Sony HCDXB-20 Service manual

Tuner section

FM stereo, FM/AM superheterodyne tuner

FM tuner section

Tuning range 87.5 – 108.0 MHz
Antenna FM lead antenna
Antenna terminals 75 Ω unbalanced
Intermediate frequency 10.7 MHz

AM tuner section

Tuning range
(2 band model)

North American model:

530 – 1,710 kHz
(with the tuning interval set at 10 kHz)

Other models: 531 – 1,602 kHz

(with the tuning interval set at 9 kHz)
530 – 1,710 kHz
(with the tuning interval set at 10 kHz)

(3 band model)

MW: 531 – 1,602 kHz

(with the tuning interval set at 9 kHz)

LW: 153 – 279 kHz

(with the tuning interval set at 3 kHz)
Antenna AM loop antenna
Antenna terminals External antenna terminal
Intermediate frequency 450 kHz

General

Power requirements

North American model:

120 V AC, 60 Hz

Mexican model: 120 V AC, 50/60 Hz
European model: 230 V AC, 50/60 Hz
Australian, South African and Thailand models:

220 – 240 V AC, 50/60 Hz

Other models: 110 – 120 V AC or 220 – 240 V AC,

50/60 Hz (adjustable with voltage selector)
Power consumption 130 W
Dimensions (w/h/d) incl. projecting parts and controls

Approx.355 × 423 × 440 mm

(14 × 16 3/4 × 17 3/8 in)
Mass Approx. 14.0 kg (30 lb 14 oz.)
Supplied accessories AM loop antenna (1)

Remote RM-SG5 (1)

FM lead antenna (1)

SERVICING NOTE

NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK
OR BASE UNIT

The laser diode in the optical pick-up block may suffer electrostatic
break-down because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.

NOTES ON LASER DIODE EMISSION CHECK

The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pick­up block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.

Design and specifications are subject to change without notice.

CAUTION

Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous
radiation exposure.

Notes on chip component replacement

• Never reuse a disconnected chip component.

• Notice that the minus side of a tantalum capacitor may be

damaged by heat.

Flexible Circuit Board Repairing

• Keep the temperature of soldering iron around 270˚C

during repairing.

• Do not touch the soldering iron on the same conductor of the

circuit board (within 3 times).

• Be careful not to apply force on the conductor when soldering

or unsoldering.

SAFETY-RELATED COMPONENT WARNING!!

COMPONENTS IDENTIFIED BY MARK ! OR DOTTED LINE WITH
MARK ! ON THE SCHEMATIC DIAGRAMS AND IN THE PARTS
LIST ARE CRITICAL TO SAFE OPERATION. REPLACE THESE
COMPONENTS WITH SONY PARTS WHOSE PART NUMBERS
APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS
PUBLISHED BY SONY.

Laser component in this product is capable of emitting radiation
exceeding the limit for Class 1.

This appliance is classified as
a CLASS 1 LASER product.
The CLASS 1 LASER
PRODUCT MARKING is
located on the rear exterior.

This caution
label is located
inside the unit.

— 2 —

SAFETY CHECK-OUT

After correcting the original service problem, perform the following
safety checks before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC leakage. Check leakage as
described below.

LEAKAGE

The AC leakage from any exposed metal part to earth Ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microampers).
Leakage current can be measured by any one of three methods.

1. A commercial leakage tester, such as the Simpson 229 or RCA
WT -540A. F ollow the manufactur ers’ instructions to use these
instruments.

2. A battery-operated AC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.

3. Measuring the voltage drop across a resistor by means of a
VOM or battery-operated A C voltmeter . The “limit” indication
is 0.75 V, so analog meters must have an accurate low-v oltage
scale. The Simpson 250 and Sanwa SH-63Trd are e xamples of
a passive VOM that is suitable. Nearly all battery operated
digital multimeters that have a 2V AC range are suitable. (See
Fig. A)

T o Exposed Metal

Parts on Set

AC

0.15

µ

F

Fig. A. Using an A C v oltmeter to check A C leakage.

