PIONEER CX 890 Service Manual

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

PIONEER ELECTRONICS SERVICE INC. P.O.Box 1760, Long Beach, CA 90801-1760 U.S.A.
PIONEER ELECTRONIC [EUROPE] N.V. Haven 1087 Keetberglaan 1, 9120 Melsele, Belgium
PIONEER ELECTRONICS ASIACENTRE PTE.LTD. 253 Alexandra Road, #04-01, Singapore 159936

C PIONEER ELECTRONIC CORPORATION 1999

K-ZZS. FEB. 1999 Printed in Japan

ORDER NO.

CRT2376

CD MECHANISM MODULE

CX-890

CONTENTS

1. MAIN PARTS LOCATIONS........................................2

2. CIRCUIT DESCRIPTIONS ..........................................3

3. MECHANISM OPERATIONS...................................16

4. DISASSEMBLY ........................................................21

NOTE:

- This Service Manual outlines operations of the CD mechanism module used in the models listed blow.

- For repair, use this Service Manual and the Service Manual of the model used in the system.

Model Service manual CD mechanism module CD mechanism unit

CDX-PD6/UC CRT2372 CXK4701 CXB2700

2

CX-890

1. MAIN PARTS LOCATIONS

Frame

Stage front side

Carriage motor (M4)

ELV motor (M2)

Cam gear motor (M1)

Photo interrupter (ELV)

Loading motor (M3)

Servo unit

Disc insertion detectors

Disc insertion detectors

Clamp switch
(S887)

ELV HOME switch
(S886)

Disc ejection detectors

Detection switch
(S885)

STS unit

Spindle
motor (M5)

Insertion completion
switch

Mode switch
(S803)

Door switch
(S802)

Load switch
(S801)

Do not hold the upper frame of the disc insertion slot or
the front side of the stage in the CD mechanism module when
servicing to prevent them from being deformed.

- CD Player Service Precautions

1. For pickup unit(CXX1311) handling, please refer
to"Disassembly"(Page 21).
During replacement, handling precautions shall be
taken to prevent an electrostatic discharge(protection
by a short pin).

2. During disassembly, be sure to turn the power off
since an internal IC might be destroyed when a con­nector is plugged or unplugged.

3

CX-890

2. CIRCUIT DESCRIPTIONS

2.1 Preamplifier (UPC2572GS: IC101)

The preamplifier processes pickup output signals to
generate signals to be sent to the servo, demodulator,
and controller. The preamplifier with built-in photode­tector converts signals from the pickup into intermedi­ate voltage in the pickup. Then, addition is made in the
RF amplifier (IC101) to obtain RF, FE, TE, and TE zero
cross signals. The system consists of the UPC2572GS
and other components explained below. The system
uses a single power source (+5 V). Therefore, the refer­ence voltage of IC101 and the reference voltage of the
power unit and servo circuit are REFOUT (+2.5 V). REFO
UT is obtained from REFOUT of servo LSI (IC201:
UPD63702GF) via a buffer, and is output from Pin 19 of
IC101. This REFOUT is used as reference for all mea­surements.
Note:Do NOT short-circuit REFOUT and GND during
measurement.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

20

X12

RF

envelope

AGC

Detection

X3

Phase detection

3T detection

Bottom

DC shift

Peak

Control

DC shift

Bottom

Peak

120kΩ

DEFECT circuit

FE

BAL

FE
BAL

Vcc

Mirror circuit

FE

BAL

APC

X2

Vcc

FE-BAL

TE-BAL

ASY

EFM-OUT

C.DEF

DEFECT

RFOK

MIRR

3T-OUT

C.FE

FE-OUT

FE-

GND

TE-

TE-OUT1

TE-OUT2

DET-IN

DET-OUT

VREF-INVREF-OUT

LDON

LD

PD

E

F

D

B

C

A

Vcc

C2.3T

C1.3T

RF-

RF-OUT

RF-IN

C AGC

AGC-OUT

EFM-IN

HPF

TE
BAL

EFM comparator

Control

Fig. 1 Block Diagram of UPC2572GS

1) Automatic Power Control (APC) circuit

Laser diode has negative temperature characteristics
with great optical output when the diode is driven with
constant current. Therefore, current must be controlled
by a monitor diode to ensure constant output. Thus
functions the APC circuit. LD current can be obtained by
measuring the voltage between LD1 and GND. The cur­rent value is approximately 35 mA.

