Sony HCD-GX255 User manual

SERVICE MANUAL
COMPACT DISC DECK RECEIVER
HCD-GX255/RG170/RG470
Ver. 1.2 2005.09
9-879-612-03
2005I05-1
© 2005.09
Sony Corporation
Personal Audio Group
Published by Sony Engineering Corporation
– Continued on next page –
Canadian Model
HCD-GX255
AEP Model
E Model
HCD-RG170/RG470
Australian Model
HCD-RG170
Photo: HCD-GX255
•HCD-GX255 is the amplifier, CD player, tape
deck and tuner section in MHC-GX255.
•HCD-RG170 is the amplifier, CD player, tape
deck and tuner section in MHC-RG170.
•HCD-RG470 is the amplifier, CD player, tape
deck and tuner section in MHC-RG470.
SPECIFICATIONS
Model Name Using Similar Mechanism NEW
CDM74KFS-F1BD81C (Except Mexican model) or
CD Mechanism Type CDM74KFS-K6BD83S (Canadian, AEP, East European, Russian, E2, E51 models)/
CD CDM74KFS-F1BD84 (Mexican model)
Section BU-F1BD81C (Except Mexican model) or
Base Unit Name BU-K6BD83S-WOD (Canadian, AEP, East European, Russian, E2, E51 models)/
BU-F1BD84 (Mexican model)
Optical Pick-up Block Name KSM-215DCP or KSM-213DCP
TAPE Model Name Using Similar Mechanism HCD-GX355/RG270
Section Tape Transport Mechanism Type CWM43FF13
Amplifier section
Canadian model:
HCD-GX255
Continuous RMS power output (reference):
65 + 65 watts (6 ohms at
1kHz,10% THD)
Total harmonic distortion less than 0.07% (6 ohms at
1kHz,40 W)
European and Russian models:
HCD-RG470
DIN power output (rated): 110 + 110 watts (6 ohms at
1kHz,DIN)
Continuous RMS power output (reference):
140 + 140 watts (6 ohms at
1kHz,10% THD)
Music power output (reference):
280 + 280 watts (6 ohms at
1kHz,10% THD)
HCD-RG170
DIN power output (rated): 20 + 20 watts (6 ohms at
1kHz,DIN)
Continuous RMS power output (reference):
25 + 25 watts (6 ohms at
1kHz,10% THD)
Music power output (reference):
50 + 50 watts (6 ohms at
1kHz,10% THD)
Other models:
HCD-RG470
The following measured at AC 120, 127, 220, 240 V
50/60 Hz
DIN power output (rated): 130 + 130 watts (6 ohms at
1kHz,DIN)
Continuous RMS power output (reference):
160 + 160 watts (6 ohms at
1kHz,10% THD)
HCD-RG170
The following measured at AC 120, 127, 220, 240 V
50/60 Hz
DIN power output (rated): 50 + 50 watts (6 ohms at
1kHz, DIN)
Continuous RMS power output (reference):
65 + 65 watts (6 ohms at
1kHz, 10% THD)
Inputs
AUDIO IN (stereo mini jack):
voltage 250 mV,
impedance 47 kilohms
MIC (phone jack) (Latin American model only):
sensitivity 1 mV,
impedance 10 kilohms
Outputs
PHONES (stereo mini jack):
accepts headphones of
8ohmsormore
VIDEO OUT (phono jack) (Mexican model only):
max. output level 1Vp-p,
unbalanced, Sync
negative, load impedance
75 ohms
SPEAKER: accepts impedance of 6 to
16 ohms
•Abbreviation
E2 : 120V AC area in E model
E51 : Chilean and Peruvian models

