Sony SRF-M73 Service Manual ▷ View online
– 4 –
CABINET (FRONT)/(REAR) ASSY
KEY BOARD
·
This set can be disassembled in the order shown below.
SECTION 3
DISASSEMBLY
Set
Key Board
Main Board
Knob (A)
Cabinet (Rear) Assy
Cabinet (Front) Assy
2
three screws
(B1.7
(B1.7
×
8)
2
two screws
(B1.7
(B1.7
×
8)
1
Remove the battery case lid
of the arrow.
of the arrow.
3
cabinet (front) assy
4
cabinet (rear) assy
1
three claws
2
Open the key board
to direction of the arrow.
to direction of the arrow.
1
four claws
Note:
Follow the disassembly procedure in the numerical order given.
– 5 –
MAIN BOARD
KNOB (A)
Note: Check that two switch (S1,
S2) is latched with two
adaptors when carrying
out installation.
adaptors when carrying
out installation.
2
screw
(B1.7
(B1.7
×
8)
1
Remove two solders.
3
knob (vol)
4
two claws
S1
S2
5
main board
2
two knobs (A)
1
claw
1
claw
3
two adaptors
– 6 –
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter
T1
450 kHz
AM VCO VOLTAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L4
530 kHz (531 kHz)
3 ± 0.1V
Confirmation
1710 kHz (1602 kHz)
9 ± 1V (8.5 ± 1V)
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L1
580 kHz (621 kHz)
CT1
1,490 kHz (1,395 kHz)
FM VCO VOLTAGE CONFIRMATION
Frequency Display
Reading on Digital Voltmeter
87.5 MHz
3 ± 0.3V
108 MHz
Less than 11 ± 1V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L2
87.5 MHz
CT2
108 MHz
( ): Panama model
SECTION 4
ELECTRICAL ADJUSTMENTS
0 dB = 1 µV
[AM]
Setting:
Band switch: AM
Band switch: AM
[FM]
Setting:
Band switch: FM
Band switch: FM
• Repeat the procedures in each adjustment several times, and the
tracking adjustments should be finally done by the trimmer ca-
pacitors.
pacitors.
Adjustment Location: Main Board (See page 7)
FM RF signal
generator
22.5 kHz frequency
deviation by 400 Hz
signal
Output level: as low as possible
deviation by 400 Hz
signal
Output level: as low as possible
+
–
–
level meter
2
jack (J1)
set
MAIN board
TP (FM IN)
TP (FM IN)
32
Ω
0.01
µ
F
+
–
–
digital voltmeter
MAIN board
TP (VT)
FM Free-Run Adjustment
Setting:
Procedure:
1. Connect the frequency counter to TP (MPX) as shown the fig-
1. Connect the frequency counter to TP (MPX) as shown the fig-
ure below.
2. Tune the set to 98 MHz.
3. Adjust RT1 for 76 kHz reading on the frequency counter.
3. Adjust RT1 for 76 kHz reading on the frequency counter.
Specification: 75.8 kHz to 76.2 kHz
Adjustment Location: MAIN board (See page 7)
0.01
µ
F
MAIN board
TP (FM IN)
TP (FM IN)
set
FM RF signal
generator
generator
Carrier frequency : 98 MHz
Modulation
Modulation
: no modultion
Output level
: 0.1 V (100 dB)
+
–
–
MAIN board
TP (MPX)
+
1
µ
F
frequency
counter
counter
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
Output level: as low as possible
modulation by
400 Hz signal
Output level: as low as possible
Put the lead-wire
antenna close to
the set.
antenna close to
the set.
+
–
–
level meter
set
32
Ω
2
jack (J1)
SRF-M73
– 7 –
– 8 –
– 9 –
– MAIN BOARD (Component Side) –
Adjustment Location:
– MAIN BOARD (Conductor Side) –
L4
AM VCO Voltage Adjustment
AM VCO Voltage Adjustment
RT1
FM Free-Run Adjustment
FM Free-Run Adjustment
CT1
AM Tracking Adjustment
AM Tracking Adjustment
L1
AM Tracking Adjustment
AM Tracking Adjustment
T1
AM IF Adjustment
AM IF Adjustment
FM Tracking Adjustment
CT2
L2
L2
TP
(MPX)
TP
(FM IN)
TP
(VT)
J1
SECTION 5
DIAGRAMS
5-1.
