Pioneer PD-P920M Service Manual page 35

PD-Ps2o0NMl
8. Focus Error Signal (Focus S Curve) Verification
@ Symptom when out of
adjustment
e@ Measurement instru- | Connect the oscilloscope to @ Player state Test mode, stop
ment connections TP1, Pin 6 (FCS. ERR).
@ Adjustment location | None
[Settings] | 100 mV/division
5 ms/division
DC mode
@ Disc YEDS-7
[Procedure]
1. Connect TP1 Pin 5 to ground.
2. Mount the disc.
3. While watching the oscilloscope screen, press the PROGRAM 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 PROGRAM key is pressed, press this key over and over
until you have checked the waveform.
A
A=B
A+B 22.5Vp-p
B
Figure 8
[Judging the pickup]
Do not judge the pickup until all the adjustment 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 (Jess than 0.8 Vp-p) and even if VRI (laser power) is adjusted , the RF See can not be
brought up to the standard level.