Vcc (5V)

Vr

LD MD

UPC2572GS

16

PD

17

LD

15

Q101
2SD1664

C124

0.1µF

C101
(100µF/6.3V)

R101
10Ω

LD1

R102
12Ω

5V

CONT

Q102 UMD2N

18

5V

5V

1kΩ

150kΩ

16kΩ

R112

2.2kΩ

C104

0.33µF

5

1kΩ

2.5V

Pickup unit

Fig. 2 APC Circuit

Voltage between LD1 and GND(mv)

LD current(mA) =

10 Ω + 12 Ω

4

CX-890

2) RF amplifier and RF AGC amplifier

Photodetector outputs (A+C) and (B+D) are added,
amplified and equalized in IC101, and output to the RFI
terminal as RF signal. (Eye pattern can be checked at
this terminal.)
Low-frequency components of voltage RFI is:

RFI = ((A + C) + (B + D)) x 3.22
where R111 is offset resistor to keep RFI signal within
the output range of the preamplifier. RFI signal is goes
under AC coupling, and is input to Pin 4 (RFIN termi­nal).
IC101 contains an RF AGC circuit. RFO output from Pin
2 is maintained to a constant level (1.2 ±0.2 Vp-p). The
RFO signal is used in the EFM, DFCT, and MIRR circuits.

3) EFM circuit

The EFM circuit converts RF signal into digital signals of
"0" and "1". RFO signal after AC coupling is input to Pin
1, and supplied to the EFM circuit.
Asymmetry caused during manufacturing of discs can­not be eliminated solely by AC coupling. Therefore, the
system controls the reference voltage ASY of the EFM
comparator by using the fact that probability to gener­ate "0" and "1" is 50% in EFM signal. This reference volt­age ASY is generated by output from the EFM com­parator through L.P.F. EFM signal is output from Pin 35.
As signal level, amplification is 2.5 Vp-p around
REFOUT.

4) DFCT (defect) circuit

DFCT signal detects mirror defect in discs, and is output
from Pin 33. The system outputs "H" when a mirror
defect is detected.

If disc is soiled, the system determines it as lack of mir­ror. Therefore, the system inputs the DFCT signal out­put to the HOLD terminal of servo LSI. Focus and track­ing servo drives change to Hold status only when DFCT
output is in "H" so that performance of the system upon
detection of defect can be improved.

5) RFOK circuit

The RFOK circuit outputs signal to show the timing of
focus closing servo, as well as the status of focus clos­ing during playback. The signal is output from Pin 32.
The system inputs the RFOK signal output to the RFOK
terminal of servo LSI. The servo LSI issues Focus Close
command. The system outputs signal in "H" during
focus closing and playback.

CN101

13

6

DETECT

13

11

10

10kΩ

20kΩ

9.3kΩ

RFI

+5V

R111
27kΩ

Vcc

×12

ASY

12

20kΩ

(RF AGC)

AGC

RF

ENVELOPE

HPF

VDC

RFOK

20kΩ

33

36

35

34

PEAK

DEFECT

EFM

UPC2572GS

A+C

10kΩ

B+D

9.3kΩ

20kΩ

10kΩ
10kΩ

R105

6.8kΩ

C125 5pF

C105
24pF

R125
0R0

R104

8.2kΩ

RFIN

C107

4.7µF/35V

C122

0.1µF

C106

RFO

REFOUT (+2.5V)

DEFECT

BOTTOM

R107 8.2kΩ

R106 18kΩ

C111 3300pF

C110

C112 0.047µF

6 54 3 21

32

0.1µF

2200pF

HOLD

Fig. 3 RF AMP, RF AGC, EFM, DFCT, RFOK Circuit

5

CX-890

6) Focus-error amplifier

The system outputs photodetector output (A+C) and
(B+D) as FE signal (A+C)-(B+D) from Pin 28 via the dif­ference amplifier, then via the error amplifier.
Low-frequency components of voltage FEY is:

An S curve equivalent to approximately 1.6 Vp-p is
obtained at FE output (Pin 28) by using REFO as refer­ence. The cut-off frequency of the amplifier of the last
layer is 12.4 kHz.

