Sony ICF-M770L / ICF-M770S / ICF-M770SL Service Manual ▷ View online
6
ICF-M770L/M770S/M770SL
no mark : common
(
) : ICF-M770L
[
] : ICF-M770S
〈〈
〉〉 : ICF-M770SL
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter
T1
450 kHz
MW VT VOLTAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
(L8) [L10]
531 kHz
2.5
± 0.1 V [2.8 ± 0.1 V]
Confirmation
1,602 kHz
9.6
± 1.0 V
MW TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
(L5-1) [L5]
603 kHz
(CT1) [CT2]
1,404 kHz
LW VT VOLTAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
(CT3)
〈〈L10〉〉
153 kHz
2.2
± 0.1 V 〈〈2.8 ± 0.1 V〉〉
Confirmation
279 kHz
8.6
± 1.0 V
LW TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
(L5-2)
〈〈L5〉〉
162 kHz
CT2
243 kHz
FM VT VOLTAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L14
87.5 MHz
2.9
± 1.0 V
Confirmation
108 MHz
9.1
± 1.0 V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L12, 13
87.5 MHz
CT4
108 MHz
SW VT VOLTAGE ADJUSTMENT
*
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L8
5,800 kHz
2.7
± 0.1 V
Confirmation
15,900 kHz
9.1
± 1.0 V
SW TRACKING ADJUSTMENT
*
Adjust for a maximum reading on level meter
L3
5,800 kHz
CT1
15,900 kHz
*: ICF-M770S/M770SL
Adjustment Location: MAIN board (See page 7)
0 dB=1
µ
V
[MW/LW]
Setting:
BAND switch: MW or LW
BAND switch: MW or LW
[FM]
Setting:
BAND switch: FM
BAND switch: FM
[SW] (ICF-M770S/M770SL)
Setting:
BAND switch: SW
BAND switch: SW
• Repeat the procedures in each adjustment several times, and the
tracking adjustments should be finally done by the trimmer ca-
pacitors.
pacitors.
• Remove FM/SW antenna in FM/SW adjustment.
digital voltmeter
100 k
Ω
MAIN board
TP (VT)
+
–
–
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
+
–
–
level meter
set
32
Ω
11 pF
MAIN board
TP (ANT)
TP (ANT)
JACK board
v
jack (J201)
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
set
32
Ω
0.01
µ
F
MAIN board
TP (ANT)
TP (ANT)
JACK board
v
jack (J201)
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
JACK board
v
jack (J201)
SECTION 4
ELECTRICAL ADJUSTMENTS
ICF-M770L/M770S/M770SL
7
7
Adjustment Location:
– MAIN BOARD (Component Side) –
– MAIN BOARD (Conductor Side) –
TP
(VT)
TP
(ANT)
CT1
MW Tracking Adjustment (M770L)
L5-1
L13
L12
L12
FM Tracking Adjustment
CT4
CT2
MW Tracking Adjustment (M770S)
L5
LW Tracking Adjustment (M770SL)
CT1
SW Tracking Adjustment (M770S/M770SL)
L3
T1
AM IF
Adjustment
L14
FM VT Voltage
Adjustment
CT3
LW VT Voltage
Adjustment (M770L)
L8
MW VT Voltage Adjustment (M770L)
SW VT Voltage Adjustment (M770S/M770SL)
SW VT Voltage Adjustment (M770S/M770SL)
L10
MW VT Voltage Adjustment (M770S)
LW VT Voltage Adjustment (M770SL)
LW VT Voltage Adjustment (M770SL)
CT2
LW Tracking Adjustment (M770L)
L5-2
ICF-M770L/M770S/M770SL
8
8
SECTION 5
DIAGRAMS
5-1.
BLOCK DIAGRAM
13
10
15
18
11
6
8
FM
FRONT-END
FM
IF AMP
AF
POWER AMP
AM IF AMP,
AGC, DET
AM
FRONT-END
17
20
FM
RF IN
RF IN
FM/AM
IF OUT
CF3
10.7MHz
CF2
10.7MHz
CF1
450kHz
FM
RF
RF
FM
IF IN
IF IN
TUNING METER
28
AF
OUT
AF
IN
IN
24
25
DET
OUT
AM
IF IN
IF IN
METER
NF
VOL
16
4
5
FM/AM
BAND
SELECT
AM OSC
L8
SW/MW
OSC
L10
MW/LW
OSC
L14
FM OSC
L5
MW/LW
FERRITE-ROD
ANTENNA
FM OSC
AM
RF IN
RF IN
L12, 13
FM RF
FM/AM FRONT-END,
FM/AM IF AMP, DET, AGC, AF AMP
IC1
SYSTEM CONTROLLER,
LIQUID CRYSTAL DISPLAY DRIVER,
KEY CONTROL
IC104
CT2
D2-1
Q6
MW/LW
SWITCH
MW/LW
SWITCH
Q4
MW/LW
SWITCH
Q7
CT3
CT4
RV1
VOL
+
+
L14
FM VT VOLTAGE
D104, 105
(LCD BACK LIGHT)
CT3
LW VT
VOLTAGE
L10
LW VT
VOLTAGE
CT4, L12, 13
FM TRACKING
T1
AM IFT
T1
AM IF
B.P.F.
