Sony TAFB-940-R Service manual

TA-FB940R

SERVICE MANUAL

Photo: BLACK model

SPECIFICATIONS

Amplifier section

DIN power output

Except UK, Singapore, Malaysia:

120 W + 120 W (4 Ω at 1 kHz)
80 W + 80 W (8 Ω at 1 kHz)

UK, Singapore, Malaysia model:

95 W + 95 W (4 Ω at 1 kHz)
60 W + 60 W (8 Ω at 1 kHz)

Total harmonic distortion

Less than 0.008% (at 10 W output 1 kHz)

Frequency response

PHONO (20 Hz - 20 kHz): RIAA equalization curve
±0.5 dB
TUNER, SACD/CD, AUX, TAPE1/DAT, TAPE2/MD:
7 Hz - 300 kHz

S/N (network A)

PHONO
94 dB
TUNER, SACD/CD, AUX, TAPE1/DAT, TAPE2/MD:
105 dB

Output voltage/impedance

REC OUT 1, 2: 150 mV, 1 kΩ
PHONES: 10 mW (at 8 Ω)

+0–3

dB

AEP Model

UK Model

E Model

Australian Model

General

System

Power amplifier: Pure-complementary SEPP OCL
power amplifier with all stages directly coupled
Preamplifier: Low-noise, equalizer amplifier

Power requirements

230 V AC, 50/60 Hz

Power consumption

210 W

Dimensions (approx.) (w/h/d)

430 × 150 × 420 mm
incl. projecting parts and controls

Mass (approx.)

10.3 kg

Supplied accessories

• Remote commander (remote) (1) RM-S336

• Sony batteries R6 (size-AA) (2)

Design and specifications are subject to change without

notice.

Speakers impedance

4 - 16 Ω, 8 - 16 Ω (SPEAKERS A+B)

Damping factor

500 (8 Ω, 1 kHz)

INTEGRATED STEREO AMPLIFIER

1

TABLE OF CONTENTS

1. GENERAL .......................................................................... 3

2. ELECTRICAL ADJUSTMENT ..................................... 4

3. DIAGRAMS

3-1. Circuit Boards Location ........................................................ 5

3-2. Schematic Diagram – Input Section – .................................. 6

3-3. Printed Wiring Board – Input Section – ................................ 7

3-4. Schematic Diagram – Main Section – .................................. 8

3-5. Printed Wiring Board – Main Section – ................................ 9

3-6. Schematic Diagram – Panel Section – ................................ 10

3-7. Printed Wiring Board – Panel Section – ............................. 11

3-8. Schematic Diagram – Power Section – ............................... 12

3-9. Printed Wiring Board – Power Section – ............................ 13

3-10. IC Block Diagrams ............................................................ 14

3-11. IC Pin Function ................................................................. 14

4. EXPLODED VIEW

4-1. Case Section ........................................................................ 15

4-2. Front Panel Section ............................................................. 16

4-3. Chassis Section ................................................................... 17

5. ELECTRICAL PARTS LIST ........................................ 18

SAFETY-RELATED COMPONENT WARNING !!

COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED LINE
WITH MARK 0 ON THE SCHEMATIC DIAGRAMS AND IN

THE PARTS LIST ARE CRITICAL TO SAFE OPERATION.

REPLACE THESE COMPONENTS WITH SONY PARTS

WHOSE PART NUMBERS APPEAR AS SHOWN IN THIS

MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.

2

Front Panel Descriptions

2

22

21

20

SECTION 1

GENERAL

78

3

4

65110

1819

17

16

9

15

14

11

12

13

1 PROTECTION indicator
2 POWER button
3 Remote sensor
4 EON LINK indicator
5 TAPE 1/DAT indicator
6 TAPE 2/MD indicator
7 AUX indicator
8 SACD/CD indicator

9 TUNER indicator
10 PHONO indicator
11 INPUT SELECTOR knob

Rear Panel Descriptions

PHONO

SIGNAL

IN

IN

TUNER

GND

U

B

L

A

REC OUT IN

TAPE1/DAT

R

REC OUT IN

IN

IN

SACD/

TAPE2/MD

AUX

CD

L

R

L

R

3 51

IMPEDANCE USE 4–16Ω

A+B USE 8–16Ω

BI WIRE USE 4–16Ω

SPEAKERS

++––

R

++––

RL

L

12 VOLUME knob
13 SOURCE DIRECT button and indicator
14 TAPE MONITOR knob
15 SUBSONIC button
16 LOUDNESS button
17 BALANCE knob
18 TREBLE knob
19 BASS knob
20 SPEAKERS knob
21 PHONE jack
22 EON LINK button

42

AC OUTLET

SWITCHED 100W MAX

EON CONTROL

IN

This section is extracted from
instruction manual.

