Sony SRF-M37 Service Manual ▷ View online
5
SRF-M37
SECTION 3
ADJUSTMENTS
Setting:
BAND switch: AM
Connection:
BAND switch: AM
Connection:
For AM frequency coverage adjustment and FM frequency coverage check.
AM Section
digital
voltmeter
voltmeter
TP10 (VT)
Connection:
AM RF signal
generator
generator
30% amplitude modulation by
400 Hz signal.
Output level: as low as possible
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
headphone jack (
i
)
16
Ω
+
–
–
FM Section
FM RF signal
generator
generator
22.5 kHz frequency deviation
by 400 Hz signal.
Output level: as low as possible
by 400 Hz signal.
Output level: as low as possible
0.01
µ
F
TP12 (ANT)
Setting:
BAND switch:
BAND switch:
FM
FM SENS switch: DX
Connection:
Adjustment Location
TP10
(VT)
(VT)
TP12
(ANT)
(ANT)
MAIN BOARD
MAIN BOARD
IC2
IC1
(Conductor side)
CT2
L3
AM TRACKING
Adjustment
Adjustment
L4
AM FREQUENCY
COVERAGE Adjustment
AM FREQUENCY
COVERAGE Adjustment
(Component side)
CT1
L1
FM TRACKING
Adjustment
Adjustment
AM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a reading on digital voltmeter.
L4
530 kHz
1.3V
± 0.1V
Confirm
1,710 kHz
8.1V
± 0.3V
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
CT2
1480 kHz
L3
590 kHz
FM FREQUENCY COVERAGE CHECK
Check a reading on digital voltmeter.
Confirm
87.5 MHz
6.9V
± 0.3V
Confirm
108.0 MHz
12.1V
± 0.3V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
CT1
108.0 MHz
L1
87.5 MHz
6
SRF-M37
SECTION 4
DIAGRAMS
1
IC101
tg
XOUT
1.1 Vp-p
13
µ
s
TIME/div : 4
µ
s/DIV
VOLT/div : 500 mV/DIV
2
Q106 collector
1.8 Vp-p
262 ns
TIME/div : 100 ns/DIV
VOLT/div : 500 mV/DIV
VOLT/div : 500 mV/DIV
Note on Schematic Diagram:
• 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.
•
C
: panel designation.
•
A
: B+ Line.
•
H
: adjustment for repair.
• Power voltage is dc 1.5 V and fed with regulated dc power
supply from battery terminal.
• Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
no mark : FM
<
no mark : FM
<
> : AM
• 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.
F
: FM
f
: AM
• Waveform
Note on Printed Wiring Board:
• Y
: parts extracted from the conductor side.
•
b
: Pattern from the side which enables seeing.
•
: Carbon pattern.
Caution:
Pattern face side: Parts on the pattern face side seen from
(Side B)
Pattern face side: Parts on the pattern face side seen from
(Side B)
the pattern face are indicated.
Parts face side:
Parts on the parts face side seen from
(Side A)
the parts face are indicated.
• Indication of transistor
Q
C
These are omitted
E
B
7
7
SRF-M37
4-1.
Block Diagram
: FM
• Signal Path
: AM
23
L1
L3
FERRITE-ROD
ANTENNA
D1
D2
2
29
24
27
25
FM
MIX
FM RF IN
FM RF OUT
FM OSC
AM RF IN
AM OSC
FM
OSC
AM
MIX
AM
OSC
OSC
OUT
OUT
4
5
FM MIX
AM MIX
12
CF1
10.7MHz
CF2
450kHz
8
10
FM IF IN
AM IF IN
FM
MPX
FM/AM
BUFFER
FM
DET
AM
DET
13
DET
OUT
OUT
16
15
11
FRONT-END
IF AMP,DET,FM MPX
26
7
VCC
QUAD
RF VCC VCC
14
22
LPF1
MODE2
VCC
VCC
VCC
VCC
VCC
CT1
L2
D3
CT2
D4
L4
IC1
MPX
IN
IN
L1, CT1
FM
TRACKING
L3, CT2
AM
TRACKING
L4
AM
FREQUENCY
COVERAGE
Q5
Q3
RF
AMP
Q6
BUFFER
Q4
SWITCH
10.7MHz
CF3
AUDIO
POWER AMP
IC2
40
DO
Q1
RF
AMP
Q2
BPF1
B.P.F.
