Sony HCD-HP7 - Page 25

25
HCD-HP7
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
Procedure :
1. Connect oscilloscope to TP (RF) and TP (VC) on the BD board.
2. Press the ?/1 button to turn the power on.
3. Put disc (YEDS-18) in and press the N (CD) button to play-
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.
+
–
BD board
TP (RF)
TP (VC)
oscilloscop
e
(DC range)
VOLT/DIV: 200 m
V
TIME/DIV: 500 ns
level:
1.0
± 0.2 Vp-p
s
Checking Location:
– BD BOARD (Conductor Side) –
114
2815
60
6180
4021
1
20
41
IC721
IC803
IC722
CN710
TP(RF)
TP(VC)