2
HCD-GX255/RG170/RG470
Tape deck section
Recording system 4-track 2-channel, stereo
Frequency response 50 −13,000 Hz (±3 dB),
using Sony TYPE I
cassettes
Tuner section
FM stereo, FM/AM superheterodyne tuner
FM tuner section
Tuning range
North American model: 87.5 −108.0 MHz
(100 kHz step)
Other models: 87.5 −108.0 MHz
(50 kHz step)
Antenna FM lead antenna
Antenna terminals 75 ohms unbalanced
Intermediate frequency 10.7 MHz
AM tuner section
Tuning range
Pan-American models: 530 −1,710 kHz
(with the tuning interval
set at 10 kHz)
531 −1,710 kHz
(with the tuning interval
set at 9 kHz)
European, Russian and Saudi Arabian models:
531 −1,602 kHz (with the
tuning interval set at
9kHz)
Other models: 530 −1,710 kHz
(with the tuning interval
set at 10 kHz)
531 −1,602 kHz
(with the tuning interval
set at 9 kHz)
Antenna AM loop antenna
Intermediate frequency 450 kHz
General
Power requirements
North American model: 120 V AC, 60 Hz
European and Russian models:
230 V AC, 50/60 Hz
Australian model: 230 −240V AC, 50/60 Hz
Argentine model: 220 V AC, 50/60 Hz
Mexican model: 127 V AC, 60 Hz
Saudi Arabian model: 120 −127, 220 or
230 −240V AC, 50/60 Hz
Adjustable with voltage
selector
Other models: 120 V, 220 V or
230 −240V AC, 50/60 Hz
Adjustable with voltage
selector
Power consumption
Canadian model:
HCD-GX255: 110 watts
European and Russian models:
HCD-RG470: 240 watts
0.25 watts (at the Power
Saving Mode)
HCD-RG170: 70 watts
0.25 watts (at the Power
Saving Mode)
Other models:
HCD-RG470: 170 watts
HCD-RG170: 125 watts
Dimensions (w/h/d) (excl. speakers)
Approx. 280 ×325 ×
430 mm
Mass (excl. speakers)
Canadian model:
HCD-GX255: Approx. 8.5 kg
European and Russian models:
HCD-RG470: Approx. 10.0 kg
HCD-RG170: Approx. 7.2 kg
Other models:
HCD-RG470: Approx. 10.4 kg
HCD-RG170: Approx. 8.5 kg
Design and specifications are subject to change
without notice.
CD player section
System Compact disc and digital
audio system
Laser Diode Properties Emission duration:
continuous
Laser Output*:
Less than 44.6µW
*Thisoutputisthe value measurement at a distance of
200mm from the objective lens surface on the
Optical Pick-up Block with 7mm aperture.
Frequency response 2 Hz −20 kHz (±0.5 dB)
Signal-to-noise ratio More than 90 dB
Dynamic range More than 90 dB

3
HCD-GX255/RG170/RG470
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 the 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.
This appliance is classified as
a CLASS 1 LASER product.
This marking is located on the
rear exterior.
CAUTION
Use of controls or adjustments or performance of procedures
otherthan thosespecifiedhereinmayresult inhazardousradiation
exposure.
UNLEADED SOLDER
Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
•Unleaded solder melts at a temperature about 40 ˚C higher
than ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350 ˚C.
Caution: The printed pattern (copper foil) may peel away if
the heated tip is applied for too long, so be careful!
•Strong viscosity
Unleaded solder is more viscou-s (sticky, less prone to flow)
than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.
•Usable with ordinary solder
It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED LINE
WITH MARK 0ON 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.
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFIÉS PAR UNE MARQUE 0SUR
LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES
PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ DE
FONCTIONNEMENT. NE REMPLACER CES COM- POSANTS
QUE PAR DES PIÈCES SONY DONT LES NUMÉROS SONT
DONNÉS DANS CE MANUEL OU DANS LES SUPPLÉMENTS
PUBLIÉS PAR SONY.