1.5 k

Ω

Earth Ground

Voltmeter
(0.75 V)

TABLE OF CONTENTS

1. GENERAL ········································································· 4

—FRONT PANEL— ·························································4
—BACK PANEL—····························································5

2. DISASSEMBLY

2-1. Top Cover ··········································································· 6
2-2. Front Panel Assy································································· 6
2-3. Main Board········································································· 7
2-4. Main Section······································································· 7
2-5. CD Mechanism Deck Section ············································ 8
2-6. Tape Mechanism Deck ······················································· 8
2-7. Cassette Door ····································································· 9
2-8. CD Door Assy ···································································· 9
2-9. Base Unit ··········································································10
2-10. Disc T able········································································· 10

3. MECHANICAL ADJUSTMENTS ····························· 11

4. ELECTRICAL ADJUSTMENTS ······························· 11

5. DIAGRAMS

5-1. Circuit Boards Location ··················································· 16
5-2. Block Diagram —Deck Section— ··································· 17
5-3. Block Diagram —Tuner/CD Section— ··························· 19
5-4. Schematic Diagram —Main Section (1/2)— ··················· 21
5-5. Schematic Diagram —Main Section (2/2)—

(US, AUS, MX model) ····················································· 25

5-6. Printed Wiring Board —Main Section—

(US, AUS, MX model) ····················································· 29

5-7. Printed Wiring Board —Main Section—

(AEP, UK, E, SP, MY, AR model)···································· 34

5-8. Schematic Diagram —Main Section (2/2)—

(AEP, UK, E, SP, MY, AR model)···································· 39
5-9. Schematic Diagram —Display Section— ························ 43
5-10. Printed Wiring Board —Display Section— ····················· 47
5-11. Printed Wiring Board —CD Section—···························· 52
5-12. Schematic Diagram —CD Section— ······························· 57
5-13. Schematic Diagram —Power Section— ·························· 60
5-14. Printed Wiring Board —Power Section— ······················· 63
5-15. IC Block Diagrams ··························································· 68
5-16. IC Pin Function Description············································· 71

— 3 —

6. EXPLODED VIEWS

6-1. Top Cover Section ···························································· 73
6-2. CD Door Section ······························································ 74
6-3. Panel Section ····································································75
6-4. Main Section····································································· 76
6-5. Cassette Button Section···················································· 77
6-6. Cassette Mechanism Deck Section··································· 78
6-7. CD Mechanism Deck Section ·········································· 79
6-8. Base Unit Section ····························································· 80

7. ELECTRICAL PARTS LIST ······································ 81

– FRONT PANEL –

SECTION 1

GENERAL

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1 I/u (POWER) button
2 DISPLA Y/DEMO button
3 SPECTRUM ANALYZER button
4 ENTER/NEXT button
5 TUNER MEMORY button
6 TUNING MODE button
7 TUNER/BAND button
8 TUNING – button
9 TUNING + button
0 STEREO/MONO button
!¡ TAPE button
!™ CD button
!£ PHONO button
!¢ DBFB button
!∞ VOLUME knob
!§ DOLBY NR button
!¶ SURROUND button
!• · button
!ª 0 button
@º ) button

@¡ 6p button
@™ P button
@£ 6 button
@¢ · button
@∞ DISC SKIP button
@§ P button
@¶ p button
@• ) button
@ª ≠ AMS ± button
#º 0 button
#¡ DISC1 button
#™ DISC2 button
#£ DISC3 button
#¢ DISC4 button
#∞ DISC5 button
#§ r button
#¶ · button
#• 0 button
#ª ) button
$º 6p button

$¡ P button
$™ PHONES jack
$£ ROCK button
$¢ POP button
$∞ JAZZ button
$§ SALSA button
$¶ FLAT button
$• SLEEP button
$ª t/CLOCK SET button
%º DAILY1 button
%¡ PLAY MODE button
%™ REPEAT button
%£ EDIT button
%¢ 1/ALL DISC button

— 4 —

– BACK PANEL –

1

2

1 ANTENNA terminal
2 PHONO jack
3 SPEAKER terminal

3

— 5 —

SECTION 2

DISASSEMBLY

Note : Follow the disassembly procedure in the numerical order given.

