PIONEER CX 3026 Service Manual

PIONEER CORPORATION 4-1, Meguro 1-Chome, Meguro-ku, Tokyo 153-8654, Japan

PIONEER ELECTRONICS (USA) INC. P.O.Box 1760, Long Beach, CA 90801-1760 U.S.A. PIONEER EUROPE NV Haven 1087 Keetberglaan 1, 9120 Melsele, Belgium PIONEER ELECTRONICS ASIACENTRE PTE.LTD. 253 Alexandra Road, #04-01, Singapore 159936

C PIONEER CORPORATION 2002

K-ZZA. NOV. 2002 Printed in Japan

ORDER NO.

CRT2944

CD MECHANISM MODULE

CX-3026

Model Service Manual CD Mechanism Module DEH-P250/XM/UC CRT2981 CXK5600 DEH-P250/XN/UC DEH-P2500/XM/UC DEH-P2500/XN/UC DEH-P25/XM/UC DEH-P25/XN/UC DEH-P2530R/XM/EW CRT2982 DEH-P2530R/XN/EW DEH-P2500R/XM/EW DEH-P2500R/XN/EW DEH-P2500RB/XM/EW DEH-P2500RB/XN/EW DEH-P2550/XM/ES CRT2983 DEH-P2550/XN/ES DEH-P350/XM/UC CRT2984 DEH-P350/XN/UC DEH-P3500/XM/UC DEH-P3500/XN/UC DEH-P4550/XM/ES DEH-P4550/XN/ES DEH-P4500R/XM/EW CRT2985 DEH-P4500R/XN/EW

- This service manual describes the operation of the CD mechanism module incorporated in models list-

ed in the table below.

- When performing repairs use this manual together with the specific manual for model under repair.

CONTENTS

1. CIRCUIT DESCRIPTIONS ...........................................2

2. MECHANISM DESCRIPTIONS.................................20

3. DISASSEMBLY .........................................................22

234

CX-3026/E

1. CIRCUIT DESCRIPTIONS

Recently, Many CD LSIs have been one-chip LSIs where RF amplifier, DSP, audio DAC, post filter, and other circuits are

integrated.

This product uses this type CD LSI, UPD63712GC, which includes all functions necessary for CD player control.

Basically, this system outputs the analog signal, and the digital output can be supported.

Fig.1.0.1 Block diagram of CD LSI UPD63712GC

A-F

UPD63712GC

EFM

Digital signal processing

RF amplifier

A/D converter

1 bit, Audio DAC

Drive output

Servo PWM output

Digital servo

CD-TEXT

Post filter (SCF)

MPU interface

Microcomputer

Analog output

for system control

CX-3026/E

1.1 PREAMPLIFIER BLOCK (UPD63712GC: IC201)

In the preamplifier block, the pickup output signals are processed to generate signals that are used for the next-stage

blocks: the servo block, demodulator, and control.

After I/V-converted by the preamplifier with built-in photo detectors (inside the pickup), the signals are applied to the

preamplifier block in the CD LSI UPD63712GC (IC201). After added by the RF amplifier in this block, these signals are

used to produce necessary signals such as RF, FE, TE, and TE zero-cross signals.

The CD LSI employs a single power supply system of + 3.3V. Therefore, the REFO (1.65V) is used as the reference volt-

age both for this CD LSI and the pickup. The LSI produces the REFO signal by using the REFOUT via the buffer amplifi-

er and outputs from the pin 90. All the measurements should be made based on this REFO.

Caution: Be careful not to short the REFO and GRD when measuring.

1.1.1 APC (Automatic Power Control)

A laser diode has extremely negative temperature characteristics in optical output at constant-current drive. To keep

the output constant, the LD current is controlled by monitor diodes. This is called the APC circuit. The LD current is

calculated at about 30mA, which is the voltage between LD1 and V+3A divided by 7.5 (ohms).

Fig. 1.1.1 APC

Pickup Unit(P10)

LD-

LD+

14 14

CD CORE UNIT(S10)

100 p

100/16

1R5 x 5

R1 R1

2SB1132

REG 1.25V

APC REG 1.25V

6.5 k

1 k

110 k

1 k

150 k

3 p

Vref

APN

100 k

1SS355

UPD63712GC

LDS

3 p

234

CX-3026/E

1.1.2 RF and RFAGC amplifiers

The photo-detector outputs (A + C) and (B + D) are added, amplified, and equalized inside this LSI, and then provided

as the RF signal from the RFI terminal. The RF signal can be used for eye-pattern check.

The low frequency component of the RFI voltage is:

RFO = (A + B + C + D) x 2

The RFO is used for the FOK generation circuit and RF offset adjustment circuit.