FM SENS
DX
LOCAL
OFF
ON
L.P.F
Q104,105
S1
IN 2
4
IN 1
2
VOL
RV1
REF
5
MUTE SW
10
OUT 2
LOUT
ROUT
7
OUT 1
9
J1
DC-DC
CONV
T101
Q106, 107
VCC
38
OSC IN
31
BAND2
21
MODE1
32
BAND1
50
ST/MONO
29
AM BAND
49
MUTE
28
BEEP
X OUT
55
LCD101
LIQUID CRYSTAL
DISPLAY
S102 - S112
KEY MATRIX
X IN
56
X101
75kHz
1
4
COM1
COM4
5
17
S1
S13
VOLTAGE
DETECT
2
1
VDET 35
IC102
HOLD
34
HOLD
S101
KR1
24
DIGITAL TUNING
SYSTEM CONTROL
IC101
KR2
25
KR3
26
KS1
21
KS0
20
KR0
23
KS2
22
DRY BATTRY
SIZE "AAA"
(IEC DESIGNATION R03)
1PC 1.5V
Q101, 102
Q103
VDD
D101
IC103
VCC
BATT
RESET
RESET 54
POWER ON 2 46
VCC
Q7, 8
POWER ON 1 52
8
8
SRF-M37
4-2.
Printed Wiring Boards
IC101
IC102
IC103
IC1
IC2
E
1
16
17
32
33
48
49
64
1
2
3
4
1
4
2
3
E
E
E
E
E
E
E
1-686-881-
11
(11)
E
E
E
1
5
6
10
E
E
E
S
1
5
10
15
16
20
25
30
RV1
MAIN BOARD
KEY BOARD
VOL
C55
C48
C30
C32
C53
C31
C54
C126
C109
C102
T101
JW102
1
5
15
10
17
LCD101
(LIQUID CR
YST
AL DISPLA
Y)
X101
S101
HOLD
OFF
ON
1-686-882-
11
(11)
JW101
S1
FM SENS
DX
LOCAL
L7
JW5
CF1
CF2
CF3
J1
TP12
(ANT)
JW4
JW3
L1
L4
TP10
(VT)
CT2
JW1
CT1
W1
W2
1
5
1
6
L3
AM FERRITE-ROD
ANTENNA
AM FERRITE-ROD
ANTENNA
W1
W2
1
5
1
6
DRY BATTERY
SIZE "AAA"
(IEC DESIGNATION R03)
1PC 1.5V
W3
LCD
SHIELD
BPF1
JW2
S103
4
S110
6
S109
3
S108
2
S105
1
-
S106
5
S104
BAND
S102
POWER
S107
S112
TUNE/
TIME SET
S111
CLOCK
+
1
2
A
B
C
D
E
F
G
H
3
4
5
6
7
8
9
10
11
12
Ref. No.
Location
D1
G-11
D2
G-11
D3
F-10
D4
G-8
D6
B-8
D7
B-10
D101
E-4
D102
D-5
D103
A-5
D104
G-2
D105
G-2
IC1
E-10
IC2
D-8
IC101
D-5
IC102
D-4
IC103
F-4
Q1
D-11
Q2
C-11
Q3
C-9
Q4
C-9
Q5
G-10
Q6
E-9
Q7
G-10
Q8
G-11
Q101
G-4
Q102
F-4
Q103
E-4
Q104
C-4
Q105
C-4
Q106
B-6
Q107
B-5
• Semiconductor
Location
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