Samsung DVD-709, Service Manual

Page: 68 / 179

Circuit Descriptions
Samsung Electronics 6-11
6-4 Servo
6-4-1 Outline
SERVO system of DVD is divided into Focusing SERVO, Tracking SERVO, SLED Linked SERVO and CLV
SERVO (DISC Motor Control SERVO).
1) Focusing SERVO
Focuses the optical spot output from object lens onto the disc surface. Maintains a uniform distance between
object lens of Pick-up and disc (for surface vibration of disc).
2) Tracking SERVO
Make the object lens follow the disc track in use of tracking error signal (created from Pick-up).
3) SLED Linked SERVO
When the tracking actuator inclines outwardly as the object lens follows the track during play, the SLED motor
moves slightly (and counteracts the incline).
4) CLV SERVO (DISC Motor Control SERVO)
Controls the disc motor to maintain a constant linear velocity (necessary for RF signal).
6-4-2 Block Diagram
Fig. 6-17
DISC
SLED M/T
HALL
PCB
LD
PD
SPINDLE M/T
CN1
HA1+
HA1–
HA2–
HA2+
SLED+
SLED–
AO
DO
CO
BO
FO
EO
PD
LD
F–
T+
T–
F+
SPINDLE
FOCUSING
TRACKING
SIC8
NJM2903
RIC1
KS1461
MIC1
TMP 93CS41F
SIC1
KS1452
DRIC2
KA3010D
DRIC1
KA3011D
+
›
!
x
“
0
&
t
1
2
8
7
!
@
#
@
%
^