Sansui FR-D4 - Block Diagram; Operation

FR-D4
1. BLOCK DIAGRAM
c
START/STOP Swol
REPEAT swo2 |
SPEED
SELECTOR 33/45 SwO3
T|
COMPUTER 63
CONTROL SECTION
$-0030 °
- = 33/45
Ico?
ICO2a, 4 4A. |, DDMOTOR
De > KO MicRO- Coze START/STOP CONTROL CIRCUIT
H REPEAT
ack
LED702
ICO2c
RECORD SIZE
SELECTOR 30/17 Swo4
WAVE SHAPING CIRCU
\Co4c, d D>
TRI3 awit
TONEARM POSITION SENSOR
A-SENSOR
Tonearm Descending
position(30/17) Detection
‘ C-SENSOR
Lowest Position
O-SENSOR |
Highest Position (
:
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ARM LIFTER POSITION SENSOR
_ TROZ
ASTABLE MUL TIVIBRATOR
ICO4a, b, ICO2d
(®LeD701
MICROMOTOR CONTROL CIRCUIT
(C05a~d, TRO6~ 11
|_| B-SENSOR ; CW ove
| Record End Detection i ae
RETURN
LEAD IN
ARM LIFTER
cw
cow
“CLOCKWISE
COUNTER CLOCKWISE
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2. OPERATION
2-1. Construction of Full-Auto System
(See Block Diagram)
The full-auto system adopted in this model is composed of 1) Driv-
ing mechanism Ass’y for tonearm and arm lifter (here after called
driving mechanism ass’y), 2) Electrical control section governing the
driving mechanism ass’y.
Arm position sensor (A-sensor, B-sensor) and lifter position sensor
(C-sensor, D-sensor) are attached to the driving mechanism ass’y and
detecting vertical and horizontal position of tonearm, The control
section composed of one chip micro computer (MB8844) and peri-
pheral circuits controls 1) rotation of DD Motor 2) lead-in, return
and repeat of tonearm function 3) up or down of lifter operation
Corresponding to the states of arm position sensor, lifter position
sensor and operating switch.
2-2. Movement of driving mechanism ass’y and
function of arm position sensor, lifter posi-
tion sensor.
1. Movement of driving mechanism ass’y (See Fig. 2-1, 2-2)
The configuration and side view of driving mechanism ass’y and gear
train from micro motor are indicated in Figs. 2-1, 2-2.
The torque of micro motor to drive tonearm and arm lifter is pro-
pagated from worm gear Ass’y => gear (1) =>gear (3) = friction pul-
ley = friction disc > plunger > clutch plate that clutch plate starts
rotation. Since clutch plate and friction disc are fixed to plunger,
rotation of friction disc is directly transmitted to clutch plate.
Clutch plate is depressed to the gear (2) while plunger solenoid
being OFF, however, when it becomes ON, the clutch plate is re-
leased from gear (2) then depressed to TA drum. Therefore while
plunger solenoid being ON tonearm is driven, and it being OFF arm
lifter and brake shoe are operated to transmit the micro motor tor-
que from clutch plate > gear (2) > lifter cam.
As brake shoe is depressed to TA drum while arm lifter being arised,
tonearm is restricted not to move excessively by its inertia during re-
turn and lead-in operation. When the fifter is completely lowered,
brake shoe is released from TA drum that tonearm is free from the
brake.