4
HCD-GX255/RG170/RG470
TABLE OF CONTENTS
1. SERVICING NOTES ............................................... 5
2. GENERAL ................................................................... 6
3. DISASSEMBLY
3-1. Disassembly Flow ........................................................... 8
3-2. Case (Top) ....................................................................... 9
3-3. Door (CD)........................................................................ 9
3-4. Front Panel Section ......................................................... 10
3-5 Mechanical Deck (CWM43FF13) ................................... 10
3-6. CD Mechanism Deck (CDM74KFS-F1BD81C
(Except MX model)/CDM74KFS-F1BD84
(MX model)).................................................................... 11
3-7. Back Panel Section .......................................................... 11
3-8. MAIN Board.................................................................... 12
3-9. BD Board/CD Board ....................................................... 12
3-10. DRIVER Board, SW Board............................................. 13
3-11. Optical Pick-up Block (KSM-215DCP) .......................... 13
3-12. SENSOR Board ............................................................... 14
3-13. MOTOR (TB) Board ....................................................... 14
3-14. MOTOR (LD) Board ....................................................... 15
4. TEST MODE.............................................................. 16
5. ELECTRICAL ADJUSTMENT ............................ 20
6. DIAGRAMS
6-1. Block Diagram – CD SERVO Section – ........................ 21
6-2. Block Diagram – AUDIO/VIDEO Section – ................. 22
6-3. Block Diagram – AMP Section – ................................... 23
6-4. Block Diagram
– PANEL, POWER SUPPLY Section – .......................... 24
6-5. Printed Wiring Board
– CD Board – (Except MX model) ................................. 26
6-6. Schematic Diagram
– CD Board – (Except MX model) ................................. 27
6-7. Printed Wiring Board – BD Board – (MX model) ......... 28
6-8. Schematic Diagram – BD Board – (MX model) ............ 29
6-9. Printed Wiring Boards – CHANGER Section –............. 30
6-10. Schemtic Diagram – CHANGER Setion –..................... 31
6-11. Printed Wiring Board – MAIN Board – (Suffix-11) ...... 32
6-12. Schematic Diagram – MAIN Board (1/3) –
(Suffix-11) ....................................................................... 33
6-13. Schematic Diagram – MAIN Board (2/3) –
(Suffix-11) ....................................................................... 34
6-14. Schematic Diagram – MAIN Board (3/3) –
(Suffix-11) ....................................................................... 35
6-15. Printed Wiring Board – MAIN Board – (Suffix-12) ...... 36
6-16. Schematic Diagram – MAIN Board (1/3) –
(Suffix-12) ....................................................................... 37
6-17. Schematic Diagram – MAIN Board (2/3) –
(Suffix-12) ....................................................................... 38
6-18. Schematic Diagram – MAIN Board (3/3) –
(Suffix-12) ....................................................................... 39
6-19. Printed Wiring Board – POWER Board –
(GX255/RG170) .............................................................. 40
6-20. Schematic Diagram –POWER Board –
(GX255/RG170) .............................................................. 41
6-21. Printed Wiring Board – POWER Board –
(RG470: AEP, EE, RU) ................................................... 42
6-22. Schematic Diagram – POWER Board –
(RG470: AEP, EE, RU) ................................................... 43
6-23. Printed Wiring Board – POWER Board –
(RG470: E2, E51, AR, MX) ............................................ 44
6-24. Schematic Diagram – POWER Board –
(RG470: E2, E51, AR, MX) ............................................ 45
6-25. Printed Wiring Boards
– AUDIO, MIC, HEADPHONE Boards – ...................... 46
6-26. Schematic Diagram
– AUDIO, MIC, HEADPHONE Boards – ...................... 47
6-27. Printed Wiring Boards – CD-G Section –
(MX model only)............................................................. 48
6-28. Schematic Diagram – CD-G Section –
(MX model only)............................................................. 49
6-29. Printed Wiring Board – PANEL Section (1/2) ............... 50
6-30. Printed Wiring Board – PANEL Section (2/2) ............... 51
6-31. Schematic Diagram – PANEL Section (1/2) .................. 52
6-32. Schematic Diagram – PANEL Section (2/2) .................. 53
6-33. Printed Wiring Boards – TRANS Section –
(GX255/RG170) .............................................................. 54
6-34. Schematic Diagram – TRANS Section –
(GX255/RG170) .............................................................. 55
6-35. Printed Wiring Boards – TRANS Section –
(RG470: AEP, EE, RU) ................................................... 56
6-36. Schematic Diagram – TRANS Section –
(RG470: AEP, EE, RU) ................................................... 57
6-37. Printed Wiring Boards – TRANS Section –
(RG470: E2, E51, AR, MX) ............................................ 58
6-38. Schematic Diagram – TRANS Section –
(RG470: E2, E51, AR, MX) ............................................ 59
7. EXPLODED VIEWS
7-1. Overall Section ................................................................ 77
7-2. Back Panel Section .......................................................... 78
7-3. Front Panel Section ......................................................... 79
7-4. Key Section ..................................................................... 80
7-5. Chassis Section................................................................ 81
7-6. Transformer Section ........................................................ 82
7-7. CD Mechanism Deck Section-1
(CDM74KFS-F1BD81C (Except MX model)/
CDM74KFS-F1BD84 (MX model)) ............................... 83
7-8. CD Mechanism Deck Section-2
(CDM74KFS-F1BD81C (Except MX model)/
CDM74KFS-F1BD84 (MX model)) ............................... 84
8. ELECTRICAL PARTS LIST................................ 85
•Abbreviation
AR : Argentina model
E2 : 120V ACArea in E model
E51: Chilean and Peruvian model
EE : East European model
MX: Mexican model
RU : Russian model

5
HCD-GX255/RG170/RG470
SECTION 1
SERVICING NOTES
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 pick-
up block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
Carry outthe “Scurvecheck” in“CD sectionadjustment” andcheck
that the S curve waveforms is output three times.
•MODEL IDENTIFICATION
– Back Panel –
Label indication Model
2-560-990-01 GX255
2-560-991-01 RG170: AEP, EE, RU
2-560-993-01 RG470: E2, E3
2-560-994-01 RG170: EA
2-560-996-01 RG170: AUS
2-560-997-01 RG170: E51
2-560-998-01 RG170: AR
2-580-000-01 RG470: AEP, EE, RU
2-580-001-01 RG470: E2
2-580-002-01 RG470: E51
2-580-003-01 RG470: MX
2-580-004-01 RG470: AR
•Abbreviation
AR : Argentina model
AUS:Australian model
CND : Canadian model
E2 : 120V ACArea in E model
E3 : 240V ACArea in E model
E51 : Chilean and Peruvian models
EA : Saudi Arabia model
EE : East European model
MX : Mexican model
RU : Russian model
Model number labe
l
DISCRIMINATION OF THE MAIN BOARD
There are two types of suffix-11 and suffix-12 of the MAIN boards
used in set as follows.
– MAIN BOARD (Component Side) –
Part Number
AEP, EE, RU models : 1-865-919-12 only
Other models : 1-865-919-11 or 1-865-919-1
2

