– 9 –
1. Place the optical pick-up level, horizontally. (If the optical pick-
up is not level, the 2-axis device will be weighted and adjust-
ment cannot be done.)
2. Connect the oscilloscope between TP514 (TEO) and TP533 (VC)
on the MAIN board.
3. Set the disc (YEDS-18) and Press the
^
(
+
) key.
4. Turn RV502 slightly clockwise (tracking gain drops) and obtain
a waveform with a fundamental wave (waveform has large
waves) as in Figure 5-1 .
5. Turn RV502 slowly counterclockwise (tracking gain rises) until
the fundamental wave disappears (no large waves) as in Figure
5-2.
6. Set RV502 to the position about 30 °counterclockwise from the
position obtained in step 5. If RV502 contact point is more than
90 ° counterclockwise from mechanical center, tracking gain is
too high. In this case, readjust from step 4.
7. Press
^
(
+
) or
=
keys and observe the 100 track jump
waveform. Check that no traverse waveform appears for both
^
(
+
) or
=
directions. (See Figures 5-3 and 5-4.) It is
acceptable if the traverse waveform appears only now and then,
but if it appears constantly raise tracking gain slightly and check
step 7 again.
8. Check that there is no abnormal amount of operation noise (white
noise) from the 2-axis device. If there is, tracking gain is too
high, readjust starting with step 4.
The waveforms are those measured with the oscilloscope set as
shown below.
• VOLT/DIV : 50mV
• TIME/DIV : 5mS
• Waveform when tracking gain lowered.
Fundamental wave appears (large waves).
Fig. 5-1
• Waveform when fundamental wave disappears (no large waves).
Fig. 5-2
• Waveform when no traverse waveform during 100 track jump.
(Brake application is smooth because of adjustment.)
Fig. 5-3
• Waveform when no traverse waveform during 100 track jump.
(Brake application is poor because of adjustment.)
Fig. 5-4
0V
0V
0V
100 track jump waveform
0V
100 track jump
waveform
traverse waveform
Focus/Tracking Gain Adjustment
A servo 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 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 2-axis device operates in-
creases.
• When gain is lowered, it is more susceptible to mechanical shock
and skipping occurs more easily.
This adjustment has to be performed upon replacing any of the fol-
lowing parts :
• Optical pick-up
• RV503 (Focus gain)
• RV502 (Tracking gain)
Normally, be sure not to move RV503 (focus gain) and RV502
(tracking gain).
– Focus Gain Adjustment –
Procedure :
This adjustment is not performed. If focus gain RV503 is turned,
set to mechanical center
– Tracking Gain Adjustment –
(perform at normal operation)
[MAIN BOARD] (Side B)
1
5
10
15
18
19
25
30
36
37
40
45
50
54
55
60
65
70 72
C549
TP513(RFO)
R501
TP534
TP505
C599
R502
R503
TP502
R509
C806
R510
Q501
L502
C516
R506
R507
R505
TP503
TP504
TP506
TP547
TP509
TP510
TP511
TP508
TP517
TP518
TP519
C879
R809
P822
TP525
80
R806
TP514
(TEO)
TP521
R512 C501
7
TP532
TP501
TP522
TP533(VC)
TP555
TP821
TP507
TP512
TP523
IC801
X801
TP816
(TEST)
1
5
10
11
oscilloscope
(DC range)
TP514 (TEO)
TP533 (VC)
Содержание CD Walkman D-EG7
Страница 4: ... 4 SECTION 2 GENERAL This section is extracted from instruction manual ...
Страница 10: ... 10 Adjustment Location MAIN BOARD Side A RV503 Focus Gain Adjustment RV502 Tracking Gain Adjustment ...
Страница 13: ... 13 15 14 D EG5 EG5CK EG7 6 2 BLOCK DIAGRAM Signal path J CD ...
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