Sony MDS-JA333ES Service Manual page 28

5-2. Precautions for Checking Laser Diode
Emission
To check the emission of the laser diode during adjustments, never
view directly from the top as this may lose your eye-sight.
5-3. Precautions for Use of Optical Pick-up
(KMS-260B)
As the laser diode in the optical pick-up is easily damaged by static
electricity, solder the laser tap on the flexible board of the optical
pick-up when using it.
Before disconnecting the connector, disorder the laser tap. Be careful
not to remove the solder before connecting the connector. Also take
adequate measures to prevent damage by static electricity. Handle
the flexible board with care as it breaks easily.
Pick-up
Laser tap
Optical pick-up flexible board
5-4. Precautions for Adjustments
1) When replacing the following parts, perform the
adjustments and checks with !! in the order shown in the
following table.
Optical
pick-up
1. Initial setting of
a
adjustment value
2. Recording IOP
information
a
(the value that is
written in pick-up)
3. Temperature
×
compensation offset
adjustment
4. Laser power
a
adjustment
a
5. Traverse adjustment
6. Focus bias adjustment a
a
7. Error rate adjustment
8. Auto gain output
a
level adjustment
28
Flexible board
BD board
IC101,
IC171 D101 IC192
IC121
× ×
a a
× × ×
a
× ×
a a
×
a a a
× ×
a a
× ×
a a
× ×
a a
× ×
a a
2) Set the test mode when performing the adjustments.
After completing the adjustments, exit the test mode.
Perform the adjustments and checks in "Group S" of the test
mode.
3) Perform the necessary adjustments only in the order given.
4) Use the following tools and measuring devices.
• Check disc (MD) TDYS-1 (Parts No.: 4-963-646-01)
• Test disc (MDW-74/GA-1) (Parts No.: 4-229-747-01)
• Laser power meter LPM-8001 (Parts No.: J-2501-046-A)
Or
• MD laser power meter 8010S (Parts No.: J-2501-145-A)
(Note)
• Oscilloscope (Measure after perform the CAL of the probe.)
• Digital voltmeter
• Thermometer
• Tool for checking waveform of BD board (Parts No.: J-2501-
149-A)
5) When observing several signals on the oscilloscope, etc., make
sure that VC and ground do not connect inside the oscilloscope.
(VC and ground will become short-circuited.)
6 When checking the waveform, the check can be performed
without soldering by using the tool for checking waveform of
BD board.
(Refer to the Service note (page 7).)
7) Use the tool disc that is free from finger print and dust as they
can affect result of adjustment.
Note: Laser power meter
When the laser power check and adjustment of the electrical
adjustment are performed, using the new MD laser power meter
8010S (J-2501-145-A) instead of the former laser power meter is
recommended.
The procedure of installing the laser meter sensor to the objective
lens of pick-up is greatly simplified.