Sony CFD-CD777S Service Manual ▷ View online
– 17 –
Focus Tracking/Gain Adjustment
A frequency response analyzer is necessary in order to perform
this adjustment exactly.
However, this gain has a margin, so even if it is slightly off, there
is no problem. Therefore, do not perform this adjustment.
Focus Tracking/gain determines the pick-up follow-up (vertical
and horizontal) relative to mechanical noise and mechanical shock
when the 2-axis device operate.
However, as these reciprocate, the adjustment is at the point where
both are satisfied.
• When gain is raised, the noise when the 2-axis device operates
this adjustment exactly.
However, this gain has a margin, so even if it is slightly off, there
is no problem. Therefore, do not perform this adjustment.
Focus Tracking/gain determines the pick-up follow-up (vertical
and horizontal) relative to mechanical noise and mechanical shock
when the 2-axis device operate.
However, as these reciprocate, the adjustment is at the point where
both are satisfied.
• When gain is raised, the noise when the 2-axis device operates
increases.
• When gain is lowered, mechanical shock and skipping occurs
more easily.
• When gain adjustment is off, the symptoms below appear.
The following is a simple adjustment method.
– Primary Adjustment –
Note:
Since exact adjustment cannot be performed, remember the posi-
tions of the controls before performing the adjustment. If the posi-
tions after the primary adjustment are only a little different, return
the controls to the original position.
tions of the controls before performing the adjustment. If the posi-
tions after the primary adjustment are only a little different, return
the controls to the original position.
Connection:
• The time until music starts becomes longer for
STOP
→
^ button or automatic selection.
(
=, + buttons pressed.)
(Normally takes about 2 seconds.)
• Music does not start and disc continues to
rotate for STOP
→
^ button or automatic
selection.
(
(
=, + buttons pressed.)
• Sound is interrupted during PLAY.
Or time counter display stops progressing.
• More noise during 2-axis device operation
Gain
Focus
Tracking
Symptoms
low
low
or
high
–
low
–
low
high
high
+
–
–
Solder bridge (TRACKING)
Solder bridge (FOCUS)
TP (VC)
oscilloscope
(DC range)
Focus Bias Adjustment
This adjustment is to be done when the optical pick-up is replaced.
Procedure:
1. Connect the oscilloscope to solder bridge (FOCUS) and TP
(VC) on the MAIN board.
2. Put the set into test mode. (See page 24.)
3. Optical pick-up setting to the center by
3. Optical pick-up setting to the center by
+ or = button
pushing. (Move the optical pick-up to the music area on the
disc to enable easy visibility of the eye pattern.)
disc to enable easy visibility of the eye pattern.)
4. Put the disc (YEDS-18) and press
^ button.
From focus searching, focus is turned ON while entering
CLV drawing-in mode. Tracking and sled are turned OFF.
CLV drawing-in mode. Tracking and sled are turned OFF.
5. Press the
^ button.
[Both tracking and sled are turned ON.]
6. Adjust RV701 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 good eye pattern means that the diamond shape (≈) in the
center of the waveform can be clearly distinguished.
7. Release the test mode after adjustment is completed.
• RF signal reference waveform (eye pattern)
Adjustment Location: MAIN board (See page 19.)
+
–
–
MAIN board
Solder bridge (FOCUS)
TP (VC)
oscilloscope
(AC range)
VOLT/DIV: 0.2 V (with the 10: 1 probe in use.)
TIME/DIV: 500 ns
TIME/DIV: 500 ns
1.2
±
0.2 Vp-p
When observing the eye pattern, set the oscilloscope
for AC range and raise vertical sensitivity.
for AC range and raise vertical sensitivity.
– 18 –
Procedure:
1. Keep the set horizontal.
1. Keep the set horizontal.
If the set is not horizontal, this adjustment cannot be per-
formed due to the gravity against the 2-axis device.
formed due to the gravity against the 2-axis device.
2. Put the disc (YEDS-18) and press
^ button.
3. Connect the oscilloscope to solder bridge (FOCUS) and TP
(VC) on MAIN board.
4. Adjustment RV702 on MAIN board so that the waveform is
as shown in the figure below. (FOCUS gain adjustment)
• Incorrect Examples (DC level changes more than on adjusted
waveform)
)
(
VOLT/DIV: 100 mV
TIME/DIV: 2 ms
TIME/DIV: 2 ms
100 mV
0 V
VOLT/DIV: 100 mV
TIME/DIV: 2 ms
TIME/DIV: 2 ms
200 mV
0 V
VOLT/DIV: 100 mV
TIME/DIV: 2 ms
TIME/DIV: 2 ms
75 mV
0 V
low focus gain
high focus gain
5. Connect oscilloscope to solder bridge (TRACKING) and TP
(VC) on MAIN board.
6. Adjust RV704 on MAIN board so that the waveform is as
shown in the figure below. (Tracking gain adjustment)
VOLT/DIV: 1 V
TIME/DIV: 2 ms
TIME/DIV: 2 ms
0 V
• Incorrect Examples (fundamential wave appears)
VOLT/DIV: 1 V
TIME/DIV: 2 ms
TIME/DIV: 2 ms
0 V
VOLT/DIV: 1 V
TIME/DIV: 2 ms
TIME/DIV: 2 ms
0 V
low tracking gain
high tracking gain
high fandamential wave
than for low gain
high fandamential wave
than for low gain
)
(
– 19 –
Adjustment Location:
[MAIN Board] (Conductor Side)
[MAIN Board] (Component Side)
L3
IC703
RV704 Tracking Gain Adjustment
RV702 Focus Gain Adjustment
RV701 Focus Bias Adjustment
RV703 E-F Balance Adjustment
(FOCUS)
TP (VC)
(TRACKING)
IC701
– 20 –
SECTION 6
DIAGRAMS
• Circuit Boards Location
REMOTE CONTROL board
CONTROL board
SPEAKER board
MOTOR board
MAIN board
BATTERY
board
board
POWER board
FINE TUNING board
AMP board
RECORD/PLAYBACK SWITCH board
HEADPHONE board
LED
board
board
VOLUME board
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