Fostex CR200 Service Manual page 29

4.3.11 Tracking Amp. Gain Adjustment
• Objective
• Symptom when out of adjustment
• Measurement instrument connections Oscilloscope to CN104, Pin-3 (TE) (HEAD BOARD assy)
• Disc
• Player state
• Adjustment location
[ Procedures ]
(1) Move the pickup to midway across the disc (R = 35mm) with the MANUAL /
TRACK SEARCH FWD or REV keys.
(2) Press the FINALIZE key and the PLAY key in the order to close the focus servo
and then the spindle servo.
(3) Line up the bright line (ground) at the center of the oscilloscope screen and put
the oscilloscope into DC mode.
(4) Adjust VR111 (TE. GAIN) so that the positive amplitude and negative amplitude
of the tracking error signal at CN104 (TP1), Pin 3 (TE) is 1.0V ± 0.05V.
4.3.12 Tracking Offset Adjustment
• Objective
• Symptom when out of adjustment
• Measurement instrument connections Oscilloscope to CN104, Pin-3 (TE) (HEAD BOARD assy)
• Disc
• Player state
• Adjustment location
[ Procedures ]
(1) Move the pickup to midway across the disc (R = 35mm) with the MANUAL / TRACK SEARCH FWD or REV keys.
(2) Press the FINALIZE key and the PLAY key in the order to close the focus servo and then the spindle servo.
(3) Line up the bright line (ground) at the center of the oscilloscope screen and put the oscilloscope into DC mode.
(4) Adjust VR112 (TE. OFS) so that the positive amplitude and negative amplitude of the tracking error signal at CN104,
Pin-3 (TE) are the same (in other words, so that there is no DC component).
Note : If the great offset is observed, perform the adjustments in the section 4.3.11 and 4.3.12.
To correct the discrepancy in the tracking error level with the pickup.
The unit does not playback, track search is impossible, tracks are skipped.
[The connection must be via a low pass filter (15k½ + 0.001µF). ]
GND probe can be connected to CN104, Pin-4 (AGND).
[ Settings ]: 20 mV/div., 5 mS/div.DC mode
TCD-785
Test mode, focus and spindle servos: closed, tracking servo: open
VR111 (TE. GAIN) (HEAD BOARD assy)
To correct for the variation in the sensitivity of the tracking photodiode.
The unit does not playback, track search is impossible, tracks are skipped.
[ This connection must be via a low pass filter (15k½ + 0.001µF).]
GND probe can be connected to CN104, Pin-4 (AGND).
[ Settings ]: 20 mV/div., 5 mS/div., DC mode
TCD-785
Test mode, focus and spindle servos: closed, tracking servo: open
VR112 (TE. OFS) (HEAD BOARD assy)
A = B
A
GND
B
When there is a DC
component
A = B
A
GND
B
When there is no DC
component
CR200
1.0V 0.05V
GND
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