Sony MDS-JB920 24, Precautions For Checking Laser Diode Emissinon, Precautions For Adjustments

2. PRECAUTIONS FOR CHECKING LASER DIODE EMISSINON

To check the emission of the laser diode during adjustments, never view directly from the top as this may lose your eye-sight.

3. 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, desolder first. Before con- necting 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 flexible board

laser tap

Optical pick-up flexible board

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			BD Board
	Pick-up	IC171	D101		IC101, IC121	IC192
1. Initial setting of	Â	Â	G		Â	G
adjustment value
2. Recording of IOP
information	Â	Â	G		G	G
(Value written in
the pick-up)
3. Temperature
compensation	G	Â	Â		G	G
offset adjustment
4. Laser power	Â	Â	G		Â	Â
adjustment
5. Traverse	Â	Â	G		Â	G
adjustment
6. Focus bias	Â	Â	G		Â	G
adjustment
7. Error rate check	Â	Â	G		Â	G
8. Auto gain output	Â	Â	G		Â	G
level adjustment

2.Set the test mode when performing adjustments. After completing the adjustments, exit the test mode. Perform the adjustments and checks in “group S” of the test mode.

3.Perform the adjustments to be needed in the order shown.

4.Use the following tools and measuring devices.

• Check Disc (MD) TDYS-1

(Parts No. 4-963-646-01)

•TEST DISK (MDW-74/AU-1) (Parts No. 8-892-341-41)

•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 performing CAL of prove.)

•Digital voltmeter

•Thermometer

•Jig for checking BD board waveform

(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 oscil- loscope.

(VC and ground will become short-circuited.)

6.Using the above jig enables the waveform to be checked with- out 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 (J-2501- 145-A) instead of the conventional laser power meter is conve- nient.

It sharply reduces the time and trouble to set the laser power meter sensor onto the objective lens of the pick-up.

5.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 disc (blank disc) commercially available.

2.Rotate the [ÊÊÊÊÊÊÊÊAMSÊÊÊÊÊÊÊÊ]- ± knob and display “CREC MODE”. (C31)

3.Press the [YES] button again to display “CREC MID”. Display “CREC (0300)” and start to recording.

4.Complete recording within 5 minutes.

5.Press the [MENU/NO] button and stop recording .

6.Press the [ÊÊÊÊÊEJECT]¤ button and remove the disc.

The above has been how to create a continuous recorded data for the focus bias adjustment and error rate check.

Note :

• Be careful not to apply vibration during continuous recording.

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