Pioneer sx-550 User manual

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9. ADJUSTING PROCEDURES
9. 1 AM SECTION
1. Through a 1k ohm resistor, connect an AM
signal generator to the AM antenna terminal.
Set for 400H2 at 30dB and 30Vo modulation.
2. Connect AC VM (Voltmeter) to TAPE REC
jack (L or R).
3. Set FUNCTION switch to AM position.
4. Set AM SG and SX-550 dial indication to point
A (600kHz).
5. Adjust TO for rnurirnum indication on AC VM.
6. Set AM SG and SX-550 dial indication to point
C (1,400kH2).
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7. Adjust TC4 for maximum indication on AC
VM.
8" Again set AM SG and SX-550 dial indication to
point A.
9. Adjust bar antenna core for maximum indica-
tion on AC VM.
10. Return AM SG and SX-550 dial indication to
point C.
11. Adjust TC5 for murimum indication on AC
VM.
12. Repeat steps A-tl to eliminate variations in
AC VM indications at points A and C.
AM signal generator
1 k ohm resistor
AC voltmeter
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9.2 FM SECTION
1. Through 300 ohm dummy antenh?, connect
FM signal generator to the 300 ohm FM
antenna terminals and set for 400H2 at 100d8
and !007o modul.ation.
2. Connect AC VM and distortion meter to TAPE
REC jack (L or R).
3. Set FUNCTIOI\tr switch to FM and MUTII\G
switch to OFF.
4. Set FM SG and SX-550 dial indication to point
A (90MHz).
5. Adjust TB for maximum indication on AC VM.
6. Adjust Tb lower core for center of scale indica-
tion on Tuning meter.
7 " Set FM SG for gdB output and adjust T1 and
T2 for maximum indication on AC VM.
8. Set FM SG and SX-550 dial indication to point
C (106N{Hz).
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9" Adjust TC3, then TC1 and TCz for maximum
indication on AC VM.
10. Again set FM SG and SX-550 dial indication to
point A.
11. Adjust T3, then T1 and T2 for maximum indi-
cation on AC VM.
72. Repeat steps B ^'11 to eliminate variations in
sensitivity at points A and C.
13. Adjust T4 for maximum sensitivity.
74. Detune to noise only and adjust T5 lower core
for center of scale indication on Tuning meter.
15. Set SX-550 dial indication to point B (98tTHz t
and adjust FM SG for center of scale indication
on Tuning meter.
16. Set FM SG output to 60dB and adjust T5
upper core for minimum distortion.
L7 . Repeat steps 14^'16 to eliminate variations in
minimum distortion position.
AC voltmeter Distortion meter
FM signal generator
300 ohm
dummy antenna
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9.3 MPX SECTION
1. Through 300 ohm dummy antenna) connect FM
signal generator to 300 ohm FM antenna
terminals.
2. Connect multiplex signal generator to external
modulation terminals of FM SG.
3. Connect oscilloscope horizontal input to MPX
SG pilot output and vertical input via probe to
TP (No. 31) of circuit board.
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4. Set SX-550 dial indication to 98MHz and adjust
FM SG for center of scale indication on Tuning
meter.
5. With FM SG unrnodulated, adjust VR1 so that
trissajous pattern on oscilloscope becomes sta-
tionary.
6. With MPX SG modulation 1kHz, L + R 67 .5kHz
deviation and Pilot 7 .lk}Jz deviation, adjust T4
for minimum distortion.
Oscilloscope
M PX signal generator
Probe
AC voltmeter D istortion meter
FM signal generator
300 ohm
dummy antenna
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9.4 POWER AMPLI FIER (IDLE CURRENT)
1. Set BASS and TREBLE controls to FLAT
positions.
2. Connect DC voltmeter to circuit board TP
terminals (L = 34 @, 33 O; R - 35 @, 36 O ) and
adjust VR3 (L) and VR4 (R) for 25mV.
3. Readjust after approximately 15 minutes (speci-
fication range is 15mV to 40mV).
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DC voltmeter
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