Pioneer PD-41 Service Manual page 34

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PD-41,

PD-9700

7. Tracking servo loop gain adjustment

@ Objective

To optimize the tracking servo loop gain

@ Symptom

wh::: out} Playback does not start, during searches the actuator is noisy, or tracks are skipped.

of adjustment

@ Measurement instru- | See Figure 7.

@ Player state

ment connections

Test mode, play

[Settings]

CH1

CH 2

@ Adjustment location} VR 151 (TRK GAN)

50 mV/division

X-Y mode

@ Disc

YEDS-7

[Procedure]

1. Set the AF generator output to 1.2kHz and 1 Vp-p.

2. Press the TRACK FWD DX or REV KK key to move the pickup to halfway across the disc (R = 35 mm), then press the

OUTPUT 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 VR 151 (TRK GAN) so that the Lissajous wave form is symmetrical about the X axis and the Y axis.

3PIN

(TRK IN)

4P1IN

(GND)

(TRK ERR)

39K 2

7 0.001 x F }

Low pass filter

Figure 7

Tracking Gain Adjustment

Higher gain

Optimum gain

Lower gain

Pd-9700