HCD-EC69T, HCD-EC79T, HCD-EC99T, MHC-EC69T, MHC-EC79T, MHC-EC99T - Sony Audio Service Manual (repair manual)

2009E05-1

© 

2009.05

•  HCD-EC69T is the amplifi er, USB, CD player, 

tape deck and tuner section in MHC-EC69T.

•  HCD-EC79T is the amplifi er, USB, CD player, 

tape deck and tuner section in MHC-EC79T.

•  HCD-EC99T is the amplifi er, USB, CD player, 

tape deck and tuner section in MHC-EC99T.

Photo: HCD-EC79T

•  “WALKMAN” and “WALKMAN” logo are registered trade-

marks of Sony Corporation.

•  MICROVAULT is a trademark of Sony Corporation.
•  MPEG Layer-3 audio coding technology and patents licensed 

from Fraunhofer IIS and Thomson.

•  Windows Media is a registered trademark of Microsoft 

Corporation in the United States and/or other countries.

CD
Section

Model Name Using Similar Mechanism

HCD-EC78

Mechanism Type

CDM88A-K6BD90-WOD

Optical Pick-up Block Name

KSM-213DCP

Tape deck 
Section

Model Name Using Similar Mechanism

HCD-EC78

Tape Transport Mechanism Type

TCM-J1 or 
CS-21SC-900TP

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

Front Speaker:
Power output (rated):

Low channel
50 W + 50 W (at 8 Ω, 1 kHz, 1% 
THD)
High channel
50 W + 50 W (at 8 Ω, 8 kHz, 1% 
THD)

RMS output power (reference):

Low channel
65 W + 65 W (per channel at 8 Ω,  
1 kHz, 10% THD)
High channel
65 W + 65 W (per channel at 8 Ω,  
8 kHz, 10% THD)

Subwoofer:
RMS output power (reference):

90 W (at 4 Ω, 80 Hz, 10% THD)

Power output (rated):

Low channel
55 W + 55 W (at 8 Ω, 1 kHz, 1% 
THD)
High channel
55 W + 55 W (at 8 Ω, 8 kHz, 1% 
THD)

RMS output power (reference):

Low channel
75 W + 75 W (per channel at 8 Ω,  
1 kHz, 10% THD)
High channel
75 W + 75 W (per channel at 8 Ω,  
8 kHz, 10% THD)

Power output (rated):

50 W + 50 W (at 6 Ω, 1 kHz, 1% 
THD)

RMS output power (reference):

70 W + 70 W (per channel at 6 Ω,  
1 kHz, 10% THD)

PC IN (stereo mini jack):

Sensitivity 800 mV, impedance 
22 kilohms

PHONES (stereo mini jack): 

accepts headphones with an 
impedance of 8 Ω or more

SPEAKER: impedance

HCD-EC99T/EC79T: 
8 Ω
HCD-EC69T: 6 Ω

SUBWOOFER (HCD-EC99T only): 

impedance 4 Ω

Supported bit rate:

MP3 (MPEG 1 Audio Layer-3)/
WMA/AAC: 
32   320 kbps, VBR

Sampling frequencies:

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

 (USB) port: 

Maximum current:
500 mA

System: 

Compact disc and digital audio 
system

Laser Diode Properties

Emission Duration: Continuous
Laser Output*: Less than 44.6μW
* 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 88 dB

Recording system: 4-track 2-channel, stereo

FM stereo, FM/AM superheterodyne tuner
Antenna:

FM lead antenna
AM loop antenna

FM tuner section:
Tuning range:

87.5   108.0 MHz (50 kHz step)

Intermediate frequency: 10.7 MHz

AM tuner section:
Tuning range:

531   1,602 kHz
(with 9 kHz tuning interval)
530   1,610 kHz
(with 10 kHz tuning interval)

Intermediate frequency: 450 kHz

Power requirements:

AC 120, 220, 230 – 240 V, 50/60 Hz, 
adjustable with voltage selector

Power consumption

HCD-EC99T: 175 W
(0.5 W at the Power Saving Mode)
HCD-EC79T: 170 W
(0.5 W at the Power Saving Mode)
HCD-EC69T: 110 W
(0.5 W at the Power Saving Mode)

Dimensions (w/h/d) (excl. speakers)

Approx. 200 × 306 × 415 mm

Mass (excl. speakers)

HCD-EC99T: Approx. 6.8 kg
HCD-EC79T: Approx. 6.7 kg
HCD-EC69T: Approx. 5.7 kg

Design and specifications are subject to 
change without notice.

