Pioneer PDR-509 Manual de serviço - Página 29

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Também para Pioneer PDR-509: Manual de Instruções (40 páginas), Esquemas de serviço (23 páginas), Manual de serviço (23 páginas), Manual de serviço (14 páginas)

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7. CIRCUIT DESCRIPTIONS

7.1 SERVO CIRCUITS

7.1.1 Control Circuit for the Laser Diode

This circuit controls the optical output of the laser diode. It has two

systems of APC circuit that keep the optical output of the laser diode

constant.

One is the APC circuit for playing power of CD/CD-R/CD-RW and

for erasing power while recording on CD-RW, and the other is for

the recording power while recording on a CD-R or CD-RW.

Each adjustment VR is used for the adjustments shown below.

VR101 (VR101) PB.PW

VR102 (VR163) R REC.PW1

VR103 (VR162) R REC.PW2

VR104 (VR141) RW REC.PW0 : CD-RW bias power adjustment

VR106 (VR164) RW REC.PW1 : CD-RW erasing power adjustment

VR105 (VR161) RW REC.PW2 : CD-RW recording power adjustment

( )In the inside, for PDR-509.

The semi-fixed VRs shown above adjusts the points shown in Fig.

7-1 and 7-2.

Fig. 7-1 CD-R recording waveform

Fig. 7-2 CD-RW recording waveform

PDR-555RW, PDR-V500, PDR-19RW, PDR-509

: Playing power adjustment

: CD-R recording power adjustment

: CD-R overdrive adjustment

CD-R

overdrive

VR103

(VR162)

CD-R

recording

power

VR102

(VR163)

Playing

power

VR101

GND

( )In the inside,

for PDR-509.

CD-RW

recording

power

VR105

(VR161)

CD-RW

erasing

power

VR106

(VR164)

CD-RW

bias power

VR104

(VR141)

GND

( )In the inside,

for PDR-509.

7.1.2 Error Signal Generation Circuit

Employing the 3-beam differential push-pull method, the pickup

has a photodetector that divides the main beam in four and two

detectors that divide the subbeam in two. HF, RF, Wobble, focus

error, and tracking error signals are generated from the voltage signal

output.

7.1.3 Focus Servo

The focus servo employs the same astigmatism method as that of

conventional CD players.

The focus signal generated in the RF processor IC (AK8563, IC103-

pin 11) is input to the decoder IC (CXD2585Q, IC353-pin 39).

The signal processed in the IC is output from pins 29 and 30. This

output signal is input to the driver IC (BA5932FP, IC352), and is

used to drive the focus actuator of the pickup.

7.1.4 Tracking Thread Servo

The tracking servo is also the same as that of conventional CD

players.

The tracking error signal generated in the RF processor IC (AK8563,

IC103-pin 10) is input to the decoder IC (CXD2585Q, IC353-pin

41) and CDR servo amplifier IC (PA9004A, IC247-pin 29).

The signal processed in the decoder IC is output from the pins 31

and 32. This output signal is input to the driver IC (BA5932FP,

IC352), and is used to drive the tracking actuator of the pickup.

The signal input to the CDR servo amplifier IC is input to the

mechanism control (IC204-pin 56) as the P-P value for tracking and

used for detecting the tracking error level.

The tracking error signal also functions as the control signal of the

sled.

7.1.5 Spindle Servo

The spindle servo has four modes: Stop, CAV, EFM-CLV and

Wobble-CLV.

The EFM-CLV used for playing a CD is also used for playing a

recorded CD-R or CD-RW. The A, B, C, and D signals that

correspond to the four divisions of the main beam output from the

pickup are generated in IC102 and IC101 as RF signals.

These RF signals are input to the decoder IC (CXD2585Q, IC353-

pin 43). MDP (pin 25) of a triple-value PWM signal from the sync

signal extracted from RF signal and internal standard signal.

When unrecorded parts of a CD-R or CD-RW are played, the rotation

control signal called Wobble is read out from the guide groove of

the disc. This Wobble signal is output from the RF processor IC

(AK8563, IC103-pin 46), runs through the bandpass filter of the

CDR servo amplifier IC (PA9004A, IC247), and becomes the

Wobble-CLV signal in the ATIP decoder IC (PDJ014A, IC205).

In addition to the Wobble servo, the ATIP decoder IC decodes

information, such as ATIP sync, absolute time, recommended

recording power, lead-in area start time, lead-out start time and disc

application code, from the Wobble signal, and sends the information

to the mechanism-control microcomputer.

If a sudden change in the rotation of the spindle motor is required,

such as upon start, stop, and search, FG is read to detect the rotation

of the spindle motor in the servo mechanism assembly for CAV