HCD-GPX555, HCD-GPX888 - Sony Audio Service Manual (repair manual)

2015H80-1

© 

2015.08

•  HCD-GPX555 is the amplifi er, USB, CD player, 

Bluetooth, NFC and tuner section in MHC-GPX555.

•  HCD-GPX888 is the amplifi er, USB, CD player, 

Bluetooth, NFC and tuner section in MHC-GPX888.

Photo: HCD-GPX888

CD Section

Model Name Using 
Similar Mechanism

HCD-GPX33

CD Mechanism Type

CDM90-DVBU204//M

Optical Pick-up Name

CMS-S76RFS7G

•  “WALKMAN” and “WALKMAN” logo are registered trademarks of Sony Corporation.
•  MPEG Layer-3 audio coding technology and patents licensed from Fraunhofer IIS and Thomson.
•  Windows Media is either a registered trademark or trademark of Microsoft Corporation in the United States and/or 

other countries.

•  This product is protected by certain intellectual property rights of Microsoft Corporation. Use or distribution of 

such technology outside of this product is prohibited without a license from Microsoft or an authorized Microsoft 
subsidiary.

• The 

®

 word mark and logos are registered trademarks owned by Bluetooth SIG, Inc. and any use of such 

marks by Sony Corporation is under license. Other trademarks and trade names are those of their respective owners.

•  The N Mark is a trademark or registered trademark of NFC Forum, Inc. in the United States and in other countries.
•  Android™ is a trademark of Google Inc.
•  Google Play™ is a trademark of Google Inc.
•  iPhone and iPod touch are trademarks of Apple Inc., registered in the U.S. and other countries. App Store is a service 

mark of Apple Inc.

•  “Made for iPod” and “Made for iPhone” mean that an electronic accessory has been designed to connect specifically 

to iPod or iPhone, respectively, and has been certified by the developer to meet Apple performance standards. Apple is 
not responsible for the operation of this device or its compliance with safety and regulatory standards. Please note that 
the use of this accessory with iPod or iPhone may affect wireless performance.

•  All other trademarks and registered trademarks are of their respective holders. In this manual, ™ and ® marks are not 

specified.

POWER OUTPUT AND TOTAL HARMONIC 
DISTORTION:
(USA model only)
With 4 ohm loads, both channels driven, from 
120 – 10,000 Hz; rated 180 watts per channel 
minimum RMS power, with no more than 
0.7% total harmonic distortion from 250 
milliwatts to rated output.

Amplifi er section
The following are measured at
USA model:
 

AC 120 V, 60 Hz

Mexican model:
 

AC 120 V – 240 V, 60 Hz

Chilean and Bolivian models:
 

AC 220 V – 240 V, 50 Hz 

Other models:
 

AC 120 V – 240 V, 50/60 Hz

MHC-GPX888
Front speaker
 

Power Output (rated):

 350 

W 

+ 

350 W (at 4 ohms, 1 kHz, 

 1% 

THD)

 

RMS output power (reference):

 

600 W + 600 W (per channel at 

 4 

ohms, 

1 kHz)

LBT-GPX555/MHC-GPX555
Front speaker
 

Power Output (rated):

 

350 W + 350 W (at 4 ohms, 1 kHz,

 1% 

THD)

 

RMS output power (reference):

 

600 W + 600 W (per channel at 4 ohms,

 1 

kHz)

Subwoofer
 

RMS output power (reference):

 

600 W (4 ohms, 100 Hz)

Inputs
AUDIO IN 1/PARTY CHAIN IN L/R
 

Voltage 2 V, impedance 47 kilohms

AUDIO IN 2 L/R
 

Voltage 2 V, impedance 47 kilohms

MIC (MHC-GPX888 only)
 

Sensitivity 1 mV, impedance

 10 

kilohms

 (USB) A,   (USB) B, port

 Type 

A

Outputs
AUDIO OUT/PARTY CHAIN OUT L/R
 

Voltage 2 V, impedance 1 kilohm

USB section
Supported bit rate
 WMA:
 

48 kbps – 192 kbps, VBR, CBR

 AAC:
 

48 kbps – 320 kbps, VBR, CBR

Sampling frequencies
 

WMA: 44.1 kHz

 AAC: 

44.1 kHz

Supported USB device
 

Mass Storage Class

Maximum current
 500 

mA

Disc/USB section
Supported bit rate
 MPEG1 

Layer-3:

 

32 kbps – 320 kbps, VBR

 MPEG2 

Layer-3:

 

8 kbps – 160 kbps, VBR

 MPEG1 

Layer-2:

 

32 kbps – 384 kbps, VBR

Sampling frequencies
 MPEG1 

Layer-3:

 

32 kHz/44.1 kHz/48 kHz

 MPEG2 

Layer-3:

 

16 kHz/22.05 kHz/24 kHz

 MPEG1 

Layer-2:

 

32 kHz/44.1 kHz/48 kHz

Disc player section
System
 

Compact disc and digital audio system

Laser Diode Properties
 

Emission Duration: Continuous

 

Laser Output*: Less than 44.6 

W

 

* This output is the value measurement 

at a distance of 200 mm from the 
objective lens surface on the Optical 
Pick-up Block with 7 mm aperture.