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

3

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

6

3-1. Disassembly 

Flow 

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

3-2.  Side Panel (L)/(R) ...........................................................   8
3-3.  Top Panel Block ..............................................................   9
3-4.  Tape Mechanism Deck ....................................................   9
3-5. MAIN 

Board 

...................................................................  10

3-6.  Front Panel Block ...........................................................   10
3-7.  Back Panel Block ............................................................   11
3-8.  CD Mechanism Block .....................................................   11
3-9. Base 

Unit 

.........................................................................  12

3-10.  OP Base Assy (KSM-213D) ...........................................   12
3-11. Belt (DLM3A) ................................................................   13

TEST  MODE 

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

ADJUSTMENTS 

 ........................   18

ADJUSTMENTS 

 ........................   18

7-1.  Block Diagram - CD, TUNER Section - ........................   22
7-2.  Block Diagram - MAIN Section - ...................................   23
7-3. Block 

Diagram 

 

- PANEL, POWER SUPPLY Section - ...........................   24

7-4.  Printed Wiring Board - CD Board - ................................   26
7-5.  Schematic Diagram - CD Board - ...................................   27
7-6.  Printed Wiring Board - USB Board - ..............................   28
7-7.  Schematic Diagram - USB Board - .................................   29
7-8.  Printed Wiring Board - DECK Board (SUFFIX-11) - ....   30
7-9.  Printed Wiring Board - DECK Board (SUFFIX-12) - ....   30
7-10.  Schematic Diagram - DECK Board - .............................   31
7-11.  Schematic Diagram - MAIN Board (1/2) - .....................   32
7-12.  Schematic Diagram - MAIN Board (2/2) - .....................   33
7-13.  Printed Wiring Board - MAIN Board - ...........................   34
7-14.  Printed Wiring Boards - AMP Section -..........................   35
7-15.  Schematic Diagram - 2CH-4CH AMP Board - ...............   36
7-16.  Schematic Diagram - 3CH AMP Board -........................   37
7-17.  Printed Wiring Board - PANEL Board - .........................   38
7-18.  Schematic Diagram - PANEL Board - ............................   39
7-19. Printed Wiring Boards 
 

- AUDIO IN/OUT, KEY, POWER SUPPLY Section - ...   40

7-20. Schematic Diagram 
 

- AUDIO IN/OUT, KEY, POWER SUPPLY Section - ...   41

 

8-1. Panel 

Section 

...................................................................  49

8-2.  Tape Deck Section ..........................................................   50
8-3.  Front Panel Section .........................................................   51
8-4. Chassis 

Section 

...............................................................  52

8-5. Main 

Section 

...................................................................  53

8-6.  CD Mechanism Section (CDM88A-K6BD90-WOD) ....   54

  ..............................   55

Accessories are given in the last of the electrical parts list.

NOTES  ON  CHIP  COMPONENT  REPLACEMENT
• 

Never reuse a disconnected chip component.

• 

Notice that the minus side of a tantalum capacitor may be dam-
aged 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.

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

This appliance is classifi ed as 
a CLASS 1 LASER product.
This marking is located on the 
rear or rear exterior.

0  OR  DOTTED  LINE  

0  ON  THE  SCHEMATIC  DIAGRAMS  AND  IN  

Note: Refer to the servicing notes “DECK BOARD DISCRIMI-

NATION” (page 3) for how to distinguish SUFFIX-11 and 
SUFFIX-12.

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.

The laser diode in the optical pick-up block may suffer electrostat-
ic 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.

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

x

] button, press the [

Z

] 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 turn-

ing power on/off with the [?/1] button.

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.

DECK  BOARD  DISCRIMINATION
In this set, the DECK board has been changed in the midway of 
production.
Repair after distinguishing each type set to doing the repair refer-
ring to the following.