VCR Deck Operating Description
8-5 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)
RemoteRemoteLoading motor driveM Loading motor
control
broken safety tab
REC-inhibition
Mode sensor
(Detecting of mechanical mode position)
Mode SW
(Detection of cassette-in/cassette-out)
STEREO
Tape
Stsrt sensor
Tape stsrt sensor
Tape end LED
Abnormal reel retation
Take up
FF/REW speed control
T reel
sensor
Abnormal reel retation
Supply
FF/REW speed controlS reel
sensor
Key matrix Front button
Current control
Input
Capstan motor control
(Speed direction)Capstan
M Capstan motor
motor drive
FG pulse
FG
CTL pulse
(Linear time counter)
AUDIO
IIC BUSControl
VIDEO
TUNERREC control
Cylinder motor controlCylinder
M Cylinder motormotor drive
POWER ON/OFF
REC muteFG/PG pulse
TV/VCRPG
FG
Fig. 8-11 System Control Block Diagram
8-9 |
ACEC