6
HCD-GX255/RG170/RG470 SECTION 2
GENERAL This section is extracted from
instruction manual.
•Location of Controls
Main unit
ALBUM +/−qs
AUDIO IN wl
AUDIO IN jack wf
CD es
CD SYNC wj
Deck A wg
Deck B qk
DISC 1 −3 qa
DISC SKIP/EX-CHANGE qd
Disc tray 0
DISPLAY 3
Display window 5
ECHO LEVEL1) wa
EFFECT ON/OFF 4
ENTER 4
EQ BAND qs
GROOVE 4
ILLUMINATION 2
MIC jack2) wd
MIC LEVEL2) ws
MULTIPLEX1) 6
Operation Dial
(−EQ +/l L/
−TUNING +) qj
P FILE 4
PHONES jack w;
PLAY MODE 8
Power illuminator qg
PRESET EQ 4
REC PAUSE/START wl
Remote sensor 7
SURROUND 4
TAP E A/B e;
TUNER/BAND ea
TUNING MODE 8
VOLUME control ql
?/1 (power) 1
X(pause) qs
x(stop) qs
M(fast forward) qs
N(play) qs
m(rewind) qs
Z(eject) qf
PUSH Z(deck B) (eject) qh
ZPUSH (deck A) (eject) wh
1) Mexican model only
2) Latin American model only
(Mexican model comes with
2microphone jacks)
ALPHABETICAL ORDER
A – O P – Z
BUTTON DESCRIPTIO
j
s
S
H
l
L
AB
wd
12345678 q
;
qf
qa
qs
qd
w;
ql
wa
ws
qg
qh
qk
wf
wg
wj
wh
wk
ea
e;
es
wl
qj
NS

7
HCD-GX255/RG170/RG470
Remote control
ALBUM + qa
ALBUM −qd
CD qk
CLEAR qg
CLOCK/TIMER SELECT 2
CLOCK/TIMER SET 3
DISC SKIP q;
DISPLAY wa
ENTER 9
EQ qf
FM MODE 4
FUNCTION 6
PLAY MODE w;
REPEAT 4
SLEEP ws
TAPE qj
TUNER BAND 5
TUNER MEMORY ql
TUNING MODE w;
VOLUME +/−qs
?/1 (power) 1
m/M (rewind/fast forward)
7
N(play) 8
X(pause) 8
x(stop) 8
+/−(tuning) qh
./> (go back/go forward)
qh
ALPHABETICAL ORDER
A – E F – Z
BUTTON DESCRIPT
IONS
4
5
6
7
8
9
q;
ws 1
qd
qg
qf
wa
w;
ql
qk
qj
qh
qa
qs
3
2

8
HCD-GX255/RG170/RG470
•This set can be disassembled in the order shown below.
3-1. DISASSEMBLY FLOW
SECTION 3
DISASSEMBLY
SET
3-2. CASE (TOP)
(Page 9)
3-3. DOOR (CD)
(Page 9)
3-8. MAIN BOARD
(Page 12) 3-13. MOTOR (TB) BOARD (Page 14)
3-14. MOTOR (LD) BOARD
(Page 15)
3-10. DRIVER BOARD,
SW BOARD
(Page 13)
3-4. FRONT PANEL SECTION
(Page 10)
3-5. MECHANICAL DECK
(CWM43FF13)
(Page 10)
3-6. CD MECHANISM DECK
(CDM74KFS-F1BD81C
(EXCEPT MX MODEL)/
CDM74KFS-F1BD84
(MX MODEL))
(Page 11)
3-9. BD BOARD/
CD BOARD
(Page 12)
3-11. OPTICAL PICK-UP BLOCK
(KSM-215DCP)
(Page 13)
3-12. SENSOR BOARD
(Page 14)
3-7. BACK PANEL SECTION
(Page 11)

9
HCD-GX255/RG170/RG470
Note: Follow the disassembly procedure in the numerical order given.
3-2. CASE (TOP)
1 three screws
(case 3 TP2)
2 two screws (B3)
7 two screws (B3)
3 case (side-R)
4 three screws
(case 3 TP2)
6 case (side-R)
5 two screws (B3)
0 case (top)
8
8
9
9
2 Pull-out the disc tray.
3 two claws
4 door (CD)
1 Turn the pulley in the direction of the arrow.
Front panel side
CD mechanism deck
–BOTTOM VIEW–
3-3. DOOR (CD)

10
HCD-GX255/RG170/RG470
3-4. FRONT PANEL SECTION
(E2, E51, AR, MX)
1 connector
(CN061)
5 connector
(CN066)
8 screw (B3)
7 screw
(B3)
6 four screws (B3)
9 front panel section
4 connector (CN065)
• Abbreviation
AR : Argentina model
E2 : 120V AC Area in E model
E51 : Chilean and Peruvian models
MX : Mexican model
3 connector (CN201)
2 connector
(CN203)
(MX)
4 two screws
(+BVTP 2.6
× 8)
6 screw
(+BVTP 2.6 × 8) (except MX
)
(+BVTP 2.6 × 10) (MX)
5 two screws
(+BVTP 2.6 × 8) (except MX)
(+BVTP 2.6
× 10) (MX)
8 mechanical deck
(CWM43FF13)
7 cover (TCM)
1 screw
(+BVTP 2.6
× 8) (except MX)
(+BVTP 2.6
× 10) (MX)
2 harness
3 coating clip
(except MX)
• Abbreviation
MX : Mexican model
3-5. MECHANICAL DECK (CWM43FF13)

