Fm Noise Focus Adjustment (Xr-1804 Only); Mw Auto Scan/Stop Level Adjustment; Fm Stereo Separation Adjustment - Sony XR-1800 Service Manual

FM Noise Focus Adjustment (XR-1804 only)

Setting:
[TUNER]
button: FM1
FREQUENCY SELECT switch: FM 50 k
FM RF signal
antenna jack (CN900)
generator
0.01 µ F
Carrier frequency : 98.0 MHz
Output level : 60 dB (1 mV)
Mode : mono
Modulation : 1 kHz, 75 kHz deviation (100%)
Procedure:
1. Tune the 98.0 MHz.
2. The then output level is supposing that (A) dB.
3. Adjust with the volume RV3 on TU100 so that the output level
is (A) –32 dB then signal generator input set to –20 dB.
Adjustment Location: See page 13.

FM Stereo Separation Adjustment

Setting:
[TUNER]
button: FM1
FREQUENCY SELECT switch : FM 50 k (XR-1804 only)
FM RF signal
antenna jack (CN900)
generator
0.01 µ F
Carrier frequency : 98.0 MHz
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%)
Procedure:
FM Stereo
Level meter
signal generator
connection
output channel
L-CH
R-CH
R-CH
L-CH
L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.
Specification: Separation more than 26 dB
Adjustment Location: See page 13.
level meter
4 Ω
+
set
–
speaker out terminal
level meter
4 Ω
+
set
–
speaker out terminal
Level meter
reading (dB)
A
L-CH
B
L-CH Adjust RV4 on TU100
for minimum reading.
C
R-CH
D
R-CH Adjust RV4 on TU100
for minimum reading.

MW Auto Scan/Stop Level Adjustment

Setting:
[TUNER]
button: MW
FREQUENCY SELECT switch: MW 9 k (XR-1804 only)
AM RF signal
generator
AM dummy antenna
(50 Ω )
Carrier frequency : 999 kHz
30% amplitude
modulation by
1 kHz signal
Output level
MAIN board
TP2 (SD)
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-
meter changes point from low to high.
Adjustment Location: See page 13.
– 12 –
30 Ω 15 pF
antenna jack (CN900)
: 33 dB (44.7 µ V)
digital
voltmeter
+
–
65 pF
set