Aiwa CSD-FD79 Service Manual page 30

ELECTRICAL ADJUSTMENT - 2/5
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<AM Adjustment>
Make the following preparation for AM adjustment.
Preparation
• Measuring instruments: Standard Signal Generator (S.S.G)/Loop antenna/Oscilloscope/Millivoltmeter
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.
Standard Signal Generator
3. AM IF Adjustment
Requirement:
• Test point: HP OUT
• Adjustment location: L006
1) Set S.S.G. to AM, carrier of 1400 or 1404KHz with 30% modulation, and source at 1KHz.
2) Tune the receiving frequency of the unit at AM 1400 or 1404KHz.
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).
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4) Adjust L006 so that the millivoltmeter points maximum.
4. AM Tracking Adjustment
Requirement:
• Test point: HP OUT
• Adjustment locations: L003(BAR-ANT), TC001
1) Adjust TC001 so that the mechanical center.
2) Set S.S.G. to AM, carrier 600 or 603KHz with 30% modulation, source at 1KHz, and output at maximum.
3) Tune the unit to the receiving frequency at AM 600 or 603KHz.
4) While monitoring the waveform at 1KHz through the oscilloscope, lower the output level of
S.S.G. maximum (till a certain degree or noise is monitored).
5) Adjust L003(BAR-ANT) so that the millivoltmeter indicates maximum.
6) Set S.S.G. to AM, carrier 1400 or 1404KHz with 30% modulation, source at 1KHz.
7) Turn the unit to the receiving frequency at AM 1400 or 1404KHz.
8) While monitoring the waveform at 1KHz through the oscilloscope, lower the output level of
S.S.G. maximum (till a certain degree or noise is monitored).
9) Adjust TC001 so that the millivoltmeter indicates maximum.
10) Repeat the above step 2 to 9 two to three time.
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2 9
8
AC MILLIVOLTMETER
SET
HP OUT(L)
HP OUT(R)
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3 6 7 1 3 1 5
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-30-
9 4 2 8
OSCILLOSCOPE
OUTPUT
CH2
CH1
CH1 CH2
0 5 8 2 9 9 4 2 8
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9 9
9 9