XR-C4120 - Sony Car Audio Service Manual (repair manual). Page 14

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 0 dB=1 µV

When the tuner unit is defective, replace it by a new one be-
cause its internal block is difficult to repair.

Adjust the tuner section in the sequence shown below.

1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment
3. AM (MW) Auto Scan/Stop Level Adjustment

[SOURCE]

 button: FM

1. Set to the test mode. (See page 13)
2. Push the 

[SOURCE]

 button and set to FM.

Display

3. Adjust with the volume RV2 on TU1 so that the “FM” indica-

tion turns to “FM0” indication on the display window.
But, in case of already indicated “FM0”, turn the RV2 so that
put  out light “0” indication and adjustment.

Display

Adjustment Location: See page 16.

FM RF signal

generator

Carrier frequency

: 98.0 MHz

Output level

: 22 dB (12.6 

µ

V)

Mode

: mono

Modulation

: 1 kHz, 22.5 kHz deviation (30%)

0.01 

µ

F

set

antenna jack (J1)

SHUF

SHUF

[SOURCE]

 button: FM

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 TU1

for minimum reading.

R-CH

R-CH

C

D

L-CH

R-CH

Adjust RV4 on TU1

for minimum reading.

L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.

Specification: Separation more than 30 dB

Adjustment Location: See page 16.

FM RF signal

generator

Carrier frequency : 98.0 MHz
Output level

: 70 dB (3.2 mV)

Mode

: stereo

Modulation

: main: 1 kHz, 20 kHz deviation (26.7%)
  sub: 1 kHz, 20 kHz deviation (26.7%)

:

 19 kHz pilot: 7.5 kHz deviation (10%)

0.01 

µ

F

set

antenna jack (J1)

+
–

AUDIO OUT
jack (J331)

level meter

10 k

Ω