11
HCD-GX255/RG170/RG470
(MX)
(MX)
1 three screws (B3)
3 wire (flat type) (13 core) (CN701)
6 connector
(CN1004)
7 CD mechanism deck
(CDM74KFS-F1BD81C (except MX)/CDM74KFS-F1BD84 (MX))
4 wire (flat type) (27 core) (CN201) (Except MX)
wire (flat type) (31 core) (CN201) (MX)
5 wire (flat type)
(13 core) (CN331)
2
• Abbreviation
MX : Mexican model
1 connector
(CN906)
2 connector
(CN903)
3 connector
(CN901)
5 connector
(CN041)
6 two screws (B3)
7 two screws (B3)
8 back panel section
4 wire (flat type) (15 core)
(CN381)
3-6. CD MECHANISM DECK
(CDM74KFS-F1BD81C (EXCEPT MX MODEL)/CDM74KFS-F1BD84 (MX MODEL))
3-7. BACK PANEL SECTION

12
HCD-GX255/RG170/RG470
3-8. MAIN BOARD
3-9. BD BOARD/CD BOARD
1 connector
(CN907)
2 connector
(CN905)
3 two screws (B3)
5 MAIN board
4 connector
(CN441)
MAIN board
5 BD board (MX)/
CD board (except MX)
2 screw
(+BVTP 2.6)
4 Remove soldering from the four points.
1 wire (flat type) (16 core) (CN101
)
3 gap tube
• Abbreviation
MX : Mexican model

13
HCD-GX255/RG170/RG470
3-11. OPTICAL PICK-UP BLOCK (KSM-215DCP)
3-10. DRIVER BOARD, SW BOARD
3 connector
4p (CN703)
4 DRIVER board
6 SW board
2 wire (flat type) 5p (CN702)
1 two screws
(+BTTP (M2.6))
5 screw
(+BTTP (M2.6))
4 two coil springs
(insulator)
7 two coil springs
(insulator)
5 two insulators
8 two insulators
0 s crew (+BVTP 2.6 × 8 )
qa gap tube
6 two floating screws
(+PTPWH M2.6)
2 h older (213) ASSY
qs Remove the four solders of motor.
qd wire (flat type)
(CN101)
qf B D board (MX)/
C D board (except MX)
qg optical pick-up block
(KSM-215DCP)
1 floating screw
(+PTPWH M2.6)
3 two floating screws
(+PTPWH M2.6)
9
• Abbreviation
MX : Mexican model

14
HCD-GX255/RG170/RG470
2 t ray
3 b elt (table)
5 p ulley (table)
8 s crew
(+BTTP (M2.6))
0 SENSOR board
7 g ear (geneva)
9 connector
(
CN731)
1 floating screw
(+PTPWH M2.6)
6 floating screw
(+PTPWH M2.6)
4 floating screw
(+PTPWH M2.6)
6 Remove the two solderings of motor.
8 MOTOR (TB) board
7 t able motor assy (M741)
5 two screws
(+BTTP (M2.6))
4
3
wire (flat type) 5 core (CN742)
1 stopper
2 stopper
3-12. SENSOR BOARD
3-13. MOTOR (TB) BOARD

15
HCD-GX255/RG170/RG470
4 Remove the two solderings of motor.
3 MOTOR (LD) board
1 b elt (loading)
5 l oading motor assy (M751)
2 two screws
(+BTTP (M2.6))
3-14. MOTOR (LD) BOARD

