Sony CFD-Z125 Service Manual page 21

E-F Balance Adjustment
This adjustment is to be done when the optical pick-up is replaced.
Procedure:
CD DECODER board
TP702 pin 1
TP702 pin 2
Connect the oscilloscope to TP702 pin 1 and pin 2 on the
1.
CD DECODER board.
2. Put the disc (YEDS-18).
3. Put the set into test mode. (See page 20.)
Press the ± and ≠ buttons to move the optical pick-up to
4.
the center.
Press the fl button.
5.
From focus searching, focus is turned ON while entering
CLV drawing-in mode. Tracking and sled are turned OFF.
6. Adjust VR702 so that the oscilloscope traverse waveform is
symmetrical, as shown in the figure below.
VOLT/DIV: 0.2V (with the 10:1 probe in use.)
TIME/DIV:1ms
0V
Adjustment value: 0.3 to 0.7Vp-p (A+B)
7. Release the test mode after adjustment is completed.
Adjustment Location: CD DECODER board (See page 22.)
oscilloscope
(DC range)
Note: Take long sweep time
for easy monitoring.
A
A=B 0V
B
A=B
Focus Bias Adjustment
This adjustment is to be done when the optical pick-up is replaced.
Procedure:
CD DECODER board
IC701 pin #¡
TP701 pin 2
1. Connect the oscilloscope IC701 pin #¡ and TP701 pin 2 on
the CD DECODER board.
2. Put the disc (YEDS-18.)
3. Put the set into test mode. (See page 20.)
4. Press ± and ≠ buttons to move the optical pick-up to the
center. (Move the optical pick-up to the music area on the disc
to enable easy visibility of the eye pattern.)
5. Press the fl button.
From focus searching, focus is turned ON while entering
CLV drawing-in mode. Tracking and sled are turned OFF.
6. Press the fl button.
[Both tracking and sled are turned ON.]
7. Adjust VR701 so that the 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.
A
• RF signal reference waveform (eye pattern)
B
VOLT/DIV : 0.2V (with the 10:1 probe in use.)
TIME/DIV : 500ns
When observing the eye pattern, set the oscilloscope for AC
range and raise vertical sensitivity.
8. Release the test mode after adjustment is completed.
Adjustment Location: CD DECODER board (See page 22.)
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oscilloscope
(AC range)
0.8 to 1.8Vp-p