CMT-EH15, HCD-EH15 - Sony Audio Service Manual (repair manual). Page 12

Procedure:
1.  Turn on the set.
2.  Input the following signal from signal generator to FM antenna 

input directly.

Carrier frequency : A = 87.5 MHz, B = 98 MHz, C = 108 MHz
Deviation 

: 75 kHz

Modulation 

: 1 kHz

ANT input 

: 35 dBu (EMF)

Note:  Use 75 ohm coaxial cable to connect signal generator and the set. 

You cannot use video cable for checking.

 

Use signal generator whose output impedance is 75 ohm. 

3.  Set to FM tuner function and tune A, B and C signals.
4. Confi rm “TUNED” is lit on the display for A, B and C sig-

nals.

When the selected station signal is received in good condition, 
“TUNED” is displayed.

Note:
1.  CD Block is basically constructed to operate without adjustment.
2.  Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3.  Use an oscilloscope with more than 10 M

Ω impedance.

4.  Clean the object lens by an applicator with neutral detergent when the 

signal level is low than specifi ed value with the following checks.

5.  Check the focus bias check when optical pick-up block is replaced.

Procedure:
1.  Connect oscilloscope to TP122 (RFEQO) and TP124 (VC) on 

the CD board.

2.  Press the [

?

/

1

] button to turn the power on.

3.  Set the disc (YEDS-18) and press the [CD 

u

] button to play-

back.

4. Confi rm that oscilloscope waveform is as shown in the fi gure 

below. (eye pattern)

 

A good eye pattern means that the diamond shape (

◊) in the 

center of the waveform can be clearly distinguished.