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SECTION 5
ELECTRICAL ADJUSTMENTS
5-1. PRECAUTIONS FOR CHECKING LASER DIODE
EMISSION
When checking the emission of the laser diode during adjustments,
never view directly from the top as this may cause blindness.
5-2. PRECAUTIONS FOR USE OF OPTICAL PICK-
UP (KMS-260A)
As the laser diode in the optical pick-up is easily damaged by static
electricity, solder the laser tap of the flexible board when using it.
Before disconnecting the connector, solder first. Before connecting
the connector, be careful not to remove the solder. Also take adequate
measures to prevent damage by static electricity. Handle the flexible
board with care as it breaks easily.
5-3. PRECAUTIONS FOR ADJUSTMENTS
1) When replacing the following parts, perform adjustments and
checks marked
¬
in the order shown in the following table.
Pick-up
Laser tap
Flexible board
Optical
Pick-up
BD Board
IC101, IC121, IC192
D101
IC171
¬
¬
G
¬
1. Temperature
compensation
offset
adjustment
2. Laser power
adjustment
3. Traverse
adjustment
4. Focus bias
adjustment
5. Error rate check
¬
G
¬
¬
¬
G
¬
¬
¬
G
¬
¬
¬
G
¬
¬
2) Perform the adjustment in the test mode.
After completing the adjustments, exit the test mode.
3) Perform the adjustments in the order shown.
4) Use the following tools and measuring devices.
• Check disc (MD) TDYS-1
(Parts No.:4-963-646-01)
• Laser power meter LPM-8001
(Parts No.:J-2501-046-A)
• Oscilloscope (Measure after calibration of the probe).
• Digital voltmeter
• Thermometer
• Jig for checking the BD board waveform
(Parts No.:J-2501-124-A)
5) When observing several signals on the oscilloscope, etc., make
sure that the VC and ground do not connect inside the
oscilloscope.
(The VC and ground will short-circuit.)
6) Using the above jig enables the waveform to be checked without
the need for soldering.
(Refer to Servicing Note on page 5.)
5-4. CREATING THE CONTINUOUSLY RECORDED
DISC
• The disc is used for the focus bias adjustment and error rate check.
The following describes how to create a continuously recorded
disc.
1. Insert a disc (blank disc) commercially available.
2. Rotate the AMS knob to display “CREC MODE”.
3. Press the YES button to display “CREC MID”.
“CREC (0300)” will be momentarily displayed and recording
started.
4. Complete recording within 5 minutes.
5. Press the NO button and stop recording.
6. Press the
§
button and remove the disc.
Create the continuous recorded disc for adjusting the focus bias
and checking the error rate as described above.
Note:
• Be careful not to apply vibrations during continuous recording.
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