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33

MD

7

 (green)*

MD

7

 (orange)*

z

 MD*

SYNC

LEVEL-SYNC

OVER

1

REPEAT

TRACK

DISC

SHUFFLE

MONO

During continuous playback (CLV: ON)

Tracking servo OFF

Recording mode ON

CLV low speed mode

ABCD adjustment completed

Tracking offset cancel ON

Tracking auto gain OK

Focus auto gain OK

Pit

High reflection

CLV S

CLV LOCK

STOP (CLV: OFF)

Tracking servo ON

Recording mode OFF

CLV normal mode

Tracking offset cancel OFF

Groove

Low reflection

CLV A

CLV UNLOCK

* Items shown correspond to the indicated button indicators.

34

• Check and adjust the MDM and MBU as follows.

The procedure changes according to the part replaced

• Abbreviation

OP

: Optical pick-up

OWH: Overwrite head

• Temperature compensation offset check
• Laser power check
• Traverse check
• Focus bias check
• C PLAY check
• Self-recording/playback check

Parts Replacement and Repair

NG

Has the OWH been replaced?

NO

OK

NO

NO

NO

Has OP, IC171, IC101, or 
IC121 been replaced?

YES

YES

Initial setting of the adjustment value

Has OP or IC171 been replaced?

YES

IOP information recording
(IOP value labeled on OP)

Has IC171 or D101 
been replaced?

YES

Temperature compensation offset adjustment

• Laser power adjustment
• Traverse adjustment
• Focus bias adjustment
• Error rate adjustment
• Focus bias check
• Auto gain adjustment

Check the sledding and spindle 
mechanisms. 
Other causes can be suspected.

35

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 connecting
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.

IC101, IC121

D101

IC171

¬

G

¬

¬

optical pick-up

flexible board

laser tap

1. Initial setting of

adjustment value

2. Recording of IOP

information
(Value written in
the pick-up)

3. Temperature

compensation
offset adjustment

4. Laser power

adjustment

5. Traverse

adjustment

6. Focus bias

adjustment

7. Error rate check

8. Auto gain output

level adjustment

IC192

G

¬

G

¬

G

G

¬

¬

G

G

G

¬

G

¬

¬

¬

¬

G

¬

¬

G

¬

G

¬

¬

G

¬

G

¬

¬

G

¬

G

¬

¬

G

2)

Enter 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) NOTE 1:

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

6)

Using the above jig enables the waveform to be checked without
the need to solder.
(Refer to Servicing Note on page 11.)

7)

As the disc used will affect the adjustment results, make sure
that no dusts nor fingerprints are attached to it.

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 optical pick-up.

* 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.

Press the lm/TUNING –  button or ML/TUNING
+ button and display “CREC MODE”.

3.

Press the  ENTER/YES “R”  button again to display “CREC
MID”.
Display “CREC (0300)” and start to recording.

4.

Complete recording within 5 minutes.

5.

Press the  MENU/NO “R”  button and stop recording .

6.

Press the  A (MD)  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.

Note 1: About “R”
As this unit has only a few buttons, some operations require the
use  of  remote  commander  (RM-SJ373/provided  with  unit:
1-418-554-11) buttons. These operations are indicated as  “R”
in this manual.
Example:  MENU/NO “R”  ...Press the MENU/NO button of
the remote commander.

36

KMS

260A

27X40
B0825

N

Iop = 82.5 mA in this case
Iop (mA) = Digital voltmeter reading (mV)/1 (

Ω

)

(For details of the method for checking
this value, refer to “5-8. Recording and
Displaying IOP Information”.)

Laser power
meter

Optical pick-up
objective lens

Digital voltmeter

BD (MD) board

CN110 pin 

5

 (I+3V)

CN110 pin 

4

 (IOP)

V : 0.5 V/div
H : 10 ms/div
Input : DC mode

Oscilloscope

BD (MD) board

CN110 pin 

3

 (TE)

CN110 pin 

1

 (VC)

VC

A

B

Specified value : 10% or less of the offset value

Offset value (%) =                  X 100  

I

A – BI

2 (A + B)

VC

A

B

Specified value : 10% or less of the offset value

Offset value (%) =                  X 100  

I

A – BI

2 (A + B)

These checks are performed before replacing parts according to
“approximate specifications” to determine the faulty locations. For
details, refer to “Checks Prior to Parts Replacement and
Adjustments” (See page 14).

When performing adjustments, set the internal temperature and room
temperature to 22 to 28

°

C.

Checking Procedure:
1. Press the  lm/TUNING – button or  ML/TUNING +

button to display “TEMP CHECK”.

2. Press the  ENTER/YES “R”  button.
3. “T=@@(##) [OK]” should be displayed. If “T=@@ (##) [NG]”

is displayed, it means that the results are bad.
(@@ indicates the current value set, and ## indicates the value
written in the non-volatile memory.)

Before checking, check the IOP value of the optical pick-up.
(Refer to “5-8. Recording and Displaying IOP Information”.)

Checking Procedure:
1. Set the laser power meter on the objective lens of the optical

pick-up. (When it cannot be set properly, press the  lm/
TUNING –  button or  ML/TUNING +  button continuously
to move the optical pick-up.)
Connect the digital volt meter to CN110 pin 5  (I+3V) and
CN110 pin 4 (IOP).

2. Then, press the  lm/TUNING –  button or  ML/

TUNING +  button and display “LDPWR CHECK”.

3. Press the  ENTER/YES “R”  button once and display “LD 0.9

mW $ 

”. Check that the reading of the laser power meter

become 0.84 to 0.92 mW.

4. Press the  ENTER/YES “R”  button once more and display “LD

7.0 mW $ 

”. Check that the reading of the laser power meter

and digital volt meter satisfy the specified value.

Laser power meter reading : 7.0 

±

 0.2 mW

Digital voltmeter reading : Optical pick-up displayed value 

±

 10%

(Optical pick-up label)

Checking Procedure:
1. Connect an oscilloscope to CN110 pin 3 (TE) and CN110 pin

1

 (VC) of the BD board.

2. Load a disc (any available on the market). (Refer to Note 1.)
3. Press the  ML/TUNING +  button continuously and move

the optical pick-up outside the pit.

4. Press the lm/TUNING –  button or  ML/TUNING +

button and display “EF MO CHECK”.

5. Press the  ENTER/YES “R”  button and display “EFB = 

 MO-

R”.
(Laser power READ power/Focus servo ON/tracking servo OFF/
spindle (S) servo ON)

6. Observe the waveform of the oscilloscope, and check that the

specified value is satisfied. Do not press the  lm/TUNING
–  button or  ML/TUNING + button.
(Read power traverse checking)

(Traverse Waveform)

7. Press the  ENTER/YES “R”  button and display “EFB = 

 MO-

W”.

8. Observe the waveform of the oscilloscope, and check that the

specified value is satisfied.  Do not press the  lm/TUNING
–  button or  ML/TUNING +  button.
(Write power traverse checking)

(Traverse Waveform)

5.

Press the  MENU/NO “R”  button and display “LDPWR
CHECK” and stop the laser emission.

(The  MENU/NO “R”  button is effective at all times to stop the
laser emission.)

Note 1: After step 4, each time the  ENTER/YES “R”  button is

pressed, the display will be switched between “LD 0.7 mW
$ 

”, “LD 6.2 mW $ 

”, and “LD WP                $ 

”.

Nothing needs to be performed here.