Electrical Adjustments - Sony ICF-M770L Service Manual

ICF-M770L/M770S/M770SL
0 dB=1 µV
[MW/LW]
Setting:
BAND switch: MW or LW
Put the lead-wire
AM RF signal
antenna close to
generator
the set.
set
30% amplitude
modulation by
400 Hz signal
Output level: as low as possible
[FM]
Setting:
BAND switch: FM
FM RF signal
MAIN board
generator
TP (ANT)
0.01 µF
set
22.5 kHz frequency
deviation by 400 Hz
signal
Output level: as low as possible
[SW] (ICF-M770S/M770SL)
Setting:
BAND switch: SW
AM RF signal
MAIN board
generator
TP (ANT)
11 pF
set
30% amplitude
modulation by
400 Hz signal
Output level: as low as possible
MAIN board
TP (VT)
• Repeat the procedures in each adjustment several times, and the
tracking adjustments should be finally done by the trimmer ca-
pacitors.
• Remove FM/SW antenna in FM/SW adjustment.
6
SECTION 4

ELECTRICAL ADJUSTMENTS

level meter
32 Ω
+
–
JACK board
v jack (J201)
level meter
32 Ω
+
–
JACK board
v jack (J201)
level meter
32 Ω
+
–
JACK board
v jack (J201)
digital voltmeter
100 kΩ
+
–
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter
T1
MW VT VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
(L8) [L10] 531 kHz
Confirmation 1,602 kHz
MW TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
(L5-1) [L5]
(CT1) [CT2]
LW VT VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
(CT3) 〈〈L10〉〉 153 kHz
Confirmation 279 kHz
LW TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
(L5-2) 〈〈L5〉〉
CT2
FM VT VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L14 87.5 MHz
Confirmation 108 MHz
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L12, 13
CT4
SW VT VOLTAGE ADJUSTMENT*
Adjustment Part Frequency Display Reading on Digital Voltmeter
L8 5,800 kHz
Confirmation 15,900 kHz
SW TRACKING ADJUSTMENT*
Adjust for a maximum reading on level meter
L3
CT1
*: ICF-M770S/M770SL
Adjustment Location: MAIN board (See page 7)
no mark : common
( ) : ICF-M770L
[ ] : ICF-M770S
〈〈 〉〉 : ICF-M770SL
450 kHz
2.5 ± 0.1 V [2.8 ± 0.1 V]
9.6 ± 1.0 V
603 kHz
1,404 kHz
2.2 ± 0.1 V 〈〈2.8 ± 0.1 V〉〉
8.6 ± 1.0 V
162 kHz
243 kHz
2.9 ± 1.0 V
9.1 ± 1.0 V
87.5 MHz
108 MHz
2.7 ± 0.1 V
9.1 ± 1.0 V
5,800 kHz
15,900 kHz