Sony ICF-M770L / ICF-M770S / ICF-M770SL Service Manual ▷ View online
ICF-M770L/M770S/M770SL
4
• This set can be disassembled in the order shown below.
3-1.
DISASSEMBLY FLOW
SECTION 3
DISASSEMBLY
Note:
Follow the disassembly procedure in the numerical order given.
3-2.
CABINET (REAR) ASSY
3
telescopic antenna (ANT1)
2
screw (P3
×
10)
1
six screws
(BTP3
(BTP3
×
14)
6
cabinet (rear) assy
5
Remove five solders.
4
main board
main board
SET
3-2. CABINET (REAR) ASSY
(page 4)
3-4. MAIN BOARD
(page 5)
3-3. CHASSIS ASSY
(page 5)
ICF-M770L/M770S/M770SL
5
3-3.
CHASSIS ASSY
3-4.
MAIN BOARD
4
chassis assy
1
knob (jog)
2
knob (control) (vol)
3
knob (control) (tone)
5
main board
4
three claws
4
claw
2
claw
3
key board
1
two screws
(P2
(P2
×
8)
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