Frequency response
 

20 Hz – 20 kHz

Signal-to-noise ratio
 

More than 90 dB

Dynamic range
 

More than 88 dB

Tuner section
FM stereo, FM/AM superheterodyne tuner
Antenna:
 

FM lead antenna

 

AM loop antenna

FM tuner section
Tuning range
 USA 

model:

 

87.5 MHz – 108.0 MHz 

 

(100 kHz step)

 Other 

models:

 

87.5 MHz – 108.0 MHz (50 kHz step)

AM tuner section
Tuning range
 

Pan American and Australian models:

 

531 kHz – 1,710 kHz (9 kHz step)

 

530 kHz – 1,710 kHz (10 kHz step)

 Other 

models:

 

531 kHz – 1,602 kHz (9 kHz step)

 

530 kHz – 1,610 kHz (10 kHz step)

Bluetooth section
Communication system
 

Bluetooth Standard version 3.1

Output
 

Bluetooth Standard Power Class 2

Maximum communication range
 

Line of sight approx. 10 m

1)

Frequency band
 

2.4 GHz band (2.4000 GHz – 2.4835 GHz)

Modulation method
 

FHSS (Freq Hopping Spread Spectrum)

Compatible Bluetooth profiles

2)

 

A2DP (Advanced Audio Distribution 

 Profile)
 

AVRCP 1.3 (Audio Video Remote 

 Control 

Profile)

 

SPP (Serial Port Profile)

Supported codecs
 

SBC (Sub Band Codec)

 

AAC (Advanced Audio Coding)

1)

 The actual range will vary depending on 

factors such as obstacles between devices, 
magnetic fields around a microwave oven, 
static electricity, reception sensitivity, 
antenna’s performance, operating system, 
software application, etc.

2)

 Bluetooth standard profiles indicate the 

purpose of Bluetooth  communication 
between devices.

– Continued on next page –

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  CHECK-OUT
After correcting the original service problem, perform the 
following safety check 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  TEST
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 microamperes.). 
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. Follow the manufacturers’ 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 AC voltmeter. The “limit” indication 
is 0.75 V, so analog meters must have an accurate low-voltage 
scale. The Simpson 250 and Sanwa SH-63Trd are examples 
of a passive VOM that is suitable. Nearly all battery operated 
digital multimeters that have a 2 V AC range are suitable. (See 
Fig. A)

0  OR  DOTTED  LINE  

0  ON  THE  SCHEMATIC  DIAGRAMS  AND  IN  

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

General
Power requirements
 USA 

model:

 

AC 120 V, 60 Hz

 Mexican 

model:

 

AC 120 V – 240 V, 60 Hz

 

Chilean and Bolivian models:

 

AC 220 V – 240 V, 50 Hz

 Other 

models:

 

AC 120 V – 240 V, 50/60 Hz

Power consumption
 MHC-GPX888: 

360 

W

 LBT-GPX555/MHC-GPX555: 

280 

W

Dimensions (w/h/d) (excl. speakers)
(Approx.)
 MHC-GPX888:
 

294 mm × 361 mm × 331 mm

 (11 

5

⁄

8

 in × 14 

1

⁄

4

 in × 13 

1

⁄

8

 in) 

 LBT-GPX555/MHC-GPX555:
 

294 mm × 361 mm × 325 mm

 (11 

5

⁄

8

 in × 14 

1

⁄

4

 in × 12 

7

⁄

8

 in)

Mass (excl. speakers) (Approx.)
 

5.4 kg (11 lb 15 oz)

Supplied accessories
 

Remote control (1)

 

R6 (Size AA) batteries (2)

 

FM lead/AM loop antenna (1)

 

Spacer (2) (MHC-GPX888 only)

 

Speaker pads (16) (MHC-GPX888 only)

Design and specifi cations are subject to change without notice.

This appliance is classified as a CLASS 1 
LASER product by IEC60825-1:2007. This 
marking is located on the rear exterior.

