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Photo: HCD-GT55

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2008I05-1
© 2008.09

E Model

HCD-GT22/GT44/GT55

Australian Model

HCD-GT22/GT44

•

HCD-GT22 is the amplifier, USB, CD player, tape
deck and tuner section in MHC-GT22/GT22BP.

•

HCD-GT44 is the amplifier, USB, CD player, tape
deck and tuner section in MHC-GT44/GT44BP.

•

HCD-GT55 is the amplifier, USB, CD player, tape
deck and tuner section in MHC-GT55/GT55BP.

Model Name Using Similar Mechanism

NEW

CD

CD Mechanism Type

CDM74KF-K6BD91UR-WOD or

CDM74KFV-K6BD91UR-WOD

Section

Base Unit Name

BU-K6BD91UR-WOD74

Optical Pick-up Block Name

KSM-213DCP

TAPE

Model Name Using Similar Mechanism

NEW

Section

Tape Transport Mechanism Type

CWN42FF609

The following are measured at AC 120, 127, 
220, 240V 50/60Hz
Front speaker

Power output (rated): 110 W + 110 W 
(at 6 

Ω

, 1 kHz, 1% THD)

RMS output power (reference): 
200 W + 200 W (per channel at 6 

Ω

, 

1 kHz, 10% THD)

Subwoofer

RMS output power (reference): 190 W
(at 6 

Ω

, 80 Hz, 10% THD)

The following are measured at AC 120, 127, 
220, 240V 50/60Hz
Front speaker

Power output (rated): 90 W + 90 W 
(at 6 

Ω

, 1 kHz, 1% THD)

RMS output power (reference): 
150 W + 150 W (per channel at 6 

Ω

, 

1 kHz, 10% THD)

Subwoofer

RMS output power (reference): 150 W 
(at 6 

Ω

, 80 Hz, 10% THD)

The following are measured at AC 120, 127, 
220, 240V 50/60Hz

Power output (rated): 110 W + 110 W 
(at 6 

Ω

, 1 kHz, 1% THD)

RMS output power (reference): 
200 W + 200 W (per channel at 6 

Ω

, 

1 kHz, 10% THD)

AUDIO (phono jack): voltage 250 mV, 
impedance 47 kilohms
MIC (phone jack): sensitivity 1 mV, 
impedance 10 kilohms

 (USB) port: Type A

PHONES (stereo mini jack): accepts 
headphones of 8 

Ω

 or more

SPEAKER: accepts impedance of 6 to 16 

Ω

SUB WOOFER OUT (HCD-GT55/GT44 
only): accepts impedance of 6 to 16 

Ω

Supported bit rate

MP3 (MPEG 1 Audio Layer-3): 
32 – 320 kbps, VBR

Sampling frequencies

MP3 (MPEG 1 Audio Layer-3): 
32/44.1/48 kHz

Transfer speed

Full-Speed

Supported USB device

Mass Storage Class

Maximum current

500 mA

System: Compact disc and digital audio 
system
Laser: Semiconductor laser (

λ

=770 –  

810 nm)
Emission duration: continuous
Frequency response: 20 Hz – 20 kHz
Signal-to-noise ratio: More than 90 dB
Dynamic range: More than 88 dB

2

•

Never reuse a disconnected chip component.

•

Notice that the minus side of a tantalum capacitor may be

damaged by heat.

•

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.

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

 0

0

is classified 
as a CLASS 1 
LASER product. 
This marking is 
located on the rear 
exterior.

This appliance 

Recording system: 4-track 2-channel, stereo
Frequency response: 50 – 13,000 Hz (

±

3 

dB), using Sony TYPE I cassettes

FM stereo, FM/AM superheterodyne tuner

FM tuner section:

Tuning range:

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

Latin American and Oceanian 
models:
530 – 1,710 kHz (with 10 kHz tuning 
interval)
531 – 1,710 kHz (with 9 kHz tuning 
interval)

Other models:
530 – 1,610 kHz (with 10 kHz tuning 
interval)
531 – 1,602 kHz (with 9 kHz tuning 
interval)

Antenna: AM loop antenna, external 
antenna terminal
Intermediate frequency: 450 kHz

Power requirements

Oceanian model: AC 230 – 240 V, 
50/60 Hz
Mexican model: AC 127 V, 60 Hz
Argentine model: AC 220 V, 50/60 Hz
Other models: AC 120, 220 or 
230 – 240 V, 50/60 Hz, Adjustable 
with voltage selector

Power consumption

HCD-GT55: 225 W
HCD-GT44: 250 W
HCD-GT22: 150 W

Dimensions (w/h/d) (excl. speakers)

HCD-GT55:
Approx. 280 

×

 365 

×

 425 mm

HCD-GT44/GT22:
Approx. 280 

×

 325 

×

 425 mm

Mass (excl. speakers)

HCD-GT55: 10.5 kg
HCD-GT44/GT22: 10.0 kg

Design and specifications are subject to 
change without notice.

3

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

4

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

6

3-1.

Disassembly Flow ...........................................................

7

3-2.

Case (Side-L), Case (Side-R) ..........................................

8

3-3.

Case (Top) .......................................................................

8

3-4.

Lid (CD) ..........................................................................

9

3-5.

CD Mechanism Deck, USB board ..................................

9

3-6.

Front Panel Block ............................................................ 10

3-7.

Mecha Deck (CWN42FF609) ......................................... 10

3-8.