The RFI output from the pin 71 is A/C-coupled outside this LSI, and returned to the pin 76 of this LSI. The signal is

amplified in the RFAGC amplifier to obtain the RFAGC signal. This LSI is equipped with the RFAGC auto-adjustment

function as explained below. This function automatically controls the RFO level to keep at 1.5V by switching the feed-

back gain for the RFAGC amplifier.

The RFO signal is also used for the EFM, DFCT, MIRR, and RFAGC auto-adjustment circuits.

Fig. 1.1.2 RF/AGC/FE

CD CORE UNIT(S10)

Pickup Unit(P10)

VREF

A+C

B+C

VREF

UPD63712GC

10 k

15.2 k

8.8 k

44 k 20 k 11.75 k

RFOFF setup

61 k

140 k

61 k

RFO

AGCI

FEOFF setup

VREF

3.55 k

RF-

RF2-

EQ2

5 k 5 k

To DEFECT/A3T detection

For RFOK generation

EQ1

AGCO

FEO

FE A/D

FE-

2 p

3 p

20 p

1.2 k

47 p

1.2 k

CX-3026/E

1.1.3 Focus error amplifier

The photo-detector outputs (A + C) and (B + D) are applied to the differential amplifier and the error amplifier to obtain

the (A + C - B - D) signal, which is then provided from the pin 93 as the FE signal.

The low frequency component of the FE voltage is:

FE = (A + C - B - D) x 8.8k/10k x 111k/61k x 160k/72k

= (A + C - B - D) x 3.55

The FE output shows 1.5Vp-p S-shaped curve based on the REFO. For the next-stage amplifiers, the cutoff frequency

is 14.6kHz.

1.1.4 RFOK

The RFOK circuit generates the RFOK signal, which indicates focus-close timing and focus-close status during the play

mode, and outputs from the pin 6. This signal is shifted to "H" when the focus is closed and during the play mode.

The DC level of the RFI signal is peak-held in the digital block and compared with a certain threshold level to generate

the RFOK signal. Therefore, even on a non-pit area or a mirror-surface area of a disc, the RFOK becomes "H" and the

focus is closed.

This RFOK signal is also applied to the microcomputer via the low-pass filer as the FOK signal, which is used for pro-

tection and RF amplifier gain switching.

1.1.5 Tracking error amplifier

The photo-detector outputs E and F are applied to the differential amplifier and the error amplifier to obtain the (E - F)

signal, and then provided from the pin 96 as the TE signal.

The low frequency component of the TE voltage is:

TEO = (E - F) x 63k/112k x 160k/160k x 181k/45.4k x 160k/80k

= (E - F) x 4.48

The TE output provides the TE waveform of about 1.16Vp-p based on the REFO. For the next-stage amplifiers, the cut-

off frequency is 21.1kHz.

Fig. 1.1.3 TE

Pickup Unit(P10)

P10

UPD63712GC

112 k

63 k

160 k 160 k

45.4 k

TEOFF setup

161 k

80 k

VREF

TE A/D

160 k

60 k20 k

Inside TEC

TEO

33 p

TE-

TE2

TEC

CD CORE UNIT(S10)

VREF

234

CX-3026/E

1.1.6 Tracking zero-cross amplifier

The tracking zero-cross signal (hereinafter TEC signal) is obtained by amplifying the TE signal 4 times, and used to

detect the tracking-error zero-cross point.

By using the information on this point, the following two operations can be performed:

1. Track counting in the carriage move and track jump modes

2. Sensing the lens-moving direction at the moment of the tracking close (The sensing result is used for the tracking

brake circuit as explained below.)

The frequency range of the TEC signal is between 300Hz and 20kHz.

TEC voltage = TE level x 4

The TEC level can be calculated at 4.64V. This level exceeds the D range of the operation amplifier, and the signal gets

clipped. However, it can be ignored because the CD LSI only uses the signal at the zero-cross point.

1.1.7 EFM

The EFM circuit converts the RF signal into a digital signal expressed in binary digits 0 and 1. The AGCO output from

the pin 76 is A/C-coupled in the peripheral circuit, fed back to the LSI from the pin 71, and sent to the EFM circuit inside

the LSI.

On scratched or dirty discs, part of the RF signal recorded may be missing. On other discs, part of the RF signal

recorded may be asymmetric, which was caused by dispersion in production quality. Such lack of information cannot

be completely eliminated by this AC coupling process. Therefore, by utilizing the fifty-fifty occurrence ratio of binary

digits (0 and 1) in the EFM signal, the EFM comparator reference voltage ASY is controlled, so that the comparator

level always stays around the center of the RFO signal. The reference voltage ASY is made from the EFM comparator

output via the low-pass filter. The EFM signal is put out from the pin 68.

