etc. are correctly
performed.
(Cylinder section)
Cylinder servo
Start sensor
Cassette holder
(Front loading setion)
Samsung Electronics
Cylinder
PG
FG
Cylinder servo
System control
Cam slider
FL
cam gear
(Loading motor drive section)
Fig. 8-1 Basic Configuration of Mechanism
(Capstan drive section)
Capstan
Control head
Capstan servo
Tape loading
Pinch lever
Loading motor
FG
Tension post Tape sensor
Reel brake REC-inhibiting SW
Idle gear
Reel sensor
(Front loading setion)
8-1