Sony ICF-C490 / ICF-CD863 / ICF-CD863L Service Manual ▷ View online
ICF-C490
5
2-3.
MAIN BOARD
•
MAIN BOARD SETTING
1
knob (band)
qs
claw
3
2
screw (P3
×
14)
qd
main board
6
speker (6.6 cm) (SP1)
5
LED board
9
washer
8
two screws
(P3
(P3
×
14)
7
screw
(PTPWH3
(PTPWH3
×
8)
qa
power cord (PC1)
0
power board
9
washer
4
antenna (wire) (W7)
knob (vol)
knob (tuning)
B
A
RV1
shaft of CV1
Note 1 : When installing the main board,
adjust RV1 and the knob (vol).
Note 2 : When installing the main board,
turn the shaft of CV1 in the direction
of arrow
of arrow
A
fully and the knob (tuning)
in the direction of arrow
B
fully
before adjusting the shaft of CV1
and the knob (tuning).
and the knob (tuning).
6
ICF-C490
0 dB = 1
µ
V
[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
frequency coverage and tracking adjustments should be finally
done by the trimmer capacitors.
done by the trimmer capacitors.
• Remove FM antenna in FM adjustments.
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
MAIN board
TP (SP –)
TP (SP –)
MAIN board
TP (SP +)
TP (SP +)
set
MAIN board
TP (FM ANT)
TP (FM ANT)
8
Ω
0.01
µ
F
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter
T1
455 kHz
AM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter
L4
515 kHz
CT1-4
1,750 kHz
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L1
600 kHz
CT1-1
1,400 kHz
FM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter
L3
86.5 MHz
CT1-3
109.5 MHz
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L-2
86.5 MHz
CT1-2
109.5 MHz
SECTION 3
ELECTRICAL ADJUSTMENTS
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
8
Ω
MAIN board
TP (SP –)
TP (SP –)
MAIN board
TP (SP +)
TP (SP +)
ICF-C490
7
7
Adjustment Location :
– MAIN BOARD (Component Side) –
– MAIN BOARD (Conductor Side) –
FM Frequency Coverage Adjustment
T1
AM IF Adjustment
TP
(FM ANT)
TP
(SP –)
TP
(SP +)
L3
CT1-3
CT1-3
FM Tracking Adjustment
CT1-2
L2
L2
AM Frequency Coverage Adjustment
CT1-4
L4
L4
AM Tracking Adjustment
CT1-1
L1
L1
ICF-C490
8
8
SECTION 4
DIAGRAMS
4-1.
BLOCK DIAGRAM
D202
ALARM
BUZZER
BUZZER
D201
ALARM
RADIO
S101-1
ALARM MODE
BRIGHTNESS
RV1
VOL
S107
ALARM RESET
RADIO ON
• SIGNAL PATH
: FM
: AM
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
CF2
CF1
FM
RF
RF
FM
IF IN
IF IN
3
FM
DISCRIMINATOR
TUNING METER
FM
DISCRI
DISCRI
28
AF
OUT
SP1
AF
IN
IN
24
25
DET
OUT
AM
IF IN
IF IN
METER
NF
VOL
16
5
FM/AM
BAND
SELECT
AM OSC
L4
AM OSC
L3
FM OSC
L1
AM FERRITE-ROD
ANTENNA
W7
FM LEAD
ANTENNA
FM OSC
AM
RF IN
RF IN
9
REG OUT
B+
L2
FM RF
FM/AM FRONT-END,
FM/AM IF AMP, DET, AGC, AF AMP
IC1
MODE CONTROL, LED DRIVER
IC101
CV1-2
CT1-2
+
+
CT1-3, L3
FM FREQUENCY
COVERAGE
CV1
TUNING
S103
TIME SET +
S104
TIME SET FAST +
S105
TIME SET FAST –
POWER BACK UP
FOR CLOCK
FOR CLOCK
S106
ALARM RESET
RADIO OFF
CT1-1, L1
AM TRACKING
CT1-2, L2
FM TRACKING
T1
AM IF
MUTING
Q1
PC1
IC1 B+
IC101 B+
ALM-2 OUTPUT
20
RADIO OUTPUT
18
ALM-1 OUTPUT
19
D305
IC101 B+
IC101 B+
RECT
D302, 303
RIPPLE FILTER
Q2
SWITCH
Q301
T301
POWER
TRANSFORMER
RECT
D106, 107
S1
BAND
S111
BUZZER VOLUME
CV1-1
CT1-1
CV1-4
CT1-4
CV1-3
CT1-3
HOLD
RADIO
BUZZER
CLOCK
CV1
TUNING
SPEED
POWER
DOWN
Q103
SWITCHING
IC101 B+
S105
S104
"M"
"H"
17
50/60Hz INPUT 25
FM
AM
NORMAL
LOUD
QUIET
AM & 10
´
S HR AG & DE
1
PM & 10
´
S HR B
2
10
´
S HR C & HR E
3
HR B & G
4
HR C & D
5
HR A & F
6
10
´
S MIN A & F
7
10
´
S MIN B & G
8
10
´
S MIN C & D
9
10
´
S MIN E & MIN E
10
MIN B & G
11
MIN C & D
12
MIN A & F
13
TIME SET
22
ON/OFF INPUT
23
LED101
LED DISPLAY
S103
"L"
S107
S106
"L"
"H"
SLP/SNZ INPUT
24
S108
S109
"L"
"H"
ALARM SELECT
21
MODE SELECT
26
DRY BATTERY
6F22
(IEC DESIGNATION 6F22)
1PC. 9V
CT1-4, L4
AM FREQUENCY
COVERAGE
S108
SLEEP
S109
SNOOZE
(Singapore)
S102
S102-1
ALARM TIME/
CLOCK SET
RT
-TIME DIMMER
27
S102-2
S110
LOW
HIGH
RADIO+BUZZER
BUZZER
RADIO
OFF
D103
D102
S101-2
ALARM MODE
RADIO+BUZZER
BUZZER
RADIO
OFF
D108
D104
Q101
SWITCHING
SWITCH
Q102
(AC IN)
4
Click on the first or last page to see other ICF-C490 / ICF-CD863 / ICF-CD863L service manuals if exist.