CDX-C4840R, CDX-C4850R - Sony Car Audio Service Manual (repair manual). Page 18

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FM RF signal

generator

0.01 

µ

F

antenna
terminal

set

Carrier frequency : 98.00 MHz
Output level

: 22 dB (12.6 

µ

V)

Mode

: mono

Modulation

: 1 kHz, 22.5 kHz deviation (30%)

Procedure :
1. Set to the test mode.
2. Push the  SOURCE  button and set to FM.

Display

D-BASS switch : OFF
SOURCE button : FM

3. Push the preset  3  button.

Display

µ

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

This set have the test mode function. In the test mode, FM Auto
Scan/Stop Level and MW Auto Scan/Stop Level adjustments can
be performed easier than it in ordinary procedure.

<Set the Test Mode>
1. Set the “OFF” mode.
2. Push the preset  4  button.
3. Push the preset  5  button.
4. Press the preset  1  button for more than two seconds.
5. Then the display indicates all lights, the test mode is set.

<Release the Test Mode>
1. Push the  OFF  button.

The adjustments of tuner section, should be performed according
to the following sequence.
1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment
3. FM RDS S-Meter Adjustment
4. MW Auto Scan/Stop Level Adjustment

4. Adjust with the volume RV2 on TU601 so that the “FM”

indication 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 20.