16
HCD-GX255/RG170/RG470 SECTION 4
TEST MODE
MC COLD RESET
The cold reset clears all data including preset data stored in the
RAM to initial conditions. Execute this mode when returning the
set to the customer.
Procedure:
1. Press three buttons of x, [ILLUMINATION] and [DISC 1]
simultane-ously.
2. The message “COLD RESET” is displayed on the fluorescent
indicator tube momentarily, then becomes standby states.
AM TUNING INTERVAL CHANGE-OVER
(Except AEP, East European, Russian model)
A step of AM tuning interval can be changed over between 9 kHz
and 10 kHz.
Procedure:
1. Press the I/1button to turn the power on.
2. Press the [TUNER/BAND] button to select “AM”.
3. Press the I/1button to turn the power off.
4. Press two buttons of [PLAY MODE/TUNING MODE] and I/1
simultaneously.
5. Themessage “AM 9KSTEP” or“AM10K STEP”is displayed
on the fluorescent indicator tube, and thus the channel step is
changed over.
CD SHIP (LOCK) MODE
This mode moves the optical pick-up to the position durable to
vibration. Use this mode when returning the set to the customer
after repair.
Procedure:
1. Press the I/1button to turn the power on.
2. Press the [CD] button to select “CD”.
3. Press two buttons of [CD] and [POWER] simultaneously.
4. Themessage “LOCK”is displayedon thefluorescent indicator
tube, and the CD ship mode is set.
CD SHIP (LOCK) MODE & COLD RESET
This mode is used to perform CD chip (lock) mode and cold reset
simultaneously.
Procedure:
1. Press the I/1button to turn the power on.
2. Press the [CD] button to select “CD”.
3. Pressthree buttonsof x,[CD] and [DISPLAY] simultaneously.
4. The message “COLD RESET” is displayed on the fluorescent
indicator tube momentarily, then becomes standby states.
CD TRAY LOCK MODE
This mode is used to unable to take sample disc out of tray in the
shop.
Procedure:
1. Press the I/1button to turn the power on.
2. Press the [CD] button to select “CD”.
3. Load a disc and press two buttons of xand Zfor 5 seconds.
4. The message “LOCKED” is displayed on the fluorescent
indicator tube and the CD tray is locked. (Even if pressing
the Zbutton, the message “LOCKED” is displayed on the
fluorescent indicator tube and the CD tray is locked)
5. To release this mode, press two buttons of xand Zfor 5
seconds.
6. The message “UNLOCKED” is displayed on the fluorescent
indicator tube and the CD tray is unlocked.
AMP TEST MODE
This mode is used to display the parameter of amplifier IC and
display the VACS status.
Procedure:
1. Press the I/1button to turn the power on.
2. Press three buttons of x, [ILLUMINATION] and [PRESET EQ]
simultaneously.
3. When the AMP test mode is activated, the message “AMP
TEST IN” is displayed on the fluorescent indicator tube
momentarily, then amplifier adjustment mode is displayed on
the fluorescent indicator tube.
4. Press the [DISPLAY] button to changed over between VACS
status display mode and the amplifier IC parameter display
mode.
5. In this mode, press the [GROOVE] button to changed over
DBFB on/off, and “DBFB ON” or “DBFB OFF” is displayed
on the fluorescent indicator tube.
6. In this mode, press the [SURROUND] button to changed over
surround on/off, and “SURROUND ON” or “SURROUND
OFF” is displayed on the fluorescent indicator tube.
7. In this mode, press the [EQ BAND] button to enter the equalizer
adjustment mode.
In the equalizer adjustment mode, press the [EQ BAND] button
to change over the adjustment band as LOW/MID/HIGH.And
turn the
[ --- EQ + ]Ll
knob to adjust the equalizer level of
each bands.
8. To release theamplifierIC parameterdisplay modeorequalizer
adjustment mode, press the I/1button to the power off.

17
HCD-GX255/RG170/RG470
AGING MODE
This mode can be used for operation check of CD section and tape
deck section.
CD section and tape deck section work in parallel.
If an error occurred:
Theaging operationstops onlyanerror occurredsections anddisplay
then status.
If no error occurs:
The aging operation continues repeatedly.
Procedure:
1. Press the I/1button to turn the power on.
2. Press the [CD] button to select “CD”.
3. Load three discs and insert two tape to the deckA and B.
4. Pressthree buttonsof x,[ILLUMINATION] and [DISC SKIP/EX-
CHANGE] simultaneously.
5. Aging operations of CD and tape are started at the same time.
6. To release this mode, press the I/1button to turn the power
off or press the function buttons to change the function.
1. Display at the Aging Mode
Display operating state of CD section and tape deck section
alternately.
If an error occurred, stop display which that section.
2. CD Section
The sequence during the aging mode is following as below.
Display at the aging mode is the same as the normal operation.
Aging mode sequence (CD section) :
Start (from disc 1)
Disc chucking
TOC read
Play first track for 2 seconds
Play last track for 2 seconds
EX-change open/close
Open the disc tray
Disc skip
Close the tray
Change the next disc.
3. Tape Deck Section
The sequence during the aging mode is following as below.
If an error occurred, stop display that step.
Aging mode sequence (tape deck section) :
Rewind the tape A and B
“TAPE AAG-1 or TAPE BAG-2”
Shut off
FWD play the tape A
“TAPE AAG-3”
2 minutes
Rewind the tape A
“TAPE AAG-6”
Shut off
FWD play the tape B
“TAPE BAG-3”
2 minutes
Rewind the tape B
“TAPE BAG-6”
Shut off
Note: “TAPE *AG-*” is display of each step.
PANEL TEST MODE
This mode is used to check the fluorescent indicator tube, LEDs
and buttons.
Procedure:
1. Press the I/1button to turn the power on.
2. Press three buttons of x, [ILLUMINATION] and [GROOVE]
simultaneously.
3. Fluorescent indicator tube and LEDs are all turned on.
4. Presstwo buttons of [ALBUM ---] and [ENTER] simultaneously,
mode is changed over.
5. In the key check mode, press each key, the defined key number
of every each key list is displayed on the fluorescent indicator
tube.
6. In the key count check mode, “KEYCNT 0” is displayed on
the fluorescent indicator tube. Each time a key is pressed, “K”
value increases. However, once a key is pressed, it is no longer
taken into account.
7. In the headphone input check mode, connect the headphone,
the message “H_P ON” is displayed on the fluorescent
indicator tube, and disconnect the headphone, the message
“H_P OFF” is displayed on the fluorescent indicator tube.
8. In the volume check mode, “VOLUME FLAT” is displayed
on the fluorescent indicator tube. Turn the [MASTER
VOLUME] knob clockwise, the message “VOLUME UP”
is displayed on the fluorescent indicator tube momentarily
and turn the [MASTER VOLUME] knob counterclockwise,
the message “VOLUME DOWN” is displayed on the
fluorescent indicator tube momentarily.

