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7. Tracking Servo Loop Gain Adjustment
ae
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-
| See Figure 7.
@ Player state
Test mode, piay
ment connections
[Settings]
@ Adjustment location - | VRIS1 (TRK. GAN)
CH1
CH2
50mV/division
50 mV/division
X-Y mode
[Procedure]
Disc
YEDS-7
1. Set the AF generator output to 1.2 kHz and 2 Vp-p.
2. Press the MANUAL SEARCH FWD b>-or REV <i key to move the pickup to halfway across the disc (R=35 mm),
then press the PROGRAM key, the PLAY: > key, then the PAUSE 8 key in that order to close the corresponding
servos and put the player into play mode.
3. Adjust VR151 (TRK. GAN) so that the Lissajous waveform is symmetrical about the X axis and the Y axis.
Pin 3 (TRK. IN)
Pin 4 (GND)
Pin 2 (TRK. ERR)
0.001 pF
Low pass fitter
Figure 7
Tracking Gain Adjustment
iil
Higher gain
Optimum gain
Lower gain
48
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