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DR- R504X
1
O.
Focus Servo Loop Gain Adjustment
(Adjustment
2)
•Objective
To optimize the focus servo loop
gain.
•Symptom
when out of
Playback does not start or focus actuator
noisy.
adjustment
•Measurement instru-
See
Fig.
8
ment connections
[Procedure]
[Settings]
CH
I
:
0.1 V/division
X
-
Y
mode
CH 2 :IO mV/division
I.
Set the AF generator output to l .44kHz and I Vp
- p.
•Player
state
Spindle rotation frequency
:
Normal
speed, focus
ON,
spindle ON,
tracking ON
•Adjustment location
VR601
(FCS.
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 VR601 (FCS. GAIN) so that the lissajous waveform is symmetrical about the X axis and the Y
axis.
42
•
..
.
~
•.•
.
•
Highergain
.
•.
Pin 5 (FCSIN)
Pin 4 (AGND)
0
Pin
6
(FCSERR)
(10: 1)
(10
:
1)
~
Fig.
8
.
.
.
.
.
·ar·
Optimum gain
Lower
gain
(
(
(
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