Read Sony CFD-44 Service Manual online
– 12 –
+
-
OSCILLOSCOPE
(DC range)
(DC range)
TP (TO)
TP (VC)
[CD MAIN BOARD] – Component side –
Adjustment Location : CD Main board (See page 14)
Focus Bias Adjustment
This adjustment is to be done when the optical pick-up block is re-
placed.
This adjustment is to be done when the optical pick-up block is re-
placed.
Adjustment procedure :
1.Connect oscilloscope to test point TP (VC) and TP (RF) on CD
MAIN BOARD.
2.Put the set into model.
3.Optical pic-up setting to the center by
3.Optical pic-up setting to the center by
+ or = button to
pushing.
4.Insert disc (YEDS-18) and press CD PLAY
· button.
5.Press CD PLAY
· button again.
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 (
A good eye pattern means that the diamond shape (
◊
) in the
center of the waveform can be clearly distinguished.
7.Release test mode after adjustment is completed.
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RF signal reference waveform (eye pattern)
1.1
±
0.2V
VOLT/DIV : 0.2V
TIME/DIV : 500ns
TIME/DIV : 500ns
When observing the eye pattern, set the oscilloscope for AC
range and raise vertical sensitivity.
range and raise vertical sensitivity.
+
-
OSCILLOSCOPE
(DC range)
(DC range)
TP (RF)
TP (VC)
[MAIN BOARD] – Component side –
Adjustment Location : CD Main board (See page 14)
Focus/Tracking Gain Adjustment
A frequency responce 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.
A frequency responce 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.
r
When gain is raised, the noise when the 2-axis device operates
increases.
increases.
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When gain is lowered, mechanical shock and skipping occurs
more easily.
more easily.
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When gain adjustment is off, the symptoms below appear.
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The time until music starts becomes
longer for STOP
→
·
PLAY or
automatic selection.
(
(
=, + buttons pressed.)
(Normally takes about 2 seconds.)
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Music does not start and disc
continues to rotate for STOP
→
·
PLAY or automatic selection.
(
=, + buttons pressed.)
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Sound is interrupted during PLAY.
Or time counter display stops
progressing.
progressing.
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More noise during 2-axis device
operation.
Symptoms
Gain
Focus
Tracking
low
low or high
–
low
–
low
high
high
The following is a simple adjustment method.
– Primary Adjustment –
Note :
Since exact adjustment cannot be performed, remember the
positions of the controls before performing the adjustment.If
the positions after the primary adjustment are only a little dif-
ferent, return the controls to the original position.
the positions after the primary adjustment are only a little dif-
ferent, return the controls to the original position.
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