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PD-S703
6. 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 Figure S.
@ Player state
Test mode, play
ment connections
50mV/division
20mV/division ee
YEDS-7
X- Y mode
[Procedure]
1. Set the AF generator output to 1.2 kHz and 2 Vp-p.
2. Press the TRACK/MANUAL SEARCH FWD [>> >] or REV KK <Kq key to move the pickup to halfway
across the disc (R=35 mm), then press the OUTPUT SELECTOR key, the PLAY [> key, then the PAUSE [][] key in
that order to close the corresponding servos and put the player into play mode.
3. Adjust VRI5S1 (TRK. GAN) so that the Lissajous waveform is symmetrical about the X axis and the Y axis.
Pin 3 (TRK. IN)
Pin 4 (GND)
0.001 LF
Bene eee nner rere et enaennnnenees 3
Low pass filter
Figure 5
Tracking Gain Adjustment
Higher gain
Optimum gain
Lower gain
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