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DW - S114X
10. Focus Servo Loop Gain Adjustment
@ 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
@ Player state
Spindle rotation frequency : Normal
ment connections
speed, focus ON, spindle ON,
[Settings]
tracking ON
CH 1: 0.1 V/division
X= V mode
@ Adjustment location
{WR601 (FCS. GAIN)
CH 2 :20 mV/division
@ Disc
YEDS-7
[Procedure]
]. Set the AF generator output to 1.44kHz and 2Vp- p.
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.
TP201
(CN601)
Pin 5 (FCSIN) [O
Higher gain
Optimum gain
Lower gain
50
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