 ................................................  

4

2-1. Disassembly 

Flow 

...........................................................   7

2-2.  Side-L Panel, Side-R Panel, Top Panel ...........................   8
2-3. Loading 

Panel 

.................................................................   8

2-4.  Front Panel Section .........................................................   9
2-5.  CD Mechanism Section (CDM90-DVBU204//M) .........   9
2-6.  Back Panel Section .........................................................   10
2-7.  MB Board, DAMP Board ...............................................   10
2-8.  SWITCHING REGULATOR (3H401W) .......................   11
2-9.  Service Optical Device, Wire (Flat Type) .......................   12

 .............................................................   13

 ..........................................   16

 ...........................................   17

6-1.  Block Diagram - RS SERVO, USB Section - .................   23
6-2.  Block Diagram - MAIN Section - ...................................   24
6-3.  Block Diagram - AMP Section - .....................................   25
6-4. Block 

Diagram 

- PANEL/POWER SUPPLY Section - ............................   26

6-5. Printed 

Wiring 

Board 

- MB Board (Component side) - .....................................   28

6-6. Printed 

Wiring 

Board 

- MB Board (Conductor side) - .......................................   29

6-7.  Schematic Diagram - MB Board (1/9) - .........................   30
6-8.  Schematic Diagram - MB Board (2/9) - .........................   31
6-9.  Schematic Diagram - MB Board (3/9) - .........................   32
6-10.  Schematic Diagram - MB Board (4/9) - .........................   33
6-11.  Schematic Diagram - MB Board (5/9) - .........................   34
6-12.  Schematic Diagram - MB Board (6/9) - .........................   35
6-13.  Schematic Diagram - MB Board (7/9) - .........................   36
6-14.  Schematic Diagram - MB Board (8/9) - .........................   37
6-15.  Schematic Diagram - MB Board (9/9) - .........................   38
6-16.  Printed Wiring Board - DAMP Board - ..........................   39
6-17.  Schematic Diagram - DAMP Board (1/2) - ....................   40
6-18.  Schematic Diagram - DAMP Board (2/2) - ....................   41

6-19. Printed Wiring Board 

- FL Board (Component side) - .......................................   42

6-20. Printed Wiring Board 

- FL Board (Conductor side) -.........................................   43

6-21.  Schematic Diagram - FL Board - ....................................   44
6-22.  Printed Wiring Board - DJ KEYS Board -  .....................   45
6-23.  Schematic Diagram - DJ KEYS Board - ........................   46
6-24.  Printed Wiring Board - USB Board - ..............................   47
6-25.  Schematic Diagram - USB Board - .................................   48
6-26.  Printed Wiring Board - TUNER Board - ........................   49
6-27.  Schematic Diagram - TUNER Board - ...........................   50

7-1.  Side Panel Section ..........................................................   65
7-2.  Back Panel Section .........................................................   66
7-3.  Front Panel Section .........................................................   67
7-4.  MB Board Section ..........................................................   68
7-5. Chassis 

Section 

...............................................................  69

7-6.  CD Mechanism Section

(CDM90-DVBU204//M) ................................................   70

 ...............................   71

The laser diode in the optical pick-up block may suffer electro-
static 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 fl exible board is easily damaged and should be handled with 
care.

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)

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 viscous (sticky, less prone to fl ow) 
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.

NOTE  OF  REPLACING  THE  IC001,  IC002,  IC105,  
IC106  AND  IC302  ON  THE  MB  BOARD
IC001, IC002, IC105, IC106 and IC302 on the MB board cannot 
exchange with single. When these parts on the MB board are 
damaged, exchange the entire mounted board.

RELEASING  THE  DISC  TRAY  LOCK
The disc tray lock function for the antitheft of an demonstration 
disc in the store is equipped.

Releasing Procedure:
1. Press 

[

\

/1

] button to turn the power on.

2.  Press the [CD] button to select CD function.
3.  While pressing the [

x

] button, press the [BASS BAZUCA] 

button for more 5 seconds).

4.  The message “UNLOCKED” is displayed and the disc tray is 

unlocked.

Note: When 

“

LOCKED

”

 is displayed, the slot lock is not released by 

turning power on/off with the

 [

\

/1

]

 button.

GPX888: E2, E51

4-479-110-0[]

GPX555: E2, E51, EA3, AUS, E4

4-479-110-1[]

US

4-479-110-2[]

Mexican

4-479-110-3[]

NOTES  ON  LASER DIODE  EMISSION  CHECK
The laser beam on this model is concentrated so as to be focused 
on the disc refl ective 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.

FOR SERVICE

USE