DOWNLOAD Sony CMT-A50 / CMT-A70 Service Manual ↓ Size: 5.4 MB | Pages: 73 in PDF or view online for FREE

US Model

Canadian Model

Australian Model

CMT-A70

AEP Model

UK Model

CMT-A50/A70

E Model

CMT-A50

Photo: CMT-A50

2006B05-1
© 2006.02

US and foreign patents licensed from Dolby Laboratories.

System

Compact disc digital audio system

Laser diode properties

Material: GaAlAs
Wave length: 780 nm
Emission duration: Continuous
Laser output: Less than 44.6 

µW

(This output is the value measured at a distance of about
200 mm from the objective lens surface on the optical
pick-up block with 7 mm aperture.)

Spindle speed

400 r/min (rpm) to 1 000 r/min (rpm) (CLV)

Number of channels

2

Frequency response

20 - 20 000 Hz +0/–1 dB

Wow and flutter

Below measurable limit

Frequency range

FM 87.5 - 108 MHz
AM
US, Canadian models:  530 - 1 710 kHz
Other models: 531 - 1 611 kHz (9 kHz step)

530 - 1 610 kHz (10 kHz step)

IF

FM: 10.7 MHz
AM: 450 kHz

Aerials

FM:  Lead aerial
AM: Loop aerial

Recording system

4-track 2 channel stereo

Fast winding time

Approx. 112 s (sec.) with Sony cassette C-60

Frequency response

TYPE I (normal): 50 - 15 000 Hz

Speaker

Tweeter: 4 cm dia., 6 

Ω

Woofer: 13 cm dia., 6 

Ω

Passive radiator: 10 cm dia. (CMT-A50 only)

Input

LINE IN jack (stereo minijack)
Minimum input level 430 mV

Outputs

Headphones jack (stereo minijack):

For 8 - 64 

Ω impedance headphones

OPTICAL DIGITAL OUT (CD) (optical output
connector):

Wavelength: 630 - 690 nm

Maximum power output

CMT-A50: 20 W
CMT-A70: 60 W

Power requirements

For personal component system:

US, Canadian models: 120 V AC, 60 Hz
Korean model: 220 V AC, 60 Hz
Other models: 230 V AC, 50 Hz

For remote control:

3 V DC, 2 R03 (size AAA) batteries

Power consumption

CMT-A50: 50 W
CMT-A70: 100 W

Dimensions

Player:

Approx. 136 

× 151.8 × 204 mm (w/h/d)

(incl. projecting parts)

Speaker:

CMT-A50: Approx. 128 

× 287 × 215 mm (w/h/d)

(incl. projecting parts)
CMT-A70: Approx. 164 

× 267 × 255 mm (w/h/d)

(incl. projecting parts)

Ma

CMT-A50:

Player: Approx. 1.6 kg
Left speaker: Approx. 4.3 kg
Right speaker: Approx. 2.2 kg

CMT-A70:

Player: Approx. 1.6 kg
Left speaker: Approx. 5.6 kg
Right speaker: Approx. 2.9 kg

Supplied accessories

Remote control (1)
FM lead aerial (1)
AM loop aerial (1)
CD-ROM (SonicStage) (1)
SonicStage Installation/Operating Guide (1)

Design and specifications are subject to change without
notice.

POWER OUTPUT AND TOTAL HARMONIC
DISTORTION

With 6 

Ω loads, both channels driven from 100 -

10,000 Hz; rated 55 W per channel-minimum
RMS power, with no more than 10 % total
harmonic distortion in AC operation.

Model Name Using Similar Mechanism

NEW

CD

CD Mechanism Type

FLM-A50

Section

Optical Pick-up Block Name

KSM-213CCP or KSM-213RCP

Optical Pick-up Name

KSS-213C or KSS-213R

Tape deck

Model Name Using Similar Mechanism

NEW

Section

Tape Transport Mechanism Type

CMAL1Z252A

2

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.

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)

• 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.

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.

