Tuner Section - Sony PMC-R30L Service Manual

TUNER SECTION

0 dB = 1 µV
Precautions in Repairing
Note : As a tuner unit (TU1) is difficult to repair if faulty,
replace it with new one.
• FM Section
Setting:
BAND button: FM
FM RF signal
generator
0.01 µ F
22.5 kHz frequency
deviation by 400 Hz signal
output level : as low as possible
• MW/LW Section
Setting:
BAND button: MW or LW
AM RF signal
generator
30% amplitude
modulation by 400 Hz signal
output level : as low as possible
• Connecting Level Meter (FM, MW and LW)
32 Ω
set
phones jack (J302)
• Connecting Digital Voltmeter (FM, MW and LW)
tuner board
TP (VT)
• Repeat the procedures in each adjustment several times, and the
frequency coverage and tracking adjustments should be finally
done by the trimmer capacitors.
FM terminal
(CNP2)
set
Put the lead-wire
antenna close to
the supplied
MW/LW loop aerial.
level meter
(range: 0.5-5 V ac)
digital
voltmeter
FM FREQUENCY COVERAGE
Frequency Display
Reading on Digital voltmeter
Adjustment Part
FM TRACKING CHECK
Adjust for a maximum reading on level meter.
<confirmation>
87.5 MHz
MW FREQUENCY COVERAGE
Frequency Display
Reading on Digital voltmeter
Adjustment Part
MW TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L3
621 kHz
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
LW FREQUENCY COVERAGE
Frequency Display
Reading on Digital voltmeter
Adjustment Part
LW TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L4
162 kHz
Adjustment Location: MAIN board (See page 14.)
– 13 –
CHECK
87.5 MHz 108 MHz
1.8 ± 0.2 V 5.6 ± 0.2 V
<confirmation> <confirmation>
<confirmation>
108 MHz
ADJUSTMENT
531 kHz 1,611 kHz
0.9 ± 0.1 V 5.6 ± 0.2 V
L5
CT2
1,404 kHz
CFT1
450 kHz
ADJUSTMENT
153 kHz 279 kHz
0.6 ± 0.1 V 5.3 ± 0.2 V
CT3 <confirmation>
CT1
261 kHz
CT4