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DW - $114X
11. Tracking Servo Loop Gain Adjustment
@ 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
@Measurementinstru-
| See Fig. 9.
@ Player state
Spindle rotation frequency : Normal
ment connections
speed, focus ON, spindle ON,
[Settings]
tracking ON
CH 1 : 0.1 V/division
Wav mode
@ Adjustment location
| VR602 (TRK. GAIN)
CH 2 :10 mV/division
@ Disc
YEDS-7
[Procedure]
1. Set the AF generator output to 1.54kHz 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 VR602 (TRK. GAIN) so that the lissajous waveform is symmetrical about the X axis and the Y axis.
TP201
(CNB01) 99 KQ
Pin 3 (TRKIN) [O
Low-pass filter z
Higher gain
Optimum gain
~ Lower gain
51
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