 0

0

1.5 k

Ω

0.15 

µ

F

AC
voltmeter
(0.75 V)

To Exposed Metal
Parts on Set

Earth Ground

0

3

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

4

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

6

3-1.

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

9

3-2.

Cabinet Rear .................................................................... 10

3-3.

CD Door .......................................................................... 10

3-4.

CD Mechanism Deck (FLM-A50) .................................. 11

3-5.

SUB Board ...................................................................... 11

3-6.

Top Case Assy ................................................................. 12

3-7.

MAIN Board .................................................................... 12

3-8.

CD Board ......................................................................... 13

3-9.

Tray .................................................................................. 13

3-10. Optical Pick-up Block

(KSM-213CCP or KSM-213RCP) .................................. 14

3-11. Optical Pick-up (KSS-213C) ........................................... 14
3-12. Optical Pick-up (KSS-213R) ........................................... 15
3-13. Tape Mechanism Deck (CMAL1Z252A) ........................ 15

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

Deck Section .................................................................... 18
CD Section ...................................................................... 19

6-1.

Block Diagram  – SERVO Section – ............................... 20

6-2.

Block Diagram  – MAIN Section – ................................. 21

6-3.

Block Diagram
– PANEL, POWER SUPPLY Section – .......................... 22

6-4.

Printed Wiring Board  – CD Board – .............................. 24

6-5.

Schematic Diagram  – CD Board – ................................. 25

6-6.

Printed Wiring Board
– MAIN Board (Component Side) – ............................... 26

6-7.

Printed Wiring Board
– MAIN Board (Conductor Side) – ................................. 27

6-8.

Schematic Diagram  – MAIN Board (1/2) – ................... 28

6-9.

Schematic Diagram  – MAIN Board (2/2) – ................... 29

6-10. Printed Wiring Boards  – REGULATOR Section – ........ 30
6-11. Schematic Diagram  – REGULATOR Section – ............. 31
6-12. Printed Wiring Boards  – PANEL, MOTOR Section – ... 32
6-13. Schematic Diagram  – PANEL, MOTOR Section – ........ 33
6-14. Printed Wiring Boards

– AMP, POWER SUPPLY Section (CMT-A50 only) – .. 34

6-15. Schematic Diagram

– AMP, POWER SUPPLY Section (CMT-A50 only) – .. 35

6-16. Printed Wiring Boards

– AMP Section (CMT-A70 only) – ................................. 36

6-17. Schematic Diagram

– AMP Section (CMT-A70 only) – ................................. 37

6-18. Printed Wiring Board

– POWER SUPPLY Section (CMT-A70 only) – ............ 38

6-19. Schematic Diagram

– POWER SUPPLY Section (CMT-A70 only) – ............ 39

7-1.

Overall Section ................................................................ 50

7-2.

Front Panel Section ......................................................... 51

7-3.

Top Case Section ............................................................. 52

7-4.

CD Mechanism Deck Section (FLM-A50) ..................... 53

7-5.

Optical Pick-up Section (KSM-213CCP) ........................ 54

7-6.

Optical Pick-up Section (KSM-213RCP) ........................ 55

7-7.

Speaker (Left) Section (A50) .......................................... 56

7-8.

Speaker (Right) Section (A50) ........................................ 57

7-9.

Speaker (Left) Section (A70) .......................................... 58

7-10. Speaker (Right) Section (A70) ........................................ 59

................................ 60

4

Power requirements
indication

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.

•

Model

Destination

Power Requirements

Indication

CMT-A50

AEP, UK, Italian,

AC: 230V-50Hz 50W

East European

and Russian models

Korean model

AC: 220V-60Hz 50W

CMT-A70

US and Canadian model

AC: 120V 60Hz 100W

AEP, UK, Italian,

East European, Russian

AC: 230V-50Hz 100W

and Australian models

1

Using a flat-tip screwdriver of the diameter 
less than 4 mm, rotate the gear in the arrow 
direction.

2

Pull-out the CD tray.