Sony MDS-JB940 Service Manual page 24

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 of the flexible board of the optical
pick-up when using it.
Before disconnecting the connector, desolder 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.
Pick-up
Optical pick-up flexible board
5-4. PRECAUTIONS FOR ADJUSTMENTS
1. When replacing the following parts, perform the adjustments
and checks with a in the order shown in the following table.
Optical
IC101
Pick-up
Initial setting of
×
a
adjustment value
Recording of
×
a
Iop information
TEMP
×
a
CHECK
Laser power
×
a
adjustment
×
a
Iop NV Save
Traverse
a a
adjustment
Focus bias
a a
adjustment
Auto gain
a a
adjustment
AUTO
a a
CHECK
2. Set the test mode when performing adjustments.
After completing the adjustments, release the test mode.
3. Perform only the adjustments to be needed in the order shown.
24
Flexible board
Laser tap
Replacement parts
IC102 IC151 IC190 IC195
× × ×
a
× × ×
a
× × ×
a
× ×
a a
×
a a a
× ×
a a
× ×
a a
× ×
a a
×
a a a
4. Use the following tools and measuring devices.
• Check Disc (MD) TDYS-1
(Part No. 4-963-646-01)
• Test Disc (MDW-74/GA-1) (Part No. 4-229-747-01)
• Laser power meter LPM-8001 (Part No. J-2501-046-A)
or
• MD Laser power meter 8010S (Part No. J-2501-145-A)
• Oscilloscope (Measure after performing CAL of prove)
• Digital voltmeter
• Thermometer
• Jig for checking BD board waveform
(Part No. : J-2501-196-A for MDM-7A)
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. Using the above jig enables the waveform to be checked without
the need to solder.
(Refer to Servicing Notes on page 6)
7. As the disc used will affect the adjustment results, make sure
that no dusts nor fingerprints are attached to it.
Laser power meter
When performing laser power checks and adjustment (electrical
adjustment), use of the new MD laser power meter 8010S (Part No.
J-2501-145-A) instead of the conventional laser power meter is
convenient.
It sharply reduces the time and trouble to set the laser power meter
sensor onto the objective lens of optical pick-up.
5-5. CREATING CONTINUOUSLY-RECORDED
DISC
* This disc is used in focus bias adjustment and MO error rate check.
The following describes how to create an MO continuous recording
D101
disc.
× 1. Insert a disc (MDW-74/GA-1)(blank disc) commercially
available.
Turn the l AMS L knob and display "CREC 1 MODE"
2.
×
(C35).
3. Press the YES button again to display "CREC 1 MID".
a
Display "CREC (0300)" and start to recording.
(Complete recording within 5 minutes.)
×
4. Press the MENU/NO button and stop recording .
5. Press the EJECT A button and remove the disc.
×
×
The above has been how to create a continuous recorded data for
the focus bias adjustment and MO error rate check.
× Note: Be careful not to apply vibration during continuous recording.
×
×