1 PHONO
2 U (SIGNAL GND)
3 SPEAKERS A/B

0qa 9 8 7 6

4 EON CONTROL IN
5 AC OUTLET

(Except UK, Singapore, Malaysia)

6 Mains lead
7 TAPE1/DAT
8 TAPE2/MD

9 AUX
0 SACD/CD
qa TUNER

3

SECTION 2

R

ELECTRICAL ADJUSTMENT

Bias Adjustment
NOTE:

1. Perform the adjustment after the unit has warmed up sufficiently.

2. Perform the bias adjustment if the power transistor has been
replaced.

Procedure:

1. Rotate fully the bias adjusting semi-fixed resistors (RV500,
RV600) to the MIN position (counterclockwise).

2. Connect a digital voltmeter to the CN500 and CN600.

1 pin 2 pin

CN500 (L-CH)

CN600(R-CH)

+

+

3. Set the slide regulator to 0V, and press the POWER button
(ON) on the set.

4. Raise gradually the slide regulator voltage up to the rated voltage.

5. At this time, confirm that the SP relay is turned on (it will click).

6. Adjust the RV500 and RV600 so that a reading of digital
voltmeter is 7 ± 1 mV.

7. Return the slidack to 0 V, and press the POWER button (OFF)
on the set.

–

–

Adjustment Location :

[MAIN BOARD] – COMPONENT SIDE –

RV500
Bias (L-CH)

RV600
Bias (R-CH)

CN500
(L-CH)

12

21

CN600
(R-CH)

+

DIGITAL
VOLTMETER

+

DIGITAL
VOLTMETE

4

SECTION 3

DIAGRAMS

TA-FB940R

3-1. CIRCUIT BOARDS LOCATION

SIRCS board

SIRCS SUB board

HP board

TONE board

PANEL board

S-D LED board

PS board

OUTLET board
(EXCEPT UK, SP, MY)

SP-TM board

MAIN board

VOL board

PHONO board

INPUT board

THIS NOTE IS COMMON FOR PRINTED WIRING
BOARDS AND SCHEMATIC DIAGRAMS.
(In addition to this, the necessary note is printed
in each block.)

For schematic diagrams.

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/
specified.

f

•

• 2 : nonflammable resistor.

• 5 : fusible resistor.

• C : panel designation.

Note: The components identified by mark 0 or dotted line

• U : B+ Line.

• V : B– Line.

• H : adjustment for repair.

• Voltages and waveforms are dc with respect to ground

• Voltages are taken with a VOM (Input impedance 10 MΩ).

• Waveforms are taken with a oscilloscope.

• Circled numbers refer to waveforms.

• Signal path.

• Abbreviation

: internal component.

with mark 0 are critical for safety.
Replace only with part number specified.

under no-signal (detuned) conditions.
no mark : POWER ON

Voltage variations may be noted due to normal produc­tion tolerances.

Voltage variations may be noted due to normal produc­tion tolerances.

F : TUNER

G : German model.
EE : East European model.
AUS : Australian model.
SP : Singapore model.
MY : Malaysia model.

4

W or less unless otherwise

WAVEFORM

1

3.8Vp-p

4MHz

IC902 1 XOUT

For printed wiring boards.

Note:

• X : parts extracted from the component side.

• Y : parts extracted from the conductor side.

• b : Pattern from the side which enables seeing.

• Indication of transistor

C

EB

These are omitted

55

TA-FB940R

3-2. SCHEMATIC DIAGRAM – INPUT SECTION –

C101 – 105, 201 – 205

*

EXCEPT UK, SP, MY

*

*

*

SACD/CD

*

470
16V

470
16V

2SD2525

22

25V

22

25V

2SB1640

63V

63V

EXCEPT UK, SP, MY

R140

0

82

1W

10

10

R240

0

82

1W

+15V

–15V

+B
GND

–B

(Page 8)

JW11

UK, SP, MY
MODEL

16V

*

*

(Page 10)

*

*

*

*

UK, SP, MY
MODEL

JW12

EXCEPT UK, SP, MY

16V

(Page 10)

66

3-3. PRINTED WIRING BOARD – INPUT SECTION – • See page 5 for Circuit Boards Location.

TA-FB940R

• Semiconductor
Location
(INPUT Board)

Ref. No. Location

D100 D-5
D101 D-4
D102 D-4
D103 C-4
D104 B-4
D105 A-4
D106 A-4
D107 D-5
D108 C-7
D140 C-9
D240 C-9

Q100 C-6
Q101 C-6
Q102 C-6
Q103 C-7
Q104 C-7
Q105 C-7
Q140 C-9
Q240 D-9

• Semiconductor
Location
(PHONO Board)

Ref. No. Location

D170 B-1

IC150 A-2

Q150 A-3
Q151 A-3
Q250 B-3
Q251 B-3

C101 – 105, 201 – 205

*

EXCEPT UK, SP, MY

*

*

*

*

*

*

*

*

*

*

77

TA-FB940R

3-4. SCHEMATIC DIAGRAM – MAIN SECTION – • See page 14 for IC Block Diagrams.

C511, 512, 611, 612

*

R533, 534, 633, 634

*

EXCEPT UK, SP, MY

*

*

*

*

*

*

*

88