CMT-SP55MD, CMT-SP55TC, ST-SP55 - Sony Audio Service Manual (repair manual)

1

AEP Model

UK Model

E Model

FM stereo, FM/AM superheterodyne tuner
Input
AUX IN (phono jacks):

voltage 250 mV, impedance
47 kilohms

Output
AUX OUT (phono jacks): voltage 250 mV, impedance

1 kilohm

Tuning range

87.5 – 108.0 MHz
(50 kHz step)

Aerial

FM lead aerial

Aerial terminals

300 ohms unbalanced

Intermediate frequency

10.7 MHz

Tuning range
European model:

531 – 1,602 kHz
(with the interval set at 9 kHz)

Other models:

531 – 1,602 kHz
(with the interval set at 9 kHz)
530 – 1,710 kHz
(with the interval set at 10 kHz)

Aerial

AM loop aerial
External aerial terminals

Intermediate frequency

450 kHz

Dimensions (w/h/d) incl. projecting parts and controls

Approx. 202 

× 75 × 291 mm

Mass

Approx. 1.3 kg

Design and specifications are subject to change
without notice.

ST-SP55 is the tuner section
in CMT-SP55MD or CMT-SP55TC.

2

0

0

3

.......................................................................... 3

3-1. Circuit Boards Location ........................................................ 4
3-2. Block Diagram ...................................................................... 5
3-3. Schematic Diagram – Main Section – .................................. 6
3-4. Printed Wiring Board – Main Section – ................................ 7
3-5. Schematic Diagram – Panel Section – .................................. 8
3-6. Printed Wiring Board – Panel Section – ................................ 9
3-7. IC Pin Functions .................................................................. 10
3-8. IC Block Diagram ............................................................... 11

4-1. Case and Front Panel .......................................................... 12

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

3

1

      (Remote sensor)

2

Display window

3

TUNING +/– button

4

TUNER/BAND button

5

TUNING MODE button

6

DISPLAY button

1

6

5

4

2

3

• This unit displays CD text.

Text is displayed for the first 50 track only and will not be displayed from the 51st track onwards. Do not suspect a fault in this case.
In some cases, some special characters will not be displayed and may be replaced by other characters. Do not suspect a fault in this case.

• The cold reset clears all data including preset data stored in the RAM to initial conditions. Execute this mode when returning  the set to the

customer.

Procedure :
1. When the power ON, press the  ?/1  button (TA) while pressing the  TUNING MODE  button (ST) and  ML buttons (CDP) together.
2. “COLD RESET” is displayed on the fluorescent indicator tube and reset is executed.

• This mode reset the preset data kept in the memory. The hot reset mode functions same as if the power cord is plugged in and out.

Procedure :
1. When the power ON, press the  ?/1  button (TA) while pressing the  TUNING MODE  button (ST) and lm buttons (CDP) together.
2. Turn off the unit and reset is executed.

Procedure :
1. When the power ON, press the  ?/1  button (TA) while pressing the  TUNING MODE  button (ST) and PLAY MODE  buttons (CDP)

together.

2. LCD are all turned on.
3. Press  TUNING MODE  button (ST) to enter the model destination indecation mode. “SP55    CE2” or “SP55    ASIA2” appears.
4.

Every pressing of  TUNING MODE  button (ST) changes the display in the following order.
MC Version 

t CD Version t ST Version t TC Version t TA Version t TM Version t model destination display.

5.

Press  DISPLAY  button (ST) and the date appears as “ 00615a ”
Every pressing of  DISPLAY  button (ST) changes the display in the Version display and model destination display.

6. Press  TUNER/BAND  button (ST) to enter the key check mode.
7. In the key check mode, the fluorescent indicator tube displays “Key 0 Vol 0”. Each time a button is pressed, “Key” value increases.

However, once a button is pressed, it is no longer taken into account.
“Vol” Value increases like “1, 2, 3 ...” if rotating  VOLUME  knob (TA) in the clockwise direction, or decreases like “0, 9, 8 ...” if rotating
in the counterclockwise diretion.

8. To exit from this mode, disconnect the power cord.

This unit cannot be repaired by itself.
When repairing, connect the whole system except for the speaker.

4

Note:
• All capacitors are in µF unless otherwise noted.  pF: µµF

50 WV or less are not indicated except for electrolytics
and tantalums.

• All resistors are in 

Ω

 and 

1

/

4

 

W or less unless otherwise

specified.

•

f

: internal component.

•

C

: panel designation.

• X

: parts extracted from the component side.

• Y

: parts extracted from the conductor side.

•

a

: Through hole.

• b

: Pattern from the side which enables seeing.

(The other layers' patterns are not indicated.)

•

U

: B+ Line.

•

V

: B– Line.

•

H

: adjustment for repair.

• no mark : FM

∗

: Can not be measured.

• Voltages are taken with a VOM (Input impedance 10 M

Ω

).

Voltage variations may be noted due to normal produc-
tion tolerances.

• Waveforms are taken with a oscilloscope.

Voltage variations may be noted due to normal produc-
tion tolerances.

• Circled numbers refer to waveforms.
• Signal path.

F

: FM

J

: CD

d

: TAPE

G

: REC (TAPE/MD)

j

: MD

• Abbreviation

MY

: Malaysia model.

SP

: Singapore model.

HK

: Hong Kong model.

KR

: Korea model.

AED

: North European model.

Note:
The components identified by mark 

0

 or

dotted line with mark 

0

 are critical for

safety.
Replace only with part number specified.

qa

 XCOUT

qd

 XOUT

30.5

µ

sec

100nsec

2.7Vp-p

4.6Vp-p