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14. VCR Deck Operating Description
14-1 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.
14-2 Basic Configuration of Mechanism
As shown in Fig. 14-1, 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) (Capstan drive section)
PG Cylinder Capstan
FG
Control head
Cylinder servo Capstan servo FG
Cylinder servo
System control
Switch-Detect Cam slider Tension post Tape sensor
Tape loading
Reel brake REC-inhibiting SW
Pinch lever
Idle gear
FL
Cassette holder cam gear Loading motor
Reel sensor
(Front loading setion) (Loading motor drive section) (Front loading setion)
Fig. 14-1 Basic Configuration of Mechanism
Samsung Electronics 14-1
Reference Information
14-3 Main Mechanism and Functions
14-3-1 Tape Path System
The tape come out from the supply reel (S) of the video cassette runs through paths shown in Figs. 14-2 and 14-3,
and is taken up by the take-up (T) reel. (S stands for the supply reel, and T for the take-up reel, hereafter.)
At S reel side (tape enterance side of the cylinder) against the cylinder, a tension post to allow the tape surface to
contact with each head with a proper tension which assures stable running, an FE head which erases entire data
of the tape, and an S guide roller which restricts tape motion in upward/downward direction are provided.
In the same way, a T guide roller, audio head to record audio signals at upper side of the tape, control head to
record and reproduce a control signal at lower side of the tape, and an audio erase head to erase only the audio
signals and perform after-recording in parallel with the audio head are provided at T reel side. (tape exit side of
the cylinder).
The guide parts marked with asterisks (*) are equipped with the adjusting mechanism to stabilize the tape run-
ning or to record and reproduce the signals precisely.
* S slant guide *
S guide roller T guide roller
T slant guide
FE head
ACE head base
Cylinder
* ACE head position
adjusting screw
Pinch roller
RPS
Tension lever (released by No.9 guide
& tension post FF/REW mode) (pulled out at
RPS mode)
ACE adjusting screw Capstan motor
*
No.8 guide
Tilt
Azimuth ACE head position adjusting slit
(Insert slot-type screwdriver.)
Height
Fig. 14-2 Tape Path System
Cylinder T slant guide
S slant guide *
ACE head
Tension post
Capstan
No.9 guide
Pinch roller
FE head
No.8 guide
* *
S guide roller T guide roller
* show the locations to be adjusted.
Fig. 14-3 Guide Path System
14-2 Samsung Electronics
Reference Information
14-3-2 Reel Drive System
The reel drive system consists of a capstan motor as a drive power source, belt as a power transmission mecha-
nism, clutch mechanism, idle gears, and a reel disc. Selecting of forward rotation or reverse rotation is carried out
by an idle gear which changes its rotating direction according to rotating direction of the clutch holder.
Reel take-up torque is selected according to an operation mode.
In the record, playback, fps, rps modes, the reel take-up torque is controlled by the clutch mechanism, thereby the
tape fed by the capstan is taken up with a proper torque.
In the FF and REW modes, the clutch enters a direct connecting status in which the clutch mechanism does not
operate and the capstan drive torque is transmitted without reduction, so a high speed taking-up is enabled.
S slant guide
S guide roller T guide roller
T slant guide Video tape (Magneticside)
FE head ACE head
No. 8 guide
Cylinder Pinch roller
Capstan
No. 9 guide
Tension post Tape guide
Tape guide
S (Supply) reel disc
Idle gear Capstan belt
Clutch gear (Clutch mechanism) T (Tape-up) reel disc
Fig. 14-4 Reel Drive System
Samsung Electronics 14-3
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14-4 Basis of the Mechanism
14-4-1 Front Loading
Cassette IN
(1) When a video cassette is inserted into the cassette Switch Detect ON
holder and pushed furthermore, FL arm lever is
rotated by motion of the cassette holder. The rotation Microcomputer
of FL arm lever makes the horizontal moving of FL
drive slider. Loading Motor ON
(2) When the information of Switch Detect is Loading Motor
transmitted to the microcomputer, the loading motor
starts to rotate. Worm Gear
(3) The rotation is transmitted in a sequence shown Worm Wheel
below :
Loading motor - worm gear - worm wheel - FL Cam Gear
FL Cam Gear - FL Drive Slider - FL Arm Lever - FL Drive Slider
Cassette Holder
(4) The video cassette is horizontally moved. FL Arm Level
(5) The cassette tape is vertically moved. Cassette Holder
In this case, the cassette lid is opened.
