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<TUNER Adjustment>
1. AM VT Check
Requirement:
•
Measuring instrument: Digital multimeter
Test points: TP1 (VT), GND
1) Connect the digital multimeter between TP1 (VT) and GND.
2) Set to AM 1,710kHz.
3) Check that the digital multimeter indicates 9V or less.
4) Turn to the receiving frequency at 530kHz.
5) Check that the digital multimeter indicates 0.5V or above.
2. FM VT Adjustment and Check
Requirement:
•
Measuring instrument: Digital multimeter
Test points: TP1 (VT), GND
Adjustment location: L907
1) Connect the digital multimeter between TP1 (VT) and GND.
2) Set to FM 108.0MHz.
3) Adjust L907 so that the digital multimeter indicates 7.0
±
0.1V.
4) Tune the receiving frequency at 87.5MHz.
5) Check that the digital multimeter indicates 1.5V or less.
3. Clock Check
Requirement:
•
Measuring instrument: Frequency counter
Test point: TP2 (CLK), GND
1) Connect the frequency counter between TP2 (CLK) and GND.
2) Set to AM 1,710kHz.
3) Check that the frequency counter indicates 2,160kHz
±
45Hz.
<AM Adjustment>
Make the following preparation for AM adjustment.
Preparation
•
Standard Signal Generator (S.S.G.) / Loop antenna / Oscilloscope / Millivoltmeter / Dummy resistance (6
Ω
)
1) Connect the unit and measuring instruments as shown in the diagram below.
2) Position the loop antenna connected to S.S.G. and the one connected to the unit 60cm apart.
Requirement: As instructed in preparation.
•
Adjustment location: L802
1) Set S.S.G. to AM; carrier of 1000kHz with 30% modulation, and source at 1kHz.
2) Tune the receiving frequency of the unit at AM 1000kHz.
3) While monitoring the waveform at 1kHz through the oscilloscope, lower the output level of S.S.G. maximum (till a certain degree of
noise is monitored).
4) Adjust L802 so that the millivoltmeter points maximum.
6
Ω
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