7) Tracking-error amplifier

Outputs E and F from the photodetector are output as
TE signal (E-F) from Pin 24 via the difference amplifier,
then via the error amplifier.
Low-frequency components of voltage TEY is:

TE waveforms equivalent to approximately 1.5 Vp-p are
obtained at TE output (Pin 24) by using REFO as refer­ence. The cut-off frequency of the amplifier of the last
layer is 19.5 kHz.

8) Tracking zero-cross amplifier

Tracking zero-cross signal (TEC signal) is generated by
amplifying TE waveforms (voltage at Pin 24) by a factor
of four. The signal is used for detecting the zero-cross
point of tracking error in the servo LSI UPD63702AGF.
The purposes of detecting the zero-cross point are as
follows:
(1)To be used for counting tracks for carriage move and

track jump.

(2)To be used for detecting the direction of lens move-

ment when tracking is closed. (To be used in the
tracking brake circuit mentioned later.)
The frequency range of TEC signal is from 500 Hz to

19.5 kHz.
Voltage TEC = TE level x 4

In other words, the TEC signal level is calculated as 6
Vp-p. This level exceeds the D range of the operation
amplifier, resulting in the signal to clip. However,
there shall be no problem, since the servo LSI uses
only zero-cross point.

65

9.3kΩ

9.3kΩ

20kΩ

10kΩ
10kΩ

6

13

13

12

10kΩ
10kΩ

20kΩ

FE VCA

38

REFOUT

C114
390pF

FE

R108
33kΩ

28

27

17.2kΩ

50pF

gm=1/68.8kΩ

90kΩ

10

11

CN101

A+C

B+D

F.BAL

REFOUT (+2.5V)

gm CONDUCTANCE

UPC2572GS

Fig. 4 Focus-error amplifier

Fig. 5 Tracking-error amplifier,

Tracking zero-cross amplifier

CN101

R117
16kΩ

R116
16kΩ

14

15

9

11

31kΩ

31kΩ

50pF
63kΩ

C123

4.7nF

R114
10kΩ

R113
10kΩ

TBAL

C115
120pF

R109
68kΩ

R115
1kΩ

C126
15nF

TE

4R

R

F

E

23

TEC

C116

6.8nF

TE VCA
gm=1/17kΩ

63kΩ

37

24

5pF

TOFST

R110
130kΩ

50pF

25

REFOUT (+2.5V)

gm CONDUCTANCE

UPC2572GS

63kΩ 68kΩ

TEY=(E-F) X X

(31kΩ+16kΩ) 17kΩ

: (TE level of pickup unit x 5.36)

20kΩ 90kΩ R108

FEY=(A+C)-(B+D)X X X

10kΩ 68.8kΩ 17.2kΩ

: (FE level of pickup unit x 5.02)

6

CX-890

9) MIRR (mirror) circuit

MIRR signal shows ON and OFF track information. The
signal is output from Pin 31.
The status of MIRR signal is as follows:

Laser beam ON track: MIRR = "L"
Laser beam OFF track: MIRR = "H"

The signal is used in the brake circuit mentioned later.

10) 3T OUT circuit

The system detects flickering of RF signal when distur­bance is input to the focus servo loop, and outputs the
difference of phase between FE signal and RF-level
fluctuation signal from Pin 30. The resulting signal is
obtained through L.P.F. with a fc of 40 Hz. This signal is
used for automatic adjustment of FE bias.