18
HCD-GX255/RG170/RG470
MC TEST MODE
This mode is used to check operations of microprocessor.
Procedure:
1. Press the I/1button to turn the power on.
2. Press three buttons of x, [ILLUMINATION] and [DISC 3]
simultane-ously.
3. When the MC test mode is activated,VACS level is displayed
on the fluorescent indicator tube momentarily.
4. Turn the
[ --- EQ + ]Ll
knob clockwise, the message
“ALL EQ MAX” is displayed on the fluorescent indicator
tube momentarily and turn the
[ --- EQ + ]Ll
knob
counter-clockwise, the message “ALL EQ MIN” is
displayed on the fluorescent indicator tube momentarily.
5. Press the [PRESET EQ] button, the message “ALL EQ FLAT”
is displayed on the fluorescent indicator tube momentarily.
6. Turn the [MASTER VOLUME] knob clockwise, the message
“VOLUME MAX” is displayed on the fluorescent indicator
tube momentarily and turn the [MASTER VOLUME] knob
counterclockwise,the message“VOLUMEMIN” isdisplayed
on the fluorescent indicator tube momentarily.
7. Press the [GROOVE] button to changed over VACS on/off.
8. When the [CD SYNC] key is pressed with the test tape (AMS-
100,AMS-110A) in the deck, number of space between tunes
is counted, then ifAMS-110A is set, “OK” is displayed on the
fluorescent indicator tube and if AMS-100 is set, “NG” is
displayed on the fluorescent indicator tube.
9. Press the I/1button to release from this mode, then cold reset
is performed.
VERSION DISPLAY MODE
This mode is used to check the model, destination and software
version.
Procedure:
1. Press the I/1button to turn the power on.
2. Press three buttons of x, [ILLUMINATION] and [DISC 2]
simultane-ously.
3. Whenthis modeis activated, modelanddestination isdisplayed
on the fluorescent indicator tube.
4. Press the [DISPLAY] button to changed over between software
version and year, month, day of the software creation display
mode and model and destination display mode.
5. To release this mode, press three buttons of x, [ILLUMI
NATION] and [DISC 2] simultaneously.
CD ERROR CODE DISPLAY MODE
This mode can be used for error code display of CD section.
Procedure:
1. Press the I/1button to turn the power on.
2. Press the [CD] key to select “CD”.
3. Press three buttons of x, [CD] and [DISC 1] simultaneously.
4. When this mode is activated, mechanism deck error code is
displayed on the fluorescent indicator tube.
5. Press the [GROOVE] button to changed over between optical
pick-up error code display mode and mechanism deck error
code mode.
6. Turn the
[ --- EQ + ]Ll
knob to change over display of error
history.
7. To release this mode, press the I/1button to turn the power
off.
1. Mechanism Deck Error Code Mode
When this mode is entered, mechanism deck error code is displayed
with the 10-character format on the fluorescent indicator tube.
The first digit from the left indicates:
The first digit from the left indicates which mode the error history
is. In the mechanism deck error code mode, “M” is displayed on
the fluorescent indicator tube.
The second digit from the left indicates:
(Error history number display)
The second digit from the left indicates which order the error history
is. “1” indicates the latest error history, and each time the number
increases by one, the error history goes back to one-previous error.
The third and 4th digit from the left indicates:
(Error status display)
The third and 4th digit from the left indicates which error status is
indicated.
Display Status
00 No error
08 Table operation time-out (Table does not move to the target
position within the specified time)
16 In the chucking down operation, the operation was retried
by the maximum number of times but the operation could
not be completed
17 In the chucking up and down operation, the reverse
recovery processing was attempted but it could not be
recovered
18 In the chucking up operation, the operation was retried by
the maximum number of times but the operation could not
be completed
20 Loading operation time-out (Table does not move to the
target position within the specified time)
22 As the chuck was in the ex-open status at the initialization,
the closing was attempted but could not be completed
The 5th and 6th digit from the left indicates:
(Present status display)
The 5th and 6th digit from the left indicates which operating status
when an error occurred is indicated.
Display Status
01 Open completion status
02 From open status, the movement to chucking down position
is under way
03 From chucking down position, the open operation is under
way
04 Chucking down completion status
10 The chucking down operation is under way
11 The chucking up operation is under way
12 Close completion status
13 From close status, the ex-open operation is under way
14 From ex-open status, the close operation is under way
18 Ex-pen completion status

