Sony TA-F448EB User manual

MICROFILM
TA-F448EB
INTEGRATED STEREO AMPLIFIER
+11
–3
SERVICE MANUAL
AEP Model
UK Model
SPECIFICATIONS
Amplifier section
DIN power output
85 W + 85 W (4 ohms at 1 kHz)
55 W + 55 W (8 ohms at 1 kHz)
Total harmonic distortion
Less than 0.008% (at 10 W output)
Frequency response
PHONO (20 Hz – 20 kHz): RIAA equalization curve ±0.5 dB
TUNER, CD, AUX, TAPE1/DAT, TAPE2/MD: 7 Hz – 100 kHz dB
S/N (network A)
PHONO: 94 dB
TUNER, CD, AUX, TAPE1/DAT, TAPE2/MD: 105 dB
Output voltage/impedance
RECOUT: 150 mV, 1 kilohm
PHONES: 10 mW (at 8 ohms)
Speakers impedance
4 – 16 ohms, 8 – 16 ohms (SPEAKERS A + B)
Damping factor
100 (8 ohms, 1 kHz)
General
System
Poweramplifier:Pure-complementarySEPP OCLpower amplifierwith
all stages directly coupled
Preamplifier: Low-noise, equalizer amplifier
Power requirements
230 V AC, 50/60 Hz
Power consumption
180 W
Dimensions (approx.) (w/h/d)
430 ×135 ×365 mm
incl. projecting parts and controls
Mass (approx.)
6.8 kg
Design and specifications are subject to change without notice.

– 2 –
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK !OR DOTTED
LINE WITH MARK !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 PUB-
LISHED BY SONY.
TABLE OF CONTENTS
1. GENERAL ................................................................... 3
2. DISASSEMBLY.......................................................... 5
3. ELECTRICAL ADJUSTMENTS ......................... 7
4. DIAGRAMS ................................................................. 8
4-1. Printed Wiring Boards ..................................................... 10
4-2. Schematic Diagram ......................................................... 15
5. EXPLODEDVIEWS ................................................. 19
6. ELECTRICAL PARTS LIST................................ 22

– 3 –
SECTION 1
GENERAL This section is extracted
from instruction manual.

– 4 –

– 5 –
Note: Follow the disassembly procedure in the numerical order given.
CASE ASS'Y
SECTION 2
DISASSEMBLY
FRONT PANEL SECTION
1 two screws
(case 3 TP2)
2 three screws
(case 3 TP2)
3 two screws
(case 3 TP2)
3 two screws
(case 3 TP2)
4 case ass'y
1 connector
(CN201)
2 connector
(CN701)
3 connector
(CN405)
4 connector
(CN809)
5 connector
(CN104)
6 five screws
(3
× 8)
7 two screws
(3
× 8)
8 screw
(BVTP2.6
× 8)
8 screw
(BVTP3
× 8)
9 front panel section

– 6 –
INPUT BAORD, MAIN (B) BAORD
1 two connectors
(CN301, 302)
2 connector
(CN104)
3 three screws
(3
× 8)
4 Remove the INPUT board
to direction of the arrow
A .
5 two connectors
(CN16, 103)
!¡ four screws (H)
6 two connectors
(CN401, 402)
!º screw
(3
× 8)
8 connector
(CN405)
7 two connectors
(CN403A, 404A)
9 Break the soldering of
three power transformer
leads.
!º three screws
(3
× 8)
!¢ heat sink
!£ two screws
(transistor)
!™ MAIN (B) board
A
!¢
heat sink
!£ two screws
(transistor)
!¡ four screws (H)
MAIN (A) BOARD
1 connector
(CN201)
2 five screws
3 MAIN (A) board

– 7 –
+
–
BIAS ADJUSTMENT
Adjustment Procedure:
1. Rotate fully the bias adjusting semi-fixed resistors (RV301 (L-
CH), RV351 (R-CH)) to the minimum position (counterclock-
wise).
2. Connect a digital voltmeter to the CN406 (L-CH) and CN407
(R-CH).
3. Set the slidack to 0VAC, and press the POWER button (ON)
on the set.
4. Raise gradually the slidack voltage up to the rated voltage (230
V AC).
5. At this time, confirm that the speaker relay is turned on (it will
click).
6. Adjust the RV301 (L-CH) and RV351 (R-CH) so that a reading
of digital voltmeter is from 10 mV to 20 mV.
7. Return the slidack to 0 V AC, and press the POWER button
(OFF) on the set.
pin 1pin 3
CN406 (L-CH) – +
CN407 (R-CH) + –
Connection andAdjustment Location:
[MAIN (A) BOARD]
– Component side –
[MAIN (B) BOARD] – Component side –
digital voltmeter
C372 C322
RV351
(R-CH)
RV301
(L-CH)
BIAS
Adjustment
C459 C409
CN407
31
SECTION 3
ELECTRICAL ADJUSTMENT
CN406
13

– 8 –
• IC Block Diagram
IC401 µPC1237HA
SECTION 4
DIAGRAMS
1 2 3 4 5 6 7 8
OVER LOAD DET
F/F
OFFSET DET
LATCH/
AUTORESET
V
CC ON
MUTE
AC OFF
DET
V
CC

– 9 –
• Circuit Boards Location
MAIN (B) board SP-TM board
INPUT board
MAIN (A) board
VOL board
LED-F board
SW-F board
SP-SW board
HP board
LED-P board