Sony TA-F448EB Service Manual ▷ View online
– 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)
(case 3 TP2)
3
two screws
(case 3 TP2)
(case 3 TP2)
3
two screws
(case 3 TP2)
(case 3 TP2)
4
case ass'y
1
connector
(CN201)
(CN201)
2
connector
(CN701)
(CN701)
3
connector
(CN405)
(CN405)
4
connector
(CN809)
(CN809)
5
connector
(CN104)
(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)
(CN301, 302)
2
connector
(CN104)
(CN104)
3
three screws
(3
(3
×
8)
4
Remove the INPUT board
to direction of the arrow
to direction of the arrow
A
.
5
two connectors
(CN16, 103)
(CN16, 103)
!¡
four screws (H)
6
two connectors
(CN401, 402)
(CN401, 402)
!º
screw
(3
(3
×
8)
8
connector
(CN405)
(CN405)
7
two connectors
(CN403A, 404A)
(CN403A, 404A)
9
Break the soldering of
three power transformer
leads.
three power transformer
leads.
!º
three screws
(3
(3
×
8)
!¢
heat sink
!£
two screws
(transistor)
(transistor)
!™
MAIN (B) board
A
!¢
heat sink
!£
two screws
(transistor)
(transistor)
!¡
four screws (H)
MAIN (A) BOARD
1
connector
(CN201)
(CN201)
2
five screws
3
MAIN (A) board
– 7 –
+
–
BIAS ADJUSTMENT
Adjustment Procedure:
1. Rotate fully the bias adjusting semi-fixed resistors (RV301 (L-
1. Rotate fully the bias adjusting semi-fixed resistors (RV301 (L-
CH), RV351 (R-CH)) to the minimum position (counterclock-
wise).
wise).
2. Connect a digital voltmeter to the CN406 (L-CH) and CN407
(R-CH).
3. Set the slidack to 0 V AC, 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
1
pin
3
CN406 (L-CH)
–
+
CN407 (R-CH)
+
–
Connection and Adjustment Location:
[MAIN (A) BOARD]
– Component side –
– Component side –
[MAIN (B) BOARD] – Component side –
digital voltmeter
C372 C322
RV351
(R-CH)
(R-CH)
RV301
(L-CH)
(L-CH)
BIAS
Adjustment
Adjustment
C459
C409
CN407
3
1
SECTION 3
ELECTRICAL ADJUSTMENT
CN406
1
3
– 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
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