BPF1
LOW-PASS FILTER
Q104, 110
• SIGNAL PATH
: FM
: MW/LW
D1-1
D6
D7
LIGHT
16
BEEP 52
15
AM/(FM/TV)
56
EO
19
(MW/LW)/SW
4
BPF
3
MUTE
2
AC DET
TUNED
14
VCOL
20
VCOH
25
24
X101
75kHz
XIN
XOUT
17
HOLD
LCD0 – LCD12
21
COM0 – COM3
KEY MATRIX
S101 – 119
35 – 47
31 – 34
KS0 – KS4
1, 6 – 9
KR0 – KR3
10 – 13
LIQUID CRYSTAL DISPLAY
LCD101
(M770L)
CT2, L5-2
LW TRACKING
(M770L)
CT1, L5-1
MW TRACKING
(M770SL)
CT2, L5
LW TRACKING
(M770S)
CT2, L5
MW TRACKING
CT1
Q11, 12
TONE
CONTROL
SWITCH
D1-2
(M770L)
ANT1
FM/SW
ANTENNA
CF4
10.7MHz
3
FM
DISCRIMINATOR
FM
DISCRI
DISCRI
SP1
J201
v
MUTING
SWITCH
SWITCH
Q9
LED DRIVE
Q107
D9
FM/(SW/MW/LW) BAND
SELECT SWITCH
Q10
FM VCO
BUFFER
BUFFER
Q8
FM VCO
BUFFER
BUFFER
Q105
M770S/
M770SL
M770S/
M770SL
SW
SWITCH
Q1
L3
SW
RF
FM/(SW/MW/LW) BAND
SELECT SWITCH
Q5
VCC B+
D2-2
SW
SWITCH
Q4
SW BAND
SELECT SWITCH
Q3
(M770L)
M770S/
M770SL
M770S/
M770SL
S120
HOLD
OFF
+3V B+
HOLD
T202
POWER
TRANSFORMER
RECT
D205, 206
J301
AC IN -
AC DETECT
Q201
AC DETECT
Q103
DRY BATTERY
SIZE "D"
(IEC DESIGNATION R20)
4PCS. 6V
D202 – 204
5
POWER
D201
VCC B+
+3V B+
B+ SWITCH
Q109
+3V
REGULATOR
IC101
DC/DC
CONVERTER
Q106, 111, T101
LOW-PASS
FILTER
CIRCUIT
B+
D102
RV2
TONE
REG OUT
9
REG +1.2V
50
VDET1
51
CEDET
BATTERY
VOLTAGE DETECT
IC102
53
VDET2
BATTERY
VOLTAGE DETECT
IC103
B+ SWITCH
Q101
POWER ON/OFF
CONTROL SWITCH
Q102
FM/(SW/MW/LW) BAND
SELECT SWITCH
Q108
(M770L)
L5-1
MW
FERRITE-ROD
ANTENNA
L5-2
LW
FERRITE-ROD
ANTENNA
REG
+1.2V
REG
+1.2V
REG
+1.2V
Q2
SW
SWITCH
VCC B+
(M770L)
M770S/
M770SL
M770S/
M770SL
M770S/
M770SL
CT1, L3
LW TRACKING
(M770SL)
L10
MW VT
VOLTAGE
(M770S)
L8
SW VT
VOLTAGE
(M770S/M770SL)
L8
MW VT
VOLTAGE
(M770L)
ICF-M770L/M770S/M770SL
9
9
Note on Printed Wiring Board:
•
•
X
: parts extracted from the component side.
•
Y
: parts extracted from the conductor side.
•
W
: indicates side identified with part number.
•
f
: internal component.
•
: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
5-2.
NOTE FOR PRINTED WIRING BOARD AND SCHEMATIC DIAGRAMS
Note on Schematic Diagram:
• All capacitors are in
• All capacitors are in
µ
F unless otherwise noted. pF:
µµ
F
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.
•
f
: internal component.
•
C
: panel designation.
• IC Block Diagram
IC1
CXA1019S
1
2
3
4
5
6
7
8
9
10
15
14
13
12
11
FM
DISCRIMINATOR
AF POWER AMP
AM FE
FM IF
TUNING
METER
AM IF DET AGC
FM FE
23
22
21
20
24
25
19
18 17 16
29 28 27 26
30
GND
GND
AF OUT
VCC
RIPPLE
FIL
TER
AF IN
DET OUT
AFC AGC
AFC AGC
IF GND
METER
N.C
FM IF IN
AM IF IN
FM/AM BAND
SELECT
FM/AM
IF OUT
FE GND
N.C
AM RF IN
FM RF
REG OUT
FM OSC
FM RF IN
AFC
AM OSC
VOL
NF
FM DISCRI
GND
GND
•
A
: B+ Line.
•
H
: adjustment for repair.
• Power voltage is dc 6 V and fed with regulated dc power
supply from battery terminal.
• Voltages and waveforms are dc with respect to ground in
no-signal (detuned) conditions.
no mark : FM
(
no mark : FM
(
) : SW
[
] : MW
〈〈
〉〉
: LW
• 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
: MW/LW
Note: The components identified by mark
0
or dotted line
with mark
0
are critical for safety.
Replace only with part number specified.
• Circuit Boards Location
jack board
main board
key board
inlet board
power board
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