Focus Offset Adjustment - Pioneer PD-J900M Service Manual

(How to play back a disc in test mode]
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In test mode, since the servos operate independently, playing back a disc requires that you operate the keys in the
correct order to close the servos.
Here is the key operation sequence for playing back a disc in test mode.
PROGRAM Lights up the laser diode and closes the focus servo.
4
PLAY/PAUSE [> /[l Starts the spindle motor and closes the spindle servo.
L
PLAY/PAUSE [> /Tl Closes the tracking servo.
(Press the [>/l] key twice)
Wait at least 2-3 seconds between each of these operations.
1. Focus Offset Adjustment
®@ Objective Sets the DC offset for the focus error amp.
@ Symptom when out of | The model does not focus in and the RF signal is dirty.
adjustment
@ Measurement instru- Connect the oscilloscope to @ Player state
ment connections TPI, Pin 6(FCS. ERR)
[Settings] 5 mV/division i ei
10 ms/division
[Procedure]
Test mode, stopped
(just the Power switch on)
VR103 (FCS. OFS)
None needed
Adjust VR103 (FCS. OFS) so that the DC voltage at TP1, Pin 6 (FCS. ERR) is — 150 + 50 mV.
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