Electrical Adjustments; Tuner Section - Sony ZS-2000 Service Manual

5-1. TUNER SECTION

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 µF
15 kHz frequency
deviation by 1 kHz 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
i jack (J401)
• 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.
SECTION 5

ELECTRICAL ADJUSTMENTS

0 dB = 1 µV
FM antenna
(JW1,2)
set
Put the lead-wire
antenna close to
the supplied
MW/LW loop antenna.
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: TUNER board (See page 20.)
– 19 –
CHECK
87.5 MHz 108 MHz
1.4 ± 0.2 V 6.9 ± 0.2 V
<confirmation> <confirmation>
<confirmation>
108 MHz
ADJUSTMENT
531 kHz 1,611 kHz
0.9 ± 0.1 V 4.9 ± 0.5 V
L5 <confirmation>
CT1
1,404 kHz
T1
999 kHz
ADJUSTMENT
153 kHz 279 kHz
0.7 ± 0.2 V 5.2 ± 0.1 V
<confirmation>
CT2
261 kHz
CT3