Sony MZ-E30, Service Manual

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Fig. 8-1 Outline of Servo Circuit
As shown in Fig. 8-1., the servo circuit is composed of the RF amplifier (IC501), DSP/digital servo (IC601), system
controller (IC801), and the servo driver (IC551).
When a playback disc is played, the servo circuit operates in the same way as the CD player.
The focus and tracking servos A/D convert the error signals output from the RF amplifier inside the DSP/digital servo
(IC601), and perform servo calculation and correction. They then convert the signals to 2 fs (fs=44.1 kHz) PWM wave and
output them to drive the focus and tracking coil using the servo driver (IC551).
The spindle servo sends the measured period of the EFM frequency divided signal obtained from the RF signal using the DSP/
digital servo (IC601) to the system controller, generates the spindle error signal inside, and controls the rotation of the spindle
motor via the servo driver. The sled servo A/D converts the tracking error signal, sends the data to the system controller, and
generates the control signal of the sled motor control (IC803). The sled error signal is generated from this control signal in the
sled motor control (IC803) in the next stage, and used to control the rotation of the sled motor via the servo driver.
When the MO disc is played back, only the spindle servo in the servo circuit differs from when the playback only disc is
played back. In the case of the playback of the playback only disc, the measured period of the EFM frequency divided signal
obtained from the RF signal is used. In the case of the MO disc, that of the frequency divided signal obtained from the ADIP
signal recorded in the groove area is used.
In this unit, the digital servo composed of the RF amplifier (IC501), DSP/digital servo (IC601), and system controller
(IC801) controls focus, tracking, sled, and spindle. RF level adjustment and ABCD level adjustment are performed
automatically immediately after the unit is started by pressing the PLAY button so that the optimum values according to the
disc type (CD/MO) can be obtained by the digital servo.
The adjustment values of the servo such as focus/tracking gain, EF balance, focus bias, etc. stored in the non-volatile memory
(IC802, EEPROM) are sent to the servo circuit when the adjustment mode is started to optimize the servo. (Details of the
adjustment mode are provided in 4. Electrical Adjustments in the Service Manual.)
8. SERVO CIRCUIT
8-1. Outline of Servo Circuit
M
IC802
EEP ROM
SLED
MOTOR
CONTROL
IC601
DSP/
DIGITAL SERVO
IC501
RF AMP
FE/TE
RF/ADIP
IC801
SYSTEM
CONTROLLER
FOCUS
SPINDLE
SLED
TRACKING
IC551(1/2)
SERVO DRIVER
IC551(2/2)
SERVO DRIVER
IC803
FOCUS
COIL
TRACKING
COIL
SPINDLE
MOTOR
SLED
MOTOR
OPTICAL
PICK-UP
ODX-01
M