CMT-HX30R, HCD-HX30R - Sony Audio Service Manual (repair manual). Page 13

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HCD-HX30R
13
SECTION  5
ELECTRICAL  CHECKS
FM  TUNE  LEVEL  CHECK
signal
generator
set
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 MW 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.
FOCUS  BIAS  CHECK
+
CD board
TP121 (RFI)
TP124 (VC)
oscilloscope
(DC range)
Procedure:
1.  Connect oscilloscope to TP121 (RFI) and TP124 (VC) on the 
CD board.
2.  Press the [
?
/
1
] button to turn the power on, and press [
Z
] the 
button to open the disc tray.
3.  Set disc (YEDS-18) on the disc tray and press the [CD 
u
button to playback.
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. 
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
0.9 ± 0.4 Vp-p
Checking Location:
TUNER  SECTION
CD  SECTION
TP124
(VC)
– CD Board (Conductor Side) –
TP121
(RFI)
IC101
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