Read Sony ICF-CD873 Service Manual online
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AM IF ADJUSTMENT
Adjust for a maximum reading on level meter
T1
450 kHz
AM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L4
530 kHz
2.8 V
Confirmation
1,710 kHz
9.5V
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L3
580 kHz
CT2
1,490 kHz
FM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L2
87.5 MHz
2.1 V
Confirmation
108 MHz
8.5 V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L1
87.5 MHz
CT1
108 MHz
Adjustment Location: MAIN board (See page 11)
FM VCO Adjustment
Setting:
Procedure:
1. Connect the frequency counter to TP7, 8 as shown the figure
1. Connect the frequency counter to TP7, 8 as shown the figure
below.
2. Tune the set to 98 MHz.
3. Adjust RV1 for 76 kHz reading on the frequency counter.
3. Adjust RV1 for 76 kHz reading on the frequency counter.
Specified Value: 75.95 to 76.05 kHz
Adjustment Location: MAIN board (See page 13)
SECTION 5
ELECTRICAL ADJUSTMENTS
TUNER SECTION
0 dB=1 µV
[AM]
Setting:
Function
Function
: RADIO
Band switch : AM
[FM]
Setting:
Function
Function
: RADIO
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.
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
2
jack (J301)
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
2
jack (J301)
set
32
Ω
0.01
µ
F
MAIN board
TP12 (FM IN)
TP12 (FM IN)
digital voltmeter
100 k
Ω
MAIN board
TP53 (VT)
FM RF SSG
Carrier frequency: 98 MHz
Modulation: 400 Hz, 30% FM modulation
Output level: 0.1 V (100 dB)
Modulation: 400 Hz, 30% FM modulation
Output level: 0.1 V (100 dB)
MAIN board
TP12 (FM IN)
TP12 (FM IN)
0.01
µ
F
set
1
µ
F
TP8 (VCO)
+
–
–
frequency counter
33 k
Ω
TP7 (+B)
+
MAIN board
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