Electrical Adjustments; Md Section - Sony HCD-MD1EX - System Service Manual

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 connect-
ing 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
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 (MD) Board
IC171 D101 IC101, IC121, IC192
¬ ¬ ¬
¬ 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.
[VOLUME+/–]
2. Press the
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 sur-
rounding temperature (22 to 28 °C).
3. After replacing D101, perform this adjustment after the temperature
of parts reach the surrounding temperature.
Adjusting Procedure:
[VOLUME+/–]
1. Press the
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.
– 26 –
button to display "CREC MODE".
button, to display "TEMP ADJUST".
" and the current temperature data are displayed.
SAVE" is