Cassette Horizontal Motion
(6) The cassette tape is set on the reel disc, and loading
operation completes. Cassette Vertical Motion
(7) The cassette tape is loaded. Cassette Door Open
(8) The status becomes full loading.
Microcomputer
(9) When the cassette is out, the reverse steps of the
above procedure are carried out. Cassette Loading Complete
Tape Loading
Full Loading Mode
Fig. 14-5
FL arm lever Loading motor
FL drive slider
FL camgear Worm wheel
Fig. 14-6 Drive Transmission Path
14-4 Samsung Electronics
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14-4-2 Cassette loading/unloading Modes
When a cassette is entered in the VCR, the cassette is set on the reel disc by the front loading mechanism.
In this case, the tension post, loading tape guide, capstan motor, and the No.9 guide are positioned inside of the
tape in the cassette case.
Tension post T guide roller
S slant guide
T slant guide ACE head
FE head No. 8 guide
Cylinder Pinch roller
Capstan
No. 9 guide
Tape guide
S guide roller
Tape guide
S (Supply) reel disc
Idle gear Capstan belt
Clutch gear (Clutch mechanism) T (Tape-up) reel disc
Fig. 14-7 Cassette IN/OUT Mode
Samsung Electronics 14-5
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14-4-3 Tape Loading
A full loading system is employed.
In the full loading system, the tape loading starts at the same time when the cassette loading operation has com-
pleted and cassette has been mounted, and the tape is pulled out, wrapped around the cylinder and the mecha-
nism enters the stop status under this condition.
Cylinder T guide roller
S guide roller
Guide post
Guide post ACE head
FE head
No. 8 guide
Pinch roller
Capstan
Tension post
No. 9 guide
Tape guide
Tape guide
Fig. 14-8 Tape Loading
14-4-4 Playback Standby Mode
In the full loading system, the tape loading starts at the same time when the cassette mounting has completed, the
mechanism shifts to the playback position, and enters the standby status with keeping tape wrapped around the
cylinder.
In this case, tape tension applied to the cylinder is decreased to protect the tape and to prevent the tape from
scratches.
14-6 Samsung Electronics
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14-4-5 FF/REW Modes
The reels enter a free status by rotating the loading motor to go to FF/REW position.
In this case, the capstan motor rotates in colck-wise direction in the REW mode. The idle gear is swung rightward
or leftward according to the rotating direction of the capstan motor. As a result, the T reel rotates in the FF mode
or the S reel rotates in the REW mode, thus taking up the tape to the rotating reel.
S slant guide
S guide roller T guide roller
T slant guide Video tape (Magneticside)
FE head ACE head
No. 8 guide
Cylinder Pinch roller
Capstan
No. 9 guide
Tape guide
Tension post
Tape guide
S (Supply) reel disc
Idle gear Capstan belt
Clutch gear (Clutch mechanism) T (Tape-up) reel disc
Fig. 14-9 FF/REW Mode
Samsung Electronics 14-7
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14-4-6 Record/Playback Modes
When the record or playback button is pressed, the tape is fed by the rotation of the capstan motor.
In this case, a tension post touches the tape and braking froces created by the band brake linked with the tension
post is applied to the S reel, thereby stabilizing the tape tension. The tape fed by the capstan is taken up around
the T reel. The T reel is driven with a constant torque generated by transmitting rotation of the capstan motor to
the clutch mechanism.
