HCD-BX7DAB - Sony Audio Service Manual (repair manual)

Model Name Using Similar Mechanism

HCD-CBX3

Base Unit Name

BU-K6BD90U-WOD

Optical Pick-up Block Name

KSM-213DCP

– Continued on next page –

2007G05-1
© 2007.07

UK Model

•

HCD-BX7DAB is the amplifier, USB, CD player and
tuner section in CMT-BX7DAB.

• “WALKMAN” and “WALKMAN” logo are registered

trademarks of Sony Corporation.

• MICROVAULT is a trademark of Sony Corporation.
• ATRAC, ATRAC3, ATRAC3plus and their logos are

trademarks of Sony Corporation.

• U.S. and foreign patents licensed from Dolby

Laboratories.

• MPEG Layer-3 audio coding technology and patents

licensed from Fraunhofer IIS and Thomson.

DIN power output (rated):  
18 + 18 watts (6 ohms at 1 kHz, DIN)
Continuous RMS power output (reference): 
25 + 25 watts (6 ohms at 1 kHz, 10% THD)
Music power output (reference):  
38 + 38 watts (6 ohms at 1 kHz, 10% THD)

Inputs:

AUDIO IN (stereo mini jack): 
voltage 250 mV, impedance 
47 kilohms

 (USB) port: Type A, maximum 

current 500 mA

Outputs:

PHONES (stereo mini jack): accepts 
headphones of 8 ohms or more
SPEAKER: accepts impedance of 6 to 
16 ohms

Supported bit rate

MP3 (MPEG 1 Audio Layer-3): 
32 – 320 kbps, VBR
ATRAC: 48 – 352 kbps 
(ATRAC3plus), 66/105/132 kbps 
(ATRAC3)
WMA: 32 – 192 kbps, VBR
AAC: 48 – 320 kbps

Sampling frequencies

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

System: Compact disc and digital audio 
system
Laser Diode Properties

Emission duration: continuous
Laser Output*: Less than 44.6

µ

W

*This output is the value measurement 

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

Frequency response: 20 Hz – 20 kHz
Signal-to-noise ratio: More than 90 dB
Dynamic range: More than 90 dB

DAB tuner section:

Frequency range*

Band-III: 174.928 (5A) – 239.200 
(13F) MHz

* For details, see “DAB frequency table”.

Antenna: FM/DAB lead antenna
Antenna terminal: 75 ohms, F female

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: 531 – 1,602 kHz (with 9 kHz 
tuning interval)
Antenna: AM loop antenna, external 
antenna terminal
Intermediate frequency: 450 kHz

2

•

Never reuse a disconnected chip component.

•

Notice that the minus side of a tantalum capacitor may be
damaged by heat.

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

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

This appliance is 

 0

0

DAB frequency table (Band-III)

Frequencies are displayed to two decimal 
places on this system.

174.928 MHz 5A

209.936 MHz 10A

176.640 MHz 5B

211.648 MHz 10B

178.352 MHz 5C

213.360 MHz 10C

180.064 MHz 5D

215.072 MHz 10D

181.936 MHz 6A

216.928 MHz 11A

183.648 MHz 6B

218.640 MHz 11B

185.360 MHz 6C

220.352 MHz 11C

187.072 MHz 6D

222.064 MHz 11D

188.928 MHz 7A

223.936 MHz 12A

190.640 MHz 7B

225.648 MHz 12B

192.352 MHz 7C

227.360 MHz 12C

194.064 MHz 7D

229.072 MHz 12D

195.936 MHz 8A

230.784 MHz 13A

197.648 MHz 8B

232.496 MHz 13B

199.360 MHz 8C

234.208 MHz 13C

201.072 MHz 8D

235.776 MHz 13D

202.928 MHz 9A

237.488 MHz 13E

204.640 MHz 9B

239.200 MHz 13F

206.352 MHz 9C

208.064 MHz 9D

Power requirements: 230 V AC, 50/60 Hz
Power consumption: 65 watts
Dimensions (w/h/d) (excl. speakers): 
Approx. 200 

×

 132 

×

 298 mm

Mass (excl. speakers): Approx. 3.7 kg

Design and specications are subject to 
change without notice.

3

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

4

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

6

3-1.

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

7

3-2.

Panel (Side L/R) ..............................................................

7

3-3.

LID (CD) Assy ................................................................

8

3-4.

Panel (Top) ......................................................................

8

3-5.

MAIN Board, Shield Plate (PWB Main) .........................

9

3-6.

DAB Board, Module (DAB Tuner) ................................. 10

3-7.

Front Panel/Headphone Boards, Panel (Front) Assy ....... 10

3-8.

D.C. Fan (M301), Panel (Rear) ....................................... 11

3-9.

Power Transformer (T1) .................................................. 11

3-10. Loading Mechanism Block ............................................. 12
3-11. Base Unit ......................................................................... 12
3-12. Belt .................................................................................. 13
3-13. OP Base Assy (KSM-213D), CD board .......................... 13

.............................................................. 14

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

6-1.

Block Diagram – CD SERVO Section – ......................... 17

6-2.

Block Diagram – TUNER, USB, DAB Section – ........... 18

6-3.

Block Diagram – MAIN Section – .................................. 19

6-4.

Block Diagram
– PANEL, POWER SUPPLY Section – .......................... 20

6-5.

Printed Wiring Boards – CD Section – ........................... 22

6-6.

Schematic Diagram – CD Board – .................................. 23

6-7.

Printed Wiring Board – USB Board – ............................. 24

6-8.

Schematic Diagram – USB Board – ................................ 25

6-9.

Printed Wiring Board – DAB Board – ............................. 26

6-10. Schematic Diagram – DAB Board – ............................... 27
6-11. Printed Wiring Boards – REGULATOR Section – ......... 28
6-12. Schematic Diagram – REGULATOR Section – .............. 28
6-13. Printed Wiring Board – MAIN Section – ........................ 29
6-14. Schematic Diagram – MAIN Section (1/4) – .................. 30
6-15. Schematic Diagram – MAIN Section (2/4) – .................. 31
6-16. Schematic Diagram – MAIN Section (3/4) – .................. 32
6-17. Schematic Diagram – MAIN Section (4/4) – .................. 33
6-18. Printed Wiring Board – AMP Board – ............................ 34
6-19. Schematic Diagram – AMP Board – ............................... 35
6-20. Printed Wiring Boards – SPEAKER Section – ............... 36
6-21. Schematic Diagram – SPEAKER Section – .................... 37
6-22. Printed Wiring Boards – PANEL Section – ..................... 38
6-23. Schematic Diagram – PANEL Section – ......................... 39
6-24. Printed Wiring Board – POWER Board – ....................... 40
6-25. Schematic Diagram – POWER Board – .......................... 41

7-1.

Panel Section ................................................................... 52

7-2.

Front Panel Section ......................................................... 53

7-3.

Main Section .................................................................... 54

7-4.

POWER Board Section ................................................... 55

7-5.

Loading Mechanism Section ........................................... 56

7-6.

Base Unit Section (BU-K6BD90U-WOD) ..................... 57

................................ 58

4

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.

1. Press the

I/

1

button to turn the power on.

2. Press the [CD] button on the remote commander to select “CD”.
3. Press two buttons of  [   /CANCEL] and

Z

for 5 seconds.

4. The message “UNLOCKED” is displayed on the liquid crystal

display and the disc tray is unlocked.

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

I

/1 button.

x