DHC-MD7, MDS-M9 - Sony Audio Service Manual (repair manual). Page 14

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

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.

1) When replacing the following parts, perform the adjustments and

checks with 

® in the order shown in the following table.

1. Temperature

compensation
offset adjustment

2. Laser power

adjustment

3. Traverse

adjustment

4. Focus bias

adjustment

Optical

Pick-up

BD Board

IC101, IC121, IC191

D101

IC171

®

G

®

®

®

G

®

®

®

®

®

G

G

G

G

®

®

®

®

®

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.

• MD test disc (CD) TDYS-1

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

• 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
oscilloscope.
(VC and Ground will become short-circuited.)

* This disc is used in focus bias adjustment and error rate check. The

following describes how to create a MO continuous recording disc.

1. Insert a MO disc (blank disc) commercially available.
2. Rotate the SELECTOR 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 EJECT 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.

5. Error rate check

laser tap