Electrical Adjustments - Sony HCD-LX20i Service Manual

0 dB=1 μV
TUNER SECTION
[AM]
Setting:
Function: TUNER
Band: AM
loop antenna A
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
[FM]
Setting:
Function: TUNER
Band: FM
MAIN board
FM RF signal
J802 pin
generator
1 kHz frequency
deviation by FM 75 kHz
MAIN board
signal
J802 pin
Output level:
as low as possible
MAIN board
JW821 (VT)
JW828 (GND)
• Repeat the procedures in each adjustment several times, and
the tracking adjustments should be fi nally done by the trimmer
capacitors.
• Remove FM antenna in FM adjustment.
SECTION 5

ELECTRICAL ADJUSTMENTS

60 cm
loop antenna B
set
MAIN board
TP (TUNER OUT L-ch)
level meter
+
set
–
MAIN board
JW828
(GND)
digital voltmeter
10 k Ω
AM VT VOLTAGE CONFIRMATION
Frequency Display Reading on Digital Voltmeter
530 kHz
1,710 kHz
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L851
FM VT VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L805
Confi rmation
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L804
FM DETECTOR ADJUSTMENT
Setting:
Function: TUNER
BAND button: FM
FM RF Signal
generator
Carrier frequency : 98 MHz
Modulation : deviation by
Output level : 60 dB
1. Tune the set to 98 MHz.
2. Adjust L806 so that modulation distortion may become the
best in the vicinity of the maximum value where the tuner out
level becomes –15 dBs or more.
Adjustment Location:
– MAIN Board
(Component Side) –
L806
FM Detector
Adjustment
L804
FM Tracking
Adjustment
L805
FM VT Voltage
Adjustment
L851
AM Tracking
Adjustment
HCD-LX20i
1.6 ± 0.3 V
8 ± 0.5 V
620 kHz
87.5 MHz 1.7 ± 0.1 V
108 MHz 6.2 ± 0.5 V
98 MHz
MAIN board
TP (TUNER OUT L-ch)
set
MAIN board
FM 75 kHZ JW828 (GND)
– MAIN Board
(Conductor Side) –
TP
(TUNER
OUT L-ch)
TP
(TUNER
OUT R-ch)
JW828
(GND)
1
J802
3
JW821
(VT)
13