Fig. 1.1.4 EFM

UPD63712GC

RFI

40 k

Vdd

ASY

40 k

EFM signal

40 k

1.5 k 7.5 k

2 k

EFM

CX-3026/E

1.2 SERVO BLOCK (UPD63712GC: IC201)

The servo block controls the servo systems for error signal equalizing, in-focus, track jump and carriage move and so

on. The DSP block is a signal-processing block, where data decoding, error correction, and compensation are per-

formed.

After A/D-converted, the FE and TE signals (generated in the preamplifier block) are applied to the servo block and

used to generate the drive signals for the focus, tracking, and carriage servos.

The EFM signal is decoded in the DSP block, and finally sent out as the audio signal after D/A-converted. In this

decoding process, the spindle servo error signal is generated, supplied to the spindle servo block, and used to gener-

ate the spindle drive signal.

The drive signals for focus, tracking, carriage, and spindle servos (FD, TD, SD, and MD) are provided as PWM3 data,

and then converted to the analog data by the low-pass filter in the driver IC BA5996FP (IC301). These analog drive sig-

nals can be monitored by the FIN, TIN, CIN, and SIN signals respectively. Afterwards, the signals are amplified and

applied to each servo's actuator and motor.

1.2.1 Focus servo system

In the focus servo system, the digital equalizer block works as its main equalizer. The figure 1.2.1 shows the block dia-

gram of the focus servo system.

To close the focus loop circuit, the lens should be moved to within the in-focus range. While moving the lens up and

down by using the focus search triangular signal, the system tries to find the in-focus point. In the meantime, the spin-

dle motor rotation is kept at the prescribed one by using the kick mode.

The servo LSI monitors the FE and RFOK signals and automatically performs the focus close operations at an appropri-

ate timing. The focus loop will close when the following three conditions are satisfied at the same time:

1) The lens moves toward the disc surface.

2) The RFOK signal is shifted to "H".

3) The FE signal is zero-crossed. At last, the FE signal comes to the zero level (or REFO).

When the focus loop is closed, the FSS bit is shifted from "H" to "L". The microcomputer starts monitoring the RFOK

signal obtained through the low-pass filter 10msec after that.

If the RFOK signal is detected as "L", the microcomputer will take several actions including protection.

The timing chart for focus close operations is shown in fig. 1.2.2. (This shows the case where the system fails focus

close.)

In the test mode, the S-shaped curve, search voltage, and actual lens movement can be confirmed by pressing the

focus close button when the focus mode selector displays 01.

Fig. 1.2.1 Block diagram of the focus servo system

UPD63712GC

A+C

B+D

AMP

FOCUS SEARCH

TRIANGULAR

WAVE GENERATOR

A/D

DIG.

CONTROL

PWM

BA5996FP

FOP

FOM

LENS

234

CX-3026/E

Fig. 1.2.2 Timing chart for focus close operations

1.2.2 Tracking servo system

In the tracking servo system, the digital equalizer block is used as its main equalizer. The figure 1.2.3 shows the block

diagram of the tracking servo system.

(a) Track jump

Track jump operation is automatically performed by the auto-sequence function inside the LSI with a command from

the microcomputer. In the search mode, the following five track jump modes are available: 1, 4, 10, 32, and 32*3

In the test mode, 1, 32, and 32*3 track jump modes, and carriage move mode are available and can be switched by

selecting the mode.

For track jumps, first, the microcomputer sets about half the number of tracks to be jumped as the target. (Ex. For 10

track jumps, it should be 5 or so.) Using the TEC signal, the microcomputer counts up tracks. When the counter

reaches the target set by the microcomputer, a brake pulse is sent out to stop the lens. The pulse width is determined

by the microcomputer. Then, the system closes the tracking loop and proceeds to the normal play. At this moment, to

make it easier to close the tracking loop, the brake circuit is kept ON for 50msec after the brake pulse, and the tracking

servo gain is increased.

In the normal operation mode, the FF/REW operation is realized by continuously repeating single jumps about 10

times faster than the normal single jump operation.

(b) Brake circuit

The brake circuit stabilizes the servo-loop close operation even under poor conditions, especially in the setting-up

mode or track jump mode. This circuit detects the lens-moving direction and emits only the drive signal for the oppo-

site direction to slow down the lens. Thus, this makes it easier to close the tracking servo loop. The off-track direction

is detected from the phases of the TEC and MIRR signals.

Output from FD terminal

FE controlling signals

FSS bit of SRVSTS1 resistor

RFOK signals

Search start

A blind period

The broken line in the figure is assumed in the case without focus servo.

You can ignore this for blind periods.

The status of focus close is judged from the statuses of FSS and RFOK after about 10mS.

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