Alignment Procedure; English.17 - Pioneer SX-939 Service Manual

10. ALIGNMENT PROCEDURE
10.1 ENGLISH
ALIGNING THE FM SECTION
1. SX-939 Control Settings
Set the controls (knob and switches) of the SX-939 as follows:
POWER: ON
FUCTION: FM
FM MUTING: OFF
2. Connections between Test Equipment and the SX-939
• The output from an FM signal generator should be connected to the 300fi antenna terminals
of the SX-939.
• A distortion meter should be connected to the TAPE REC terminal jacks on the SX-939.
• An AC millivolt meter should be connected to the TAPE REC terminal jacks on the SX-939
in parallel with the distortion meter.
3. Set both the FM signal generator and the SX-939 to indicate 98MHz.
4. Turn the FM signal generator output level down to minimum.
5. Turn the lower core and adjust so that the TUNING meter needle is centered. ,
6. Increase the FM signal generator output to 60dB, modulated at 400Hz, with a deviation of ±75
kHz.
7. Turn the upper core and adjust so that the distortion is at a minimum.
Steps 4 ~ 7 above should be repeated several times in succession, until no significant improve¬
ment is obtained.
8. Set the FM signal generator output level to lOdB, modulated at 400Hz, with a frequency devia¬
tion of ±75 kHz.
9. Adjust for maximum output at 90MH&-
10. Adjust for maximum output at 106MHz.
11. Adjust for maximum output at 90MHz. j
12. Adjust for maximum output at 106MHz.-|
Steps 11 ~ 12 above should be repeated several times in succession, until no further significant
improvement is obtained.
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