S slant guide
S guide roller T guide roller
T slant guide Video tape (Magneticside)
FE head ACE head
No. 8 guide
Cylinder Pinch roller
Capstan
No. 9 guide
Tape guide
Tension post
Tape guide
S (Supply) reel disc T (Tape-up) reel disc
Clutch gear (Clutch mechanism)
Capstan belt
Idle gear
Fig. 14-10 Record/Playback Mode
14-8 Samsung Electronics
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14-5 System Control
In the VCR, complex mechanism, video, audio, servo circuits, etc. must be operated in specified timings matched
each other. The system control circuit performs entire controls for the VCR.
An automatic stop function is also provided to protect important tape if a trouble occurs on the complex mecha-
nism and the electrical circuits.
For this purpose, status of each part of the mechanism is always monitored with various sensor switches, and the
microcomputer controls collectively the unit so that the best condition is kept.
Moreover, the microcomputer controls signal switchings for each circuit according to the mechanism status.
Main microcomputer Loading motor control
(Voltage, direction)
Remote Remote Loading motor drive M Loading motor
control
broken safety tab
REC-inhibition
Mode sensor
(Detecting of mechanical mode position)
Mode SW
(Detection of cassette-in/cassette-out)
Cassette Tape in
Switch-Detect
Take up Abnormal reel retation
FF/REW speed control
T reel
sensor
Supply Abnormal reel retation
FF/REW speed control S reel
sensor
Key matrix Front button Current control
Input
Capstan motor control
(Speed direction) Capstan
motor drive M Capstan motor
FG pulse
FG
CTL pulse
AUDIO (Linear time counter)
IIC BUS Control
VIDEO
TUNER REC control
Cylinder motor control Cylinder
motor drive M Cylinder motor
POWER ON/OFF
REC mute FG/PG pulse
TV/VCR PG
FG
Fig. 14-11 System Control Block Diagram
Samsung Electronics 14-9
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14-6 System Control and Mechanical Operations
14-6-1 Mechanical Operation
The operation of mechanism is performed by rotation of the loading motor, and the transmission path of the oper-
ation is as shown in Fig. 14-12.
Loading Motor
FL cam gear FL drive slider FL arm lever Cassette holder
Cam slider Mode SW
No.9 guide
Loading drive gear S, T slider
Pinch drive lever Pinch lever
Tension drive lever Tension lever
S brake
T brake
Up/Down lever
Fig. 14-12 Transmission Path of Operation
Fig. 14-14 shows each mode and mechanism status in each mode concerned with the rotation of the FL cam gear
or cam slider shift. The mechanism operates as shown in Fig. 14-13 according to the timing chart in Fig. 14-14.
Note :
The Switch Detect is actuated by the rotational moving of Lever FL Arm-R and Switch on or off by insertion or
ejection of a cassette.
14-10 Samsung Electronics
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T slider assembly
Pinch assembly
Loading motor
S slider assembly
FL cam gear
No. 9 guide lever
Tension arm Joint lever
S brake (off) T brake (soft)
Idle lever assembly
T loading lever assembly S loading lever assembly
Loading motor
Loading drive gear
FL cam gear
Joint gear 1
Cam slider
T brake S brake
Pinch drive lever Tension drive lever
Joint gear 2
Fig. 14-13 Mechanical Operation
Samsung Electronics 14-11
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Fig. 14-14 Mecha Timing Chart (Kaiser-II)
14-12 Samsung Electronics
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(1) There are two STOP modes and two FF/REW modes.
1) STOP 1
This mode is performed when PB and FF/REW is not done for 5 miniute at power on.
The small load is given to S REEL DISC and T REEL DISC. And the cylinder motor is stopped.
2) STOP 2
This mode is performed when you press the stop button as performing FF/REW.
The large load is given to S REEL DISC and T REEL DISC.
3) FF/REW 1
This mode is performed when
OE The tape load is small during performing FF and reducing speed.