BLOCK DIAGRAM
18
20
16
13
19
24
22
FM
FRONT-END
FM IF AMP/
DISCRI
DECODER
AMP
SWITCH
BASS
BOOST
CONTROL
POWER
AMP
DET
REGULATOR
1/2
COUNTER
1/2
COUNTER
AM IF AMP/
DET
TUNING
INDICATOR
PD1
VCO
PD2
AM
FRONT-END
14
FM RF
IN
IN
FM/AM
MIX OUT
CF3: US
CF4, 5: PANAMA
10.7MHz
CF1
10.7MHz
BASS BOOST AMP
IC2
SYSTEM CONTROLLER,
LIQUID CRYSTAL DISPLAY DRIVER,
KEY CONTROL
IC101
EEPROM
IC105
CF2
450kHz
FM
RF
RF
26
FM DISCRI
FM
IF IN
IF IN
6
7
21
5
1
2
14
13
L-CH
OUT
R-CH
OUT
4
27
29
1
2
3
ST IND
AM
IF IN
IF IN
PILOT DET
LPF2
12
TUNE IND
9
AFC1/AGC
15
BAND
SELECT
PILOT DET
LPF1
PLL
LPF1
PLL
LPF2
VCO
AM OSC
FM OSC
AM RF
IN
IN
FM/AM FRONT-END,
FM/AM DET, MPX
IC1
RT1
FM FREE-RUN
L4
AM VCO VOLTAGE
CT2, L2
FM TRACKING
S1
FM SENS
T1
AM IF
CT1, L1
AM TRACKING
L.P.F.
B.P.F.
BPF1
FM VCO
BUFFER
BUFFER
Q1
FM/AM BAND
SELECT SWITCH
Q3
COMPARATOR
IC4 (1/2)
LIQUID CRYSTAL DISPLAY
LCD101
VOLTAGE
DETECT
IC102
B+ SWITCH
Q104
DC/DC
CONVERTER
Q103, T101
B+ SWITCH
Q6
AM IF
BUFFER
Q4, 5
LOW-PASS
FILTER
Q101
• SIGNAL PATH
: FM
: AM
05
POWER
AMP
MUTE
CONTROL
RIPPLE FILTER
Q2
KEY MATRIX
S101 – 111, 113 – 116
KS0 – KS3
KR0 – KR3
X101
75kHz
SYSTEM CONTROLLER (IC101),
EEPROM (IC105) B+
FM/AM TUNER (IC1),
HEADPHONE AMP (IC3) B+
BASS BOOST AMP (IC2) B+
PLL LOW-PASS FILTER CIRCUIT B+
AM IF AMP CIRCUIT B+
D105
–1
–2
IN1
IN2
HEADPHONE AMP
IC3
2
4
IN1
IN2
OUT1
OUT2
9
7
OUT1
OUT2
LP
GAIN
B+
VREF
5
6
7
COMPARATOR
IC4 (2/2)
3
2
1
B+
CT1
D1-1
L1
AM FERRITE-ROD
ANTENNA
L2
FM RF
(PANAMA)
POWER
XOUT
XIN
IF ON
CE
DET
IN
MT/SW
REG
VCC
AM IF IN
EO
VCOL
VCOH
BAND
CMP IN
24
D
ATA
15
CK
14
2
1
CS
SK
3
DI
4
DO
CS
16
25
2 1
50
6
12
10
53
MUTE
5
BEEP
52
3
17
21
20
19
DX
LOCAL
S2
MEGA
BASS
ON
OFF
D1-2
D3
CT2
D2
L4
AM OSC
L3
FM OSC
RV1
VOL
J1
(HEADPHONE)
2
+
DRY BATTERY
SIZE “AAA”
(IEC DESIGNATION R03)
2PCS. 3V
10 – 13
6 – 9
COM0 – COM3
31 – 34
SEG0 – SEG14
35 – 49