2-1. TOP COVER

1

Three screws

3

Top cover

2

Seven screws

1

Three screws

2-2. FRONT PANEL ASSY

3

Front panel assy

1

Screw

2

Four screws

— 6 —

2-3. MAIN BOARD

1

Two screws

2

Three screws

2

Three screws

2

Two screws

1

Three screws

3

Rear panel

7

MAIN board

6

Two screws

5

Two flat wires

4

Connector

2-4. MAIN SECTION

1

Two screws

2

Main section

1

Two screws

— 7 —

2-5. CD MECHANISM DECK SECTION

3

Five screws

(BVTP 3 × 8)

4

CD mechanism

deck section

2

Flat wire and

lead wire

2-6. TAPE MECHANISM DECK

1

Open the clamp.

1

Six screws

2

Tape mechanism deck

— 8 —

2-7. CASSETTE DOOR

3

Door spring

2

Cassette door (L)

2-8. CD DOOR ASSY

1

Cassette door (R)

7

Connector

5

3

Door spring

DOOR SW board

6

Four screws

8

CD door assy

4

Screw

— 9 —

3

Three flat wires

1

Three screws

2

PLAY SW board

2-9. BASE UNIT

t

3

Base unit

1

Yoke bracke

2-10. DISC TABLE

Note:

When the disc table is installed, adjust the positions
of roller cam and mark z as shown in the figure,
then set to the groove of disc table.

A

2

1

Screw

(BVTP 3 × 8)

2

Bracket (BU)

Boss

1

Screw

(BVTP 3 × 8)

3

Step screw

4

Disc table

— 10 —

A

SECTION 3

MECHANICAL ADJUSTMENTS

SECTION 4

ELECTRICAL ADJUSTMENTS

Precaution

1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback head pinch rollers
erase head rubber belts
capstan idlers

2. Demagnetize the record/playback head with a head
demagnetizer.

3. Do not use a magnetized screwdriver for the adjustments.

4. After the adjustments, apply suitable locking compound to the
parts adjusted.

5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.

Torque Measurement

Torque

FWD
FWD

back tension

FF/REW

Torque meter

CQ-102C

CQ-102C

CQ-201B

Meter reading

40 to 70 g • cm

(0.56 - 0.97 oz • inch)

1 to 5 g • cm

(0.01 - 0.07 oz • inch)

55 to 140 g • cm

(0.76 - 1.94 oz • inch)

DECK SECTION 0 dB=0.775V

1. Demagnetize the record/playback head with a head
damagnetizer.

2. Do not use a magnetized screwdriver for the adjustments.

3. After the adjustments, apply suitable locking compound to the
parts adjusted.

4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.

5. The adjustments should be performed in the order given in this
service manual. (As a general rule, playback circuit adjustment
should be completed before performing recording circuit
adjustment.)

6. The adjustments should be performed for both L-CH and R­CH.

Tape

P-4-A100

WS-48B

Record/Playback Head Azimuth Adjustment
(Deck A, Deck B)

Note: Perform this adjustments for both decks.

