Sony TA-FB720R / TA-FB820R Service Manual ▷ View online
– 4 –
SECTION 2
ELECTRICAL ADJUSTMENT
Bias Adjustment
NOTE:
NOTE:
1. Perform the adjustment after the unit has warmed up sufficiently.
2. Perform the bias adjustment if the power transistor has been
2. Perform the bias adjustment if the power transistor has been
replaced.
Procedure:
1. Rotate fully the bias adjusting semi-fixed resistors (RV500,
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.
3. Set the slide regulator to 0V, and press the U 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
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 10 ± 0.1 mV.
7. Return the slidack to 0 V, and press the U button (OFF) on the
set.
Adjustment Location :
[MAIN BOARD] – COMPONENT SIDE –
1 pin
3 pin
–
–
+
+
CN500 (L-CH)
CN600(R-CH)
+
CN600 (R-CH)
1
3
3
CN500 (L-CH)
1
3
3
RV600
Bias (R-CH)
Bias (R-CH)
RV500
Bias (L-CH)
Bias (L-CH)
DIGITAL
VOLTMETER
VOLTMETER
DIGITAL
VOLTMETER
VOLTMETER
+
– 5 –
– 6 –
SECTION 3
DIAGRAMS
3-1. CIRCUIT BOARDS LOCATION
THIS NOTE IS COMMON FOR PRINTED WIRING
BOARDS AND SCHEMATIC DIAGRAMS.
(In addition to this, the necessary note is printed
in each block.)
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
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
and tantalums.
• All resistors are in
Ω
and
1
/
4
W or less unless otherwise
specified.
•
¢
: internal component.
•
2
: nonflammable resistor.
•
5
: fusible resistor.
•
C
: panel designation.
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.
•
U
: B+ Line.
•
V
: B– Line.
•
H
: adjustment for repair.
• Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
no mark : POWER ON
no mark : POWER ON
• Voltages are taken with a VOM (Input impedance 10 M
Ω
).
Voltage variations may be noted due to normal produc-
tion tolerances.
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
tion tolerances.
• Circled numbers refer to waveforms.
• Signal path.
• Signal path.
F
: TUNER
WAVEFORM
1
IC902
1
XOUT
Note: The components identified by mark
!
or dotted line
with mark
!
are critical for safety.
Replace only with part number specified.
• Indication of transistor
C
These are omitted
E
B
4MHz
3.8Vp-p
PANEL board
INPUT board
MAIN board
SP-TM board
PHONO board
PS board
OUTLET board
VOL board
SIRCS board
SIRCS SUB board
HP board
SP-SW board
– 7 –
– 8 –
TA-FB720R/FB820R
3-2. SCHEMATIC DIAGRAM – INPUT SECTION –
• See page 23 for IC Block Diagrams.
(Page 15)
(Page 15)
(Page 12)
– 9 –
– 10 –
TA-FB720R/FB820R
3-3. PRINTED WIRING BOARD – INPUT SECTION –
• See page 5 for Circuit Boards Location.
Ref. No.
Location
• Semiconductor
Location
D101
B-7
D102
B-8
D133
C-9
D140
B-4
D240
B-4
IC101
B-9
Q101
C-7
Q102
C-7
Q103
C-8
Q140
C-4
Q240
B-4
(Page 18)
(Page 17)
(Page 13)