Sony HCD-EX6 Service Manual page 16

HCD-EX6/EX6T/EX8/EX8T/EX9/EX9T
Adjustment Location: Record/Playback Head
16
CD SECTION
Note:
1. CD Block is basically constructed to operate without adjustment.
2. Use YEDS-18 disc (Part No. 3-702-101-01) unless otherwise indicat-
ed.
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 specifi ed value with the following checks.
5. Check the focus bias check when optical pick-up block is replaced.
FOCUS BIAS CHECK
BD74 board
CL102 (RFOUT)
CL117 (VREF)
Procedure:
1. Connect the oscilloscope to CL102 (RFOUT) and CL117
(VREF) on the BD74 board.
2. Press the [ ] button to turn the power on, and press the
?/1
[FUNCTION] button to select CD function.
3. Set disc (YEDS-18) and press the [
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.
Checking Location:
– BD74 Board (Side B) –
CL117
(VREF)
IC301
CL102
(RFOUT)
IC101
oscilloscope
(DC range)
+
–
] button to playback.
u
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.1 ± 0.4 Vp-p