Sony SS-CHP7 Service Manual page 27

CD SECTION
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 MΩ impedance.
4. Clean the object lens by an applicator with neutral detergent
when the signal level is low than specified value with the
following checks.
5. Check the focus bias check when optical block is replaced.
Focus Bias Check
BD board
TP (RF)
TP (VC)
Procedure :
1. Connect oscilloscope to TP (RF) and TP (VC) on the BD board.
2. Press the button to turn the power on.
?/1
3. Put disc (YEDS-18) in and press the
back.
4. Confirm that oscilloscope waveform is as shown in the figure
below. (eye pattern)
A good eye pattern means that the diamond shape ( ) in the
center of the waveform can be clearly distinguished.
oscilloscope
(DC range)
+
–
(CD) button to play-
N
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.0 ± 0.2 Vp-p
Checking Location:
– BD BOARD (Conductor Side) –
TP(RF)
80
1
IC721
TP(VC)
20
21
HCD-HP7
14 1
IC722
15 28
CN710
61
60
41
40
IC803
25