Aiwa Z-A65, Руководство по обслуживанию, Страница: 41 / 58

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<FM Adjustment>
Make the following preparations for FM adjustment.
Preparations
• Standard Signal Generator (S.S.G.) / Loop antenna / Oscilloscope / Millivoltmeter / Dummy resistance (6
W
)
1) Connect the unit and measuring instruments as shown in the diagram below.
2) Connect the output of S.S.G. to the antenna input of the unit.
7. Tracking Adjustment
Requirements: As instructed in preparations.
• Adjustment point: L903
1) Set S.S.G. to FM; carrier of 87.5 MHz with 75 kHz modulation, and source at 1 kHz.
2) Tune the receiving frequency of the unit at FM 87.5 MHz.
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 L903 so that the millivoltmeter points maximum.
8. Separation Check
Requirements: As instructed in preparations.
1) Set S.S.G. to FM; carrier of 98 MHz with 67.5 kHz modulation, source at 1 kHz, and output at 60 dBuV.
2) Switch S.S.G. to PILOT ON, and set PILOT at 7.5 kHz.
3) Tune the receiving frequency of the unit at FM 98 MHz.
4) Allow the output of S.S.G. only from Lch, and check that the difference between Lch and Rch is 25 dB or above.
5) Apply the above check to Rch.
9. Auto-Stop Check
Requirements: As instructed in preparations.
1) Set S.S.G. to FM; carrier of 98 MHz with 75 kHz modulation, source at 1 kHz, and output at 10 ~ 35 dBuV or less.
2) Apply the tuning search function, and check that the unit automatically stops at FM 98 MHz.
DUMMY
SPOUT(L)
AC MILLIVOLTMETER
CH2 CH1
6
Ω
OUTPUT
OSCILLOSCOPE
CH2 CH1
LOAD
SET
Standard Signal Generator
FM ANT
SPOUT(R)