Read Sony ICF-C900HS Service Manual online
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SECTION 3
ELECTRICAL ADJUSTMENTS
TUNER SECTION
[FM]
Setting:
BAND switch: FM
BAND switch: FM
[AM]
Setting:
BAND switch: AM
BAND switch: AM
• 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.
FM RF signal
generator
generator
400 Hz, 30% FM modulation
frequency deviation
frequency deviation
±
22.5 kHz
Output level: as low as possible
MAIN board
TP (FMIN)
TP (FMIN)
0.01
µ
F
AM RF signal
generator
generator
400 Hz, 30%
AM modulation
Output level: as low as possible
AM modulation
Output level: as low as possible
Put the lead-wire
antenna close to
the set.
antenna close to
the set.
level meter
8
Ω
+
–
–
MAIN board
TP (SP-OUT)
TP (SP-OUT)
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.
L2
86.5 MHz
CT1-2
109.5 MHz
AM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter.
L4
520 kHz
CT1-4
1,650 kHz
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L1
600 kHz
CT1-1
1,400 kHz
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1
455 kHz
DATA TX SECTION
DATA TRANSMISSION LEVEL ADJUST
Setting:
RANDOM switch: OFF
RANDOM switch: OFF
Schematic Diagrams of the filter unit:
Adjusting Procedure:
1. Insert the AC plug of set into the AC Outlet of filter unit while
1. Insert the AC plug of set into the AC Outlet of filter unit while
pressing
[D.S.T SUMMER T]
,
[CLOCK]
,
[SNOOZE/DATE/SLEEP OFF]
buttons simultaneously.
2. All LCD segment are turned on, and the test mode will start.
3. Press all button one by one as below,
3. Press all button one by one as below,
[D.S.T SUMMER T]
,
[CLOCK]
,
[TIME SET–]
,
[TIME SET+]
[ALARM A]
,
[ALARM B]
,
[LIGHT 1]
,
[LIGHT 2]
[SNOOZE/DATE/SLEEP OFF]
,
[RADIO OFF, ALARM SET]
[RADIO ON, SLEEP]
4. Set
[RANDOM]
Switch to OFF
n ON n OFF position, and
the display “OFF TIME0*” are appear.
5. Press
[1]
button to blink the display “OFF TIME*” and the
carrier signal output continuity,
(*: ID code No.)
(*: ID code No.)
6. Adjust T2 to 0.45 V observing AC voltmeter.
Adjustment Value:
Adjustment part
STANDARD VALUE
T2
0.35 V to 0.55 V
7. To exit from test mode, disconnect the power cord of set.
filter unit
AC voltmeter
AC outlet
measure
terminal
terminal
AC120 V, 60 Hz
set
+
–
–
AC outlet
measure
terminal
terminal
11
Ω
62
Ω
0.1
µ
F
0.1
µ
F
1 mH
1 mH
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