Procedure:

1. Mode : Playback

test tape
P-4-A100
(10kHz, –10dB)

Signal

10 kHz, –10 dB

3 kHz, 0 dB

SPEAKER
terminal (JK703)

Used for

Azimuth Adjustment

Tape Speed Adjustment

level meter

set

+
–

— 11 —

2. Turn the adjustment scre w and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 2 dB of peak.

L-CH
peak

screw
position

R-CH
peak

output
level

within
2dB

L-CH
peak

R-CH
peak

within 2dB

screw
position

4. After the adjustments, apply suitable locking compound to the
parts adjusted.

Adjustment Location:

Remove the cassette lid before adjustment (See page 9)

Adjustment screws
REC/PB head (deck A)
or PB head (deck B)

3. Mode: Playback

test tape
P-4-A100
(10kHz, –10dB)

in phase 45˚ 90˚ 135˚ 180˚

SPEAKER
terminal (JK703)
(L-CH)

L

set

R

SPEAKER
terminal (JK703)
(R-CH)

Waveform of oscilloscope

good

wrong

Tape Speed Adjustment (Deck A)

Procedure:

1. Mode: Playback

test tape
WS-48B
(3kHz, 0dB)

set

SPEAKER
terminal (JK703)

frequency counter

+
–

2. Adjust the SFR809 so that the frequency counter reads 3,000
Hz ± 90Hz.

Adjustment Location: MAIN board (See page 14)

Sample Value of Wow and flutter

W. RMS (JIS) within 0.3%
(test tape: WS-48B)

— 12 —

TUNER SECTION 0 dB=1µV

AM Tuning Voltage Adjustment

Main board

TP1

F
G
VT

DC voltmeter

+
–

Procedure:

1. Set the reception frequency of the unit to 530 kHz.

2. Adjust L105 for 1.2 ± 0.05 V reading on the DC voltmeter.

3. Set the reception frequency of the unit to 1,710 kHz.

4. Confirm that the voltage reading on the DC voltmeter is within

8.0 ± 0.5 V.

Adjustment Location: MAIN board (See page 14)

AM Tracking Adjustment

loop antenna

AM RF SSG

loop antenna
(Supplied accessories)

set

30% amplitude
modulation by
400 Hz signal

60 cm

Field strength dB (

µ

V/m) =SSG output level dB (µV/m) –26 dB.

Procedure:

1. Tune the set to 600 kHz.

2. Set the output of AM RF SSG so that the input le vel of the set
will become 60 dB (µV/m).

3. Adjust L104 so that when the waveform on the oscilloscope is
maximum, no noise appears.

4. Tune the set to 1,400 kHz.

FM Tuning Voltage Adjustment (US, Australian, Mexican model)

Main board

TP1
IF
G
VT

DC voltmeter

+
–

Procedure :

1. Set the reception frequency of the unit to 87.5 MHz.

2. Adjust L103 for 1.2 ± 0.05V reading on the DC voltmeter.

3. Set the reception frequency of the unit to 108 MHz.

4. Confirm that the voltage reading on the DC voltmeter is within

7.8 ± 0.5V.

AM ANTENNA
terminal (TM1)

5. Adjust TC102 so that when the waveform on the oscilloscope
is maximum, no noise appears.

• Repeat the procedures in each adjustment several times, and the

tracking adjustment should be finally done by the trimmer
capacitors.

Adjustment Location: MAIN board (See page 14)

Adjustment Location: MAIN board (See page 14)

— 13 —

FM Tracking Adjustment

)

(US, Australian, Mexican model)

Procedure:

FM RF SSG

set

SPEAKER terminal (JK703)

FM ANTENNA terminal (JK101)

Carrier frequency : 90 MHz, 106 MHz
Modulation : AUDIO 1kHz, 75kHz deviation (100%)
Output level : 20 dB (at 75 Ω open)

oscilloscope

1. Tune the set to 90 MHz.

2. Adjust L102 so that when the waveform on the oscilloscope is
maximum, no noise appears.

3. Tune the set to 106 MHz.

4. Adjust TC101 so that when the waveform on the oscilloscope
is maximum, no noise appears.

• Repeat the procedures in each adjustment several times, and the

tracking adjustment should be finally done by the trimmer
capacitors.

