Electrical Adjustments - Sony MDS-JA50ES Service Manual

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.
Precautions for Use of optical pick-up (KMS-210A)
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, desolder 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.
Optical pick-up flexible board
• Abbreviation
MO: Recordable disc
CD: Disc for playback only
SECTION 5

ELECTRICAL ADJUSTMENTS

laser tap
— 32 —
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. Temperature
compensation
G
offset adjustment
2. Laser power
¬
adjustment
3. Traverse
¬
adjustment
4. Focus bias
¬
adjustment
5. Error rate check
¬
2) Set the test mode when performing adjustments.
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
• Laser power meter LPM-8001 (Parts No. J-2501-046-A)
• Oscilloscope
• Digital voltmeter
• Thermometer
5) When observing several signals on the oscilloscope, etc.,
make sure that VC and ground do not connect inside the oscillo-
scope.
(VC and ground will become short-circuited.)
Creating Continuously Recorded Disc
* This disc is used in focus bias adjustment and error rate check.
The following describes how to create a continuous recording disc.
1. Insert a MO disc (blank disc) commercially available.
2. Rotate the AMS knob and display "CREC MODE".
3. Press the YES button and display "CREC IN".
4. Press the YES button again to display "CREC MID".
"CREC (0300" is displayed for a moment and recording starts.
5. Complete recording within 5 minutes.
6. Press the NO button and stop recording .
7. Press the §OPEN/CLOSE button and remove the MO disc.
The above has been how to create a continuous recording data for
the focus bias adjustment and error rate check.
Note :
• Be careful not to apply vibration during continuous recording.
BD Board
IC171 D101 IC101, IC121, IC191
¬ ¬ ¬
¬
G G
¬
¬ G
¬ G ¬
¬ G ¬
(Parts No. 4-963-646-01)