Read Sony XR-1790 Service Manual online
– 14 –
AM Auto Scan/Stop Level Adjustment
Setting:
[TUNER]
button: AM
FREQUENCY SELECT switch: AM 9 k (E model only)
Procedure:
1. Tune the set to 999 kHz
2. Connect the digital voltmeter to TP2 (SD) on MAIN board.
3. Adjust RV1 on TU100 so that the reading on the digital volt-
1. Tune the set to 999 kHz
2. Connect the digital voltmeter to TP2 (SD) on MAIN board.
3. Adjust RV1 on TU100 so that the reading on the digital volt-
meter changes point from low to high.
Adjustment Location: See page 15.
FM Stereo Separation Adjustment
Setting:
[TUNER]
button: FM1
FREQUENCY SELECT switch: FM 50 k (E model only)
Procedure:
L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.
R-CH Stereo separation: C-D
The separations of both channels should be equal.
Specification: Separation more than 26 dB
Adjustment Location: See page 15.
FM Stereo
Level meter
Level meter
signal generator
connection
reading (dB)
output channel
L-CH
L-CH
A
B
R-CH
L-CH
Adjust RV4 on TU100
for minimum reading.
R-CH
R-CH
C
D
L-CH
R-CH
Adjust RV4 on TU100
for minimum reading.
FM RF signal
generator
Carrier frequency : 98.0 MHz
Output level
Output level
: 76 dB (6.3 mV)
Mode
: stereo
Modulation
: main: 1 kHz, 33.75 kHz deviation (45%)
sub: 1 kHz, 33.75 kHz deviation (45%)
19 kHz pilot: 7.5 kHz deviation (10%)
sub: 1 kHz, 33.75 kHz deviation (45%)
19 kHz pilot: 7.5 kHz deviation (10%)
0.01
µ
F
set
antenna jack (CN900)
+
–
–
speaker out terminal
level meter
4
Ω
AM RF signal
generator
Carrier frequency : 999 kHz
30% amplitude
modulation by
1 kHz signal
Output level
30% amplitude
modulation by
1 kHz signal
Output level
: 33 dB (44.7
µ
V)
(50
Ω
)
set
AM dummy antenna
30
Ω
15 pF
65 pF
antenna jack (CN900)
+
–
–
TP2 (SD)
MAIN board
digital
voltmeter
voltmeter
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