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MD SECTION
6-1. PRECAUTIONS FOR CHECKING LASER DIODE
EMISSINON
When checking the emission of the laser diode during adjustments,
never view directly from the top as this may cause blindness.
6-2. 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 ad-
equate measures to prevent damage by static electricity. Handle the
flexible board with care as it breaks easily.
pick-up
Optical pick-up flexible board
6-3. PRECAUTIONS FOR ADJUSTMENTS
1) When replacing the following parts, perform adjustments and
checks marked ¬ in the order shown in the following table.
Optical
Pick-up
1. Temperature
G
compensation
offset adjustment
2. Laser power
¬
adjustment
3. Traverse
¬
adjustment
4. Focus bias
¬
adjustment
¬
5. Error rate check
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)
or
MD Laser power meter 8010S (Parts No. J-2501-145-A)
• Oscilloscope (Measure after calibration of the probe).
• Digital voltmeter
• Thermometer
5) When observing several signals on the oscilloscope, etc., make
sure that VC and ground do not connect inside the oscilloscope.
(The VC and ground will short-circuit.)
ELECTRICAL ADJUSTMENTS
flexible board
laser tap
BD Board
IC171
IC101, IC121, IC192
D101
¬
¬
¬
¬
G
¬
¬
G
¬
¬
G
¬
¬
G
¬
SECTION 6
Note : When performing laser power checks and adjustment
(electrical adjustment), use of the new MD laser power meter
8010S (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 the pick-up.
6-4. 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 VOLUME knob to display "CREC MODE".
3. Press the p (CD) button to display "CREC MID".
"CREC (0300)" will be momentarily displayed and recording
started.
4. Complete recording within 5 minutes.
5. Press the ^ (CD) button and stop recording .
6. Press the 6 (MD) 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.
6-5. TEMPERATURE COMPENSATION OFFSET
ADJUSTMENT
Save the current temperature data in the non-volatile memory as
the 25 °C standard data.
Notes:
1. Normally, this adjustment should not be preformed.
2. Set the surrounding temperature to 22 to 28 °C when performing
this adjustment.
Also perform this adjustment immediately after the power is
turned on when the internal temperature of the unit is the same
as the surrounding temperature (22 to 28 °C).
3. After replacing D101, perform this adjustment after the
temperature of parts reach the surrounding temperature.
Adjusting Procedure:
1. Rotate the VOLUME knob, to display "TEMP ADJUST".
2. Press the p (CD) button and select the "TEMP ADJUST" mode.
3. "TEMP=
4. To save the data: Press the p (CD) button.
If not saving the data: Press the ^ (CD) button.
5. When the p (CD) button is pressed, "TEMP=
displayed, and then "TEMP ADJUST" is displayed again.
"TEMP ADJUST" is displayed again immediately after the ^
(CD) button is pressed.
Specifications:
TEMP=
should be E0 to EF. F0 to FF, 00 to 0F, 10 to 1F and 20
to 2F.
– 24 –
" and the current temperature data are displayed.
SAVE" is
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