Back Panel Block ............................................................ 11

3-9.

MAIN Board .................................................................... 11

3-10. CD Board ......................................................................... 12
3-11. DRIVER Board, SW Board ............................................. 12
3-12. Optical Pick-up Block (KSM-213D) ............................... 13
3-13. SENSOR Board ............................................................... 13
3-14. MOTOR (TB) Board ....................................................... 14
3-15. MOTOR (LD) Board ....................................................... 14

.............................................................. 15

....................... 19

......................... 20

7-1.

Block Diagram – CD SERVO, USB Section – ............... 23

7-2.

Block Diagram – MAIN Section – .................................. 24

7-3.

Block Diagram – AMP Section – .................................... 25

7-4.

Block Diagram – PANEL, POWER AMP Section – ....... 26

7-5.

Printed Wiring Board – CD Board – ............................... 28

7-6.

Schematic Diagram – CD Board – .................................. 29

7-7.

Printed Wiring Boards – CHANGER Section – .............. 30

7-8.

Schematic Diagram – CHANGER Section – .................. 31

7-9.

Printed Wiring Board – USB Board – ............................. 32

7-10. Schematic Diagram – USB Board – ................................ 33
7-11. Printed Wiring Board – TC Board – ................................ 34
7-12. Schematic Diagram – TC Board – .................................. 35
7-13. Printed Wiring Boards – MAIN Section – ...................... 37
7-14. Schematic Diagram – MAIN Section (1/4) – .................. 38
7-15. Schematic Diagram – MAIN Section (2/4) – .................. 39
7-16. Schematic Diagram – MAIN Section (3/4) – .................. 40
7-17. Schematic Diagram – MAIN Section (4/4) – .................. 41
7-18. Printed Wiring Board – MIC Board – ............................. 42
7-19. Schematic Diagram – MIC Board – ................................ 43
7-20. Printed Wiring Board

– AMP Board (GT22/GT55) – ........................................ 44

7-21. Schematic Diagram – AMP Board (GT22/GT55) – ........ 45
7-22. Printed Wiring Board – AMP Board (GT44) – ............... 46
7-23. Schematic Diagram – AMP Board (GT44) – .................. 47

7-24. Printed Wiring Boards

– SUB WOOFER Section (GT44/GT55) – ..................... 48

7-25. Schematic Diagram

– SUB WOOFER Section (GT44/GT55) – ..................... 49

7-26. Printed Wiring Boards – PANEL Section – ..................... 50
7-27. Schematic Diagram – PANEL Section – ......................... 51
7-28. Printed Wiring Boards – KEY Section – ......................... 52
7-29. Schematic Diagram – KEY Section – ............................. 53
7-30. Printed Wiring Board

– TRANS Board (GT22/GT55) – .................................... 54

7-31. Schematic Diagram

– TRANS Board (GT22/GT55) – .................................... 55

7-32. Printed Wiring Board – TRANS Board (GT44) – ........... 56
7-34. Schematic Diagram – TRANS Board (GT44) – ............. 57

8-1.

Case Section .................................................................... 69

8-2.

KEY TOP Board Section ................................................. 70

8-3.

TC Mecha Deck Section .................................................. 71

8-4.

PANEL Board Section ..................................................... 72

8-5.

Front Panel Section ......................................................... 73

8-6.

MAIN Board Section ....................................................... 74

8-7.

POWER Board, SUB WOOFER Board Section ............. 75

8-8.

Chassis Section ................................................................ 76

8-9.

CD Mechanism Deck Section-1
(CDM74KF-K6BD91UR-WOD or
CDM74KFV-K6BD91UR-WOD) ................................... 77

8-10. CD Mechanism Deck Section-2

(CDM74KF-K6BD91UR-WOD or
CDM74KFV-K6BD91UR-WOD) ................................... 78

................................ 79

4

Model

Power voltage indication

GT22: E2, E3, E51

AC: 120V/220V/230-240V - 50/60Hz 150W

GT22: E13, AUS

AC: 230-240V - 50/60Hz 150W

GT22: MX

ca-127V 60Hz 150W

GT22: AR

ca 220V - 50/60Hz 150W

GT44: E13, AUS

AC: 230-240V - 50/60Hz 250W

GT44: E2, E3, E51

AC: 120V/220V/230-240V - 50/60Hz 250W

GT44: MX

ca-127V 60Hz 250W

GT44: AR

ca 220V - 50/60Hz 250W

GT55: E2, E3, E51

AC: 120V/220V/230-240V - 50/60Hz 225W

GT55: MX

ca-127V 60Hz 225W

GT55: AR

ca 220V - 50/60Hz 225W

•

Abbreviation
AR

: Argentina model

AUS

: Australian model

E2

: 120V AC Area in E model

E3

: 240V AC Area in E model

E13

: 220V - 230V AC Area in E model

E51

: Chilean and Peruvian models

MX

: Mexican model

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.

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.

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 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.

The disc table lock function for the antitheft of an demonstration
disc in the store is equipped.

1. Press the  

I

/1

  button to turn the power on.

2. Press the  

CD

  button to select “CD”.

3. While pressing the

x

button, press the 

Z

button until

“UNLOCKED” displayed on the fluorescent indicator tube
(around 5 seconds).

When “LOCKED” is displayed, the antitheft lock is not released by
turning power on/off with the

I/

1

button.

Power Voltage
Indication

1

Turn the gear (loading A)
to the direction of the arrow.

2