Pioneer SX-939 Service Manual page 16

ALIGNING THE FM MPX SECTION
Notes: This set of adjustments should not be carried out until the alignment of the FM section
(1 — 12 above) has been completed.
The multiplex signal generator should be connected to the external modulator terminals
of the FM signal generator.
1. SX-939 Control Settings
Set the controls (knob and switch) of the SX-939 as follows:
POWER: ON
FUNCTION: FM
FM MUTING: OFF
2. Connections between the Test Equipment and the SX-939
• The output from the FM signal generator should be connected to the 3001T2 antenna
terminals of the SX-939.
• The output from the MPX signal generator should be connected to the external modulator
terminals of the FM signal generator.
• The oscilloscope X plates (horizontal inputs) should be connected to the PILOT OUT
terminals on the MPX signal generator, and the Y plates (vertical inputs) to terminal
number 18.
• The AC millivolt meter should be connected to the TAPE REC terminals (with changeover
possible from L to R channels).
3. Multiplex Signal Generator Modulation
L + R(lkHz): 67.5kHz deviation
PILOT (19kHz): 7.5kHz deviation
4. Set the FM signal generator output to minimum.
5. Adjust for a stationary Lissajous waveform on the oscilloscope^
6. Reset the FM signal generator to 60dB level output, and modulate either the L or R channel.
7. Adjust for the maximum separation. -
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-,
18