Pioneer PD-41 서비스 매뉴얼 - 페이지 35

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Pioneer PD-41에 대해서도 마찬가지입니다: 사용 설명서 (28 페이지)

PD-41,PD-9700

8. Focus error signal(focus S curve)verification

@ Objective-

@ Symptom when out

of adjustment

To judge whether the pickup is O.K. or not by observing the focus error signal. The pickup is judged from

the amplitude of the tracking error signal (as discussed in the section on adjusting the tracking error

balance) and the wave form for the focus error signal.

aoe 2

@ Measurement instru-

ment connections

[Procedure]

Connect the oscilloscope to TP 1 Pin|

@ Player state

Test mode, stop

6 (FOCS ERR).

[Settings]

100 mV/division

@ Adjustment location | None

5 ms/division

DC mode

1. Connect TP 1 Pin 5 to ground.

2. Mount the disc.

3. While watching the oscilloscope screen, press the OUTPUT key and observe the waveform in Figure 8 for a moment.

Verify that the amplitude is at least 2.5 Vp-p and that the positive and negative amplitude are about equal. Since the

waveform is only output for a moment when the OUTPUT key is pressed, press this key over and over until you have

checked the waveform.

[Judging the pickup]

A=B

A+B22.5

Vp-p

Do not judge the pickup until all the adjustments have been made correctly. In the following cases, there may be

something wrong with the pickup.

1. The tracking error signal amplitude is extremely small (less than 2 Vp-p).

2. The focus error signal amplitude is extremely small (less than 2.5 Vp-p).

' 3. The positive and negative amplitudes of the focus error signal are extremely asymmetrical (2 : 1 ratio or more).

4. The RF signal is too small (less than 0.8 Vp-p) and even if VR 1 is adjusted (laser power), the RF signal can not be

brought up to the standard level.