Adjustment Location: MAIN board

FM Tuned Level Adjustment

FM RF SSG

Ω

coaxial

75

set

Carrier frequency : 98 MHz
Modulation : AUDIO 1 kHz, 75 kHz

Output level : 28 dB (at 75

deviation (100%)

Ω

open)

FM ANTENNA terminal
(JK101)

Procedure:

1. Supply a 28 dB 98 MHz signal from the ANTENN A terminal.

2. Tune the set to 98 MHz.

3. Adjust SFR101 to the point (moment) when the TUNED
indicator will change from going off to going on.

Adjustment Location: MAIN board

Adjustment Location

[MAIN BOARD] — Component side —

SFR101
(FM Tuned Level)

IC103

SFR809
(Tape speed)

L105
(AM Tuning
Voltage)

L103
(FM Tuning
Voltage)

IC301

JK101

TC102

L104

L102

TC101

(AM
Tracking)

(FM
Tracking

— 14 —

CD SECTION

)

Note:

1. CD Block is basically constructed to operate without
adjustment. Therefore, check each item in order given.

2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.

3. Use an oscilloscope with more than 10MΩ impedance.

4. Clean the object lens by an applicator with neutral detergent
when the signal level is low than specified value with the
following checks.

5. Adjust the focus bias adjustment when optical block is replaced.

Focus Bias Adjustment

CD DECODER
board

TP02

FEO

VC

Procedure:

1. Connect DC voltmeter to test point TP02 on CD DECODER
board.

2. Turned Power switch on.

3. Put disc (YEDS-18) in and stop.

4. Adjust VR01 so that the DC voltmeter reading is 0 ± 20 mV.

DC voltmeter

+
–

RF Level Check

CD DECODER
board

TP01

RF
VC

oscilloscope

Procedure :

1. Connect oscilloscope to test point TP01 on CD DECODER
board.

2. Turned Power switch on.

3. Put disc (YEDS-18) in and playback.

4. Confirm that oscilloscope waveform is clear and check RF
signal level is correct or not.

Note: Clear RF signal waveform means that the shape “◊” can be

clearly distinguished at the center of the waveform.

VOLT/DIV: 200 mV
TIME/DIV: 500 nS

level: 1.0 Vp-p

+0.3
–0.2

Adjustment Location: CD DECODER board

Adjustment Location: CD DECODER board

Focus Gain Adjustment (VR02)

This gain has a margin, so even if it is slightly off.
There is no problem.
Therefore, do not perform this adjustment.
Please note that it should be fixed to mechanical center position
when you moved and do not know original position.

Adjustment Location

[CD DECODER BOARD] — Component side —

TP01

VR01
(Focus Bias)

