Aiwa NSX-TR77 Service Manual page 37

ELECTRICAL ADJUSTMENT -3/7
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<AM Adjustment>
Make the following preparations for AM adjustment.
Preparations
• Standard Signal Generator (S.S.G.) / Loop antenna / Oscilloscope / Millivoltmeter / Dummy resistance (6Ω)
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 60 cm apart.
Standard Signal Generator
4. Tracking Adjustment
Requirements: As instructed in preparations.
• Adjustment point: L952 / L953
1) Set S.S.G. to AM; carrier of 1,000 kHz with 30% modulation, and source at 1 kHz, position output at maximum.
2) Tune the receiving frequency of the unit at AM 1,000 kHz.
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 L952 so that the millivoltmeter points maximum.
5) Set S.S.G. to AM; carrier of 600 kHz with 30% modulation, and source at 1 kHz.
6) Tune the receiving frequency of the unit at AM 600 kHz.
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7) Adjust L953 so that the millivoltmeter points maximum.
8) Repeat above steps 1) to 7) 2 to 3 times.
5. Auto-Stop Check
Requirements: As instructed in preparations.
1) Set S.S.G. to AM; carrier of 1,000 kHz with 30% modulation, source at 1 kHz, and output of 74 dBuV.
2) Apply the tuning search function, and check that the unit automatically stops at AM 1,000 kHz.
6. IF Adjustment
Requirements: As instructed in preparations.
• Adjustment point: L802
1) Set S.S.G. to AM; carrier of 1,000 kHz with 30% modulation, and source at 1 kHz, position output at maximum.
2) Tune the receiving frequency of the unit at AM 1,000 kHz.
3) While monitoring the waveform at 1 kHz 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.
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AC MILLIVOLTMETER
DUMMY
LOAD
SET
SPOUT(L)
SPOUT(R)
6Ω
Q Q
3 6 7 1 3 1 5
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-37-
9 4 2 8
OSCILLOSCOPE
OUTPUT
CH1 CH2
CH1 CH2
0 5 8 2 9 9 4 2 8
m
9 9
9 9