MIRR

COMP

DC

shift

PeakAGC

Bottom

RFO

Detection

A

1.5V

UPC2572GS

(Peak) – (Bottom)

4

31

RFIN

B

Z

C

RFO

PEAK HOLD

BOTTOM HOLD

MIRROR

1

A

0

False MIRR caused by dirt

True MIRR

OFF TRACK

Dirt, etc.

B

C

Z

Ø

3T-OUT

FE signal

RFIN

UPC2572GS

C113
10nF

FEY

3T detection

C117

0.033µF

120kΩ

L.P.F

Phase detection

8

+

H.P.F

10kΩ

10kΩ

1kΩ

C2.3T

C109

100pF

C1.3T

C108

0.027µF

8

7

30

29

4

AGC

Differential
rectification

3T LEVEL ENVELOPE
DETECTOR

Phase

comparison

Fig.6 MIRR Circuit

Fig. 7 MIRR Circuit

Fig. 8 3T OUT Circuit

7

CX-890

2.2 Servo (UPD63702AGF: IC201)

The servo consists of mainly two parts. The first part is
the servo processing unit to equalize error signals and
control track jump, carriage move, in focus, etc. The
second part is the signal processing unit to perform
data decoding, error correction, and interpolation.
The system converts FE and TE signals from analog to
digital in IC201, then outputs drive signals of the focus,
tracking, and carriage systems via the servo block. The
EFM signal input from the preamplifier is decoded by
the signal processing unit, and eventually output as
audio signal after conversion into analog from digital
signals via the DA converter (IC201 contains audio
DAC). Then, the system generates error signal for the
spindle servo in the decoding process, sends the signal
to the spindle servo to generate drive signal for spin­dle.
After that, drive signals for focus, tracking, carriage,
and spindle are amplified in IC301 and BA5986FM, and
supplied to respective actuators and motors.

1) Focus servo system

The main equalizer of focus servo is located in the
UPD63702AGF. Fig. 9 shows block diagram of the focus
servo.
For the focus servo system, the lens must be posi­tioned within the focusing range in order to perform
focus closing. To achieve this, the system moves the
lens upward/downward by focus-search voltage of tri­angular waveform to detect the focusing point. During
searching, the system kicks the SPDL motor to main­tain rotation speed to set speed.
The servo LSI monitors FE and RFOK signals so that
focus closing is performed automatically at an appro­priate point.
Focus closing is performed when the following four
conditions are satisfied:
(1)When the lens moves nearer to the disc.
(2)RFOK = "H"
(3)FZD signal (in IC) is latched to "H"
(4)FE = 0 (REFOUT as reference)

FOCUS
ERROR

D/A

FD

FIN

DRIVER

FOP

FOM

IC301

BA5986FM

LENS

IC 201 UPD63702AGF

76

64

2

4

3

14

13

FOCUS SEARCH

TRIANGULAR WAVE

GENERATOR

DAC

DIGITAL

EQUALIZER

CONTROL

A/D

R301
10kΩ

R302
15kΩ

Fig. 9 Focus servo block diagram

8

CX-890

When the conditions mentioned above are satisfied and
focus is closed, the XSO terminal changes from "H" to
"L". Then, the microcomputer starts monitoring RFOK
signal through L.P.F after 40 ms.
If the system judges RFOK signal as "L", the microcom­puter takes actions, including protection.
Fig. 10 shows operations related to focus closing. (The
illustration shows when the system cannot perform
focus closing.) S curve, search voltage, and actual lens
behavior can be checked by pressing the Focus Close
button when "01" is shown in Focus Mode Select in Test
mode.

REFOUT

FD

LENS POSITION
RELATIVE TO DISC

NEAR

FAR

"JUST FOCUSED"

SIN

REFOUT

Expanding around "Just Focused Point"

REFOUT

RFI

FOK

FEX

FZD
THRESHOLD
LEVEL

FZD
(INTERNAL SIGNAL)

Focus closing would normally take place at these points

XSO
(IN THE EVENT
FOCUS IS
CLOSED)

LEVEL

Fig. 10 Sequence of Focus Closing