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DR- R504X
11. Tracking Servo Loop Gain Adjustment
(Adjustment
2)
•Objective
To optimize the tracking servo loop gain.
•Symptom when out of
Playback does not start, during searches the
actuator
is noisy,
or tracks are
skipped.
adjustment
•Measurement instru-
ment connections
[Procedure]
See Fig. 9.
[Settings]
CH I : 0.1 V/division
X-Y mode
CH 2 :10 mV/division
I.
Set
the AF generator output to l
.33kHz
and
2Vp-
p.
•Player state
Spindle rotation frequency
:
Normal
speed, focus ON, spindle
ON,
tracking ON
•Adjustment location
VR602 (TRK. GAIN)
•Disc
YEDS-7
2.
Move the pickup to midway
across
the disc (R=35mm). Spindle rotation frequency
:
Normal
speed,
focus
ON, spindle
ON and tracking ON put the player into play mode.
3.
Adjust
VR602
(TRK.
GAIN)
so
that
the
lissajous
waveform is symmetrical about
the
X axis and
the
Y
axis.
(10: 1)
Pin 3 (TRKIN)
Pin4 (AGND)
Pin 2
(TRKERR)
....................
-----··
....
.,
.
'
'
'
'
'
I
39kQ
I
i
0.001
µF
i
l
. . . . .
.
.
. . .
. . .
.
. . . . . . .
. .
.
7.f!..J
Low-pass filter
Fig.
9
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:·-······:·-··-···
r ····-··:·······t········
:
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·····r·······;-······
·· · • •: 1
1
1
1
·
·
·
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.....
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-
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~
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Highergain
Optimum gain
Lower gain
43
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