Aiwa NSX-R41, Service Manual

Page: 36 / 57

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ELECTRICAL ADJUSTMENT -4/7
<FM Adjustment>
Make the following preparations for FM adjustment.
Preparations
• Standard Signal Generator (S.S.G.) / Loop antenna / Oscilloscope / Millivoltmeter / Dummy resistance (6y)
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.
9. Tracking Adjustment
Requirements: As instructed in preparations.
• Adjustment point: L901/L902/L904/L905
1) Set S.S.G. to FM; carrier of 108 MHz with 75 kHz modulation, and source at 1 kHz, position output at maximum.
2) Tune the receiving frequency of the unit at FM 108 MHz.
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 L905
→
L904
→
L902
→
L901
→
L902
→
L904
→
L905. Repeat adjustment (L905, L904, L902, L901) two to three time so that
the millivoltmeter indicates the maximum level.
10. 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 74 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 12 dB or above.
5) Apply the above check to Rch.
11. 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 1kHz, and output at 10 to 35 dBuV or less.
2) Apply the tuning search function, and check that the unit automatically stops at FM 98 MHz.
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