19
HCD-GX255/RG170/RG470
The 5th and 6th digit from the left indicates:
(Error step display)
The 5th and 6th digit from the left indicates which processing when
a trouble occurred
Display Contents
01 Power OFF in progress
02 Initialize in progress
03 Oscillation stopping
04 From oscillation stop, oscillation starting
05 Stopping
06 Stop operation is under way
07 Start operation in progress
08 TOC read in progress
09 Search operation is under way
0A Playback operation is under way
0B Pause operation is under way
0C Playback manual search operation is under way
0D Pause manual search operation is under way
0E —
The 7th and 8th digit from the left indicates:
The 7th and 8th digit from the left indicates which operation in
progress when a trouble occurred. (Step of each processing of the
5th and 6th digits is indicated)
5 REPEAT LIMIT CANCEL MODE
Number of repeat for CD playback is 5 times when the repeat mode
is “REPEAT”. This mode is used to enables CD to repeat playback
for limitless times.
Procedure:
1. Press the I/1button to turn the power on.
2. Press the [CD] button to select “CD”.
3. Press three buttons of x, [CD] and [PLAY MODE/TUNING
MODE] simultaneously.
4. The message “LIMIT OFF” is displayed on the fluorescent
indicator tube momentarily, CD repeat 5 limit is cancelled.
The 7th and 8th digit from the left indicates:
(Motor status display)
The 7th and 8th digit from the left indicates which motor output
status when an error occurred is indicated.
Display Status
×0No table motor output
×1Table motor forward output
×2Table motor backward output
×3Table motor break output
0×No loading motor output
1×Loading motor forward output
2×Loading motor backward output
3×Loading motor break output
The 9th and 10 th digit from the left indicates:
(Tray status display)
The9th and10th digitfrom theleft indicateswhich targetprocessing
when an error occurred is indicated.
Display Status
01 Open operation
12 Close operation
18 Ex-open operation
2. Optical Pick-up Error Code Mode
When this mode is entered, optical pick-up error code is displayed
with the 8-character format on the fluorescent indicator tube.
The first digit from the left indicates:
The first digit from the left indicates which mode the error history
is. In the optical pick-up error code mode, “D” is displayed on the
fluorescent indicator tube.
The second digit from the left indicates:
(Error history No. display)
The second digit from the left indicates which order the error history
is. “1” indicates the latest error history, and each time the number
increases by one, the error history goes back to one-previous error.
The third and 4th digit from the left indicates:
(Error status display)
The third and 4th digit from the left indicates which error status is
indicated.
Display Status
01 Not focused (TOC read without a disc)
02 GFS NG (TOC read with a disc chucked)
03 Start operation time-over
04 Defocused continuously (Defocused during TOC reading)
05 Q code not entered for specified time
06 Tracking not turned ON
07 Blank disc (Blank disc TOC read)

20
HCD-GX255/RG170/RG470 SECTION 5
ELECTRICAL ADJUSTMENTS
CD SECTION
Note:
1. CD Block is basically designed to operate without adjustment.
Therefore, check each item in order given.
2. UseYEDS-18 (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10MΩimpedance.
4. Clean the object lens by an applicator with neutral detergent when the
signal level is low than specified value with the following checks.
•Abbreviation
MX: Mexican model
S-CURVE CHECK
Procedure:
1. Connect an oscilloscope to TP (FE) and TP (VC) on the CD
board (except MX) or BD board (MX).
2. Press the I/1button to turn the power on.
3. Load the disc (YEDS-18) and actuate the focus search. (In
consequence of open and close the disc tray, actuate the focus
search)
4. Confirm that the oscilloscope waveform (S-curve) is
symmetrical betweenA and B.And confirm peak to peak level
within 3 ±0.5 Vp-p.
Note: •Try to measure several times to make sure than the ratio ofA : B
or B : A is more than 10 : 7.
•Take sweep time as long as possible and light up the brightness
to obtain best waveform.
Connecting Location: CD board (except MX)
BD board (MX)
RFAC LEVEL CHECK
Procedure:
1. Connect an oscilloscope to TP (RFACO) and TP (VC) on the
CD board (except MX) or BD board (MX).
2. Press the I/1button to turn the power on.
3. Load the disc (YEDS-18) and playback.
4. Confirmthatoscilloscope waveformis clearandcheck ifRFAC
signal level is correct or not.
Note: ClearRFACsignal waveform meansthat the shape “ ◊” can beclearly
distinguished at the center of the waveform.
Connecting Location: CD board (except MX)
BD board (MX)
CD board (except MX)
BD board (MX) oscilloscop
e
TP(FE)
TP(VC)
symmetry
S-curve waveform
within 3
± 0.5 Vp-
p
A
B
TP(RFACO)
CD board (except MX)
BD board (MX) oscilloscope
TP(VC)
RF signal waveform VOLT/DIV : 200mV
TIME/DIV : 500ns
level : 1.3
± 0.3 Vp-
p
– CD BOARD (Conductor Side) (except MX) –
– BD BOARD (Conductor Side) (MX) –
TP
(VC)
TP
(FE)
TP
(RFACO)
IC101