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DW - $114X
8. Tracking Offset Adjustment
@ Objective
To correct for the variation in the sensitivity of the tracking photodiode.
@ Symptom when out of | Play does not start or track search is impossible.
adjustment
@ Measurement instru-
| Connect the oscilloscope to
@ Player state
ment connections
TP201
(CN601), Pin 2 (TE)
[This connection may be via a
low-pass filter
(39k Q +1000pF).]
@ Adjustment location
[Settings]
50 mV/division
5 ms/division
DC mode
[Procedure]
1. Move the pickup to midway across the disc (R=35mm).
2. Set to normal speed, focus ON and spindle ON.
Spindle rotation frequency : Normal
speed, focus ON, spindle ON/
tracking OFF
VR4 (TE. OFS)
3. Line up the bright line (ground) at the center of the oscilloscope screen and put the oscilloscope into DC mode.
4. Adjust VR4 (TE. OFS) so that the positive amplitude and negative amplitude of the tracking error signal at TP201
(CN601), Pin 2 (TE) are the same (in other words, so that there is no DC component).
Note : Perform the run-on adjustment in the section 7 and 8.
When there is a DC
When there is no DC
component
component
48
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