IC01

VR02
(Focus Gain

TP02

— 15 —

5-1. CIRCUIT BOARDS LOCATION

MAIN board

SECTION 5

DIAGRAMS

AMP board

POWER SELECT board

LED board

DISC board

DOOR SW board

POWER SUPPLY
board

FRONT board

VR board

PLAY SW board

JOG board

R/P SWITCH board

TABLE SENSOR board

MOTOR board

CONNECTOR board

— 16 —

DISC NO LED board

MOTOR (6P)(C) board

CD DECODER board

5-2. BLOCK DIAGRAM — DECK SECTION —

PHONO

TAPE B

TAPE A

HRP901
REC/PB

SECTION

SECTION

MECHANISM

BLOCK

SW201

S804

S804

S803

S802

S801

16

HP901

PB

HEAD

HEAD

HE901

ERASE

HEAD

A

TUNER

B

CD

M

JK301

L

R

TU MUTE

TABLE SENSOR

TU L

ST IND

CD L

SCOR
SENS
SQSO

XLAT
SQCK
DATA

COUNT

FOK

CLK

STB

DO

CE

DI

UP SW

R CH

R CHR CH

Q803,805

R CH

PLAY/REC
CONTROL

Q823

PLAY/REC
CONTROL

D803

SFR809

TAPE

SPEED

DRIVE

SFR807

SFR807

Q801

D802

REC +B

REC +B

A MOTOR +B

B PLAY +B

MOTOR +12V

IC402

PLAY/REC
CONTROL

SFR801

BIAS OSC

+12V

L805
BIAS

TRAP

L809

Q818

Q809

78

77

UP SW

TABLE SENSOR

6
5

9

7

Q816,817

BIAS

SWITCH

MUTE
CONT

91

STB

BIAS
OSC

CE

93CE97

EQ AMP

IC801

PB OUT

A/B

CLK

98

CLK

16

12

X601

6MHz

2

SFR803

3

DO

76

28

SO

FOK

COUNT

X217X1

Q803

10

MPX

14

Q807

REC

MUTE

MUTE

13

D805

D804

D801 D806

Q825,826

MUTE
CONT

B PLAY +B A MOTOR +B

Q819

95

97

34

96

75

27

XLAT

DATA

SQCK

SQSO

A

SENS

SCOR

81

VR601

VOLUME

VR UP

REC AMP

MUTE

15 1

89

3

SI

VR DOWN

82

B

PB/REC

AMP
IC802

D807

73

TU MUTE

FM ST IND

11

12

10

74

CD SYNC

FUNCTION TAPE

CD ENCODER A83CD ENCODER B

84

A

B

VR602

CD

ENCODER

BUFFER

CLK

98

ALATCH

Q811

Q813
MUTE

DI

SFR805

2
3

4

SW101

10k

9k

14

16

D808

LED DRIVE

IC602

+5.6V

HCD-G2500/XB20/XB22

SELECTOR

IC301

11

Q602

Q602

9

10

12

CONTROL

RESET

SWITCH

12

DI

RESET

CLK14DI15CE

CLK

16

CE

Q301

DOLBY

AMP

IC803

IC803

11

9

12

5

Q815

PB

MUTE

MUTE

D810

D809

Q820

Q822

LED601-609

16

SPANA

IC603

1

8

26

25

24

SPANA 3

SPANA 2

SPANA 1

Q605,606

SW

SYSTEM CONTROLLER/

MODE

68

S641

DOOR

514

FLD DRIVER

IC601

23

IC302

K 0

89

6

K1 K4

22 19

KEY

MATRIX

S601-624

S601-624
S626-640

LT COM
4

Q307

SURROUND

CONTROL

Q310

7

3 2

SURROUND

8

FLAT

ROCK

8

Q303

5

6

DBFB HIGH

DBFB NORMAL

Q311
MUTE

Q603
MUTE

SWITCH

Q601

Q601

POWER

DOWN DET

2

13

SYSTEM MUTE

1

POWER DOWN

Q604
MUTE

RM601

Q305
HIGH

Q308

NORMAL

3

REMOTE
CONTROL
RECEIVER

2

29

REMOTE

LINE AMP

4
3

D302

D602

IC303

Q402

POWER

MUTE

45

.

D303

47 50

2

Q410
MUTE

DRIVE

P1 P21

+30V

-30V

-12V

-27V

+12V

CD +7.5V

+12V

M +12V

.

52 67

FLD601

FLD DISPLAY

HP AMP

IC401

3

Q407
MUTE

Q709

MUTE

1

G1 G15

30 44

POWER AMP

IC701

3 11

Q401

-12V
REG

Q702
+7.5V

REG

Q409
+5.6V

REG

Q403

FILTER

Q405,406

SITCHING

1

POWER

Q703

-27V
REG

Q701
+12V

REG

Q712

P MUTE

CONT

D719

D714

Q706

Q708

Q711

AC OFF

DET

D701

RECT

D731,732
VOLTAGE

DOUBLER

D705-708

RECT

R CH

Q404

IC702

SP
RELAY
DRIVE

4

AC3.4V
AC3.4V

SP

DET

6

PT301

• RCH is omitted

• Signal Path

RL701

F702

F703

E, SP, MY, AR MODEL

: PB (DECK A)

: PB (DECK B)

: REC (DECK A)

: FM

: CD

+12V

1

2

SW401

JK401

PHONES

JK703

SPEAKER

AC

IN

: PHONO

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