Pioneer PD-Z84M Service Manual page 38

@ Symptom when out
of adjustment
[Settings] 100 mV //division @ Adjustment location | None
5 ms/division
DC mode
[Procedure]
1. Connect TP1 Pin 5 to ground.
2. Mount the disc.
3. While watching the oscilloscope screen, press the PGM key and observe the wave form 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 wave form is only output for a moment' when the PGM key is pressed, press this key over and over until you
have checked the wave form.
A
A=B
A+Bgz2.5 Vp-p
B
Figure 8
[Judging the pickup]
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 VR1 is adjusted (laser power), the RF signal can not be
brought up to the standard level.