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25

• Perform the checks and adjustments of the MDM and MBU blocks following the procedure below .

The procedure is changed depending on the replaced part.

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

NG

Part Replacement and repairing

OWH is replaced ?

NO

Either OP, IC171, IC101, or 

IC121 is replaced ?

NO

YES

NO

YES

YES

NO

Initial setting of adjustment value

OP or IC171 is replaced ?

Either IC171 or D101 is replaced ?

Recording the IOP information

(IOP value that is recorded in OP)

Temperature compensation offset adjustment

• Traverse adjustment
• Focus bias adjustment
• Error rate adjustment
• Auto gain adjustment

OK

YES

The error occurs by other cause. 
Perform the mechanism check of 
the sled and spindle system, etc.

• Abbreviation
OP

: Optical pick-up

OWH : Overwrite head

26

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 on the flexible board of the optical
pick-up when using it.
Before disconnecting the connector, disorder the laser tap. Be careful
not to remove the solder before connecting the connector. 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.

Optical pick-up flexible board

Pick-up

Flexible board

Laser tap

2) Set the test mode when performing the adjustments.

After completing the adjustments, exit the test mode.
Perform the adjustments and checks in “Group S” of the test
mode.

3) Perform the necessary adjustments only in the order given.
4) Use the following tools and measuring devices.

• Check disc (MD) TDYS-1 (Parts No.: 4-963-646-01)
• Test disc (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)

• Oscilloscope (Measure after perform the CAL of the probe.)
• Digital voltmeter
• Thermometer
• Tool for checking waveform of BD board (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

When checking the waveform, the check can be performed
without soldering by using the tool for checking waveform of
BD board.
(Refer to the Service note (page 6).)

7) Use the tool disc that is free from finger print and dust as they

can affect result of adjustment.

Note: Laser power meter
When the laser power check and adjustment of the electrical
adjustment are performed, using the new MD laser power meter
8010S (J-2501-145-A) instead of the former laser power meter is
recommended.
The procedure of installing the laser meter sensor to the objective
lens of pickup is greatly simplified.

1. Initial setting of
adjustment value

2. Recording IOP

information
(the value that is
written in pick-up)

3. Temperature

compensation offset
adjustment

4. Laser power

adjustment

5. Traverse adjustment

6. Focus bias adjustment

7. Error rate adjustment

8. Auto gain output

level adjustment

a

a

×

a

a

a

a

a

D101

×

×

a

×
×
×
×

×

IC171

a

a

a

a

a

a

a

a

IC101,

IC121

a

×

×

a

a

a

a

a

IC192

×

×

×

a

×
×
×

×

27

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

The following describes how to create a continuos recording disc.

1. Load a disc (blank disc) commercially available.

the disc is loaded by pushing the tray.

2. Rotate the  lAMSL  knob and display “CREC MODE”

(C31).

3. Press the  YES  button to display “CMEC MID”.

“CREC (0300)” is displayed for a moment and recording starts.

4. Complete recording within 5 minutes.
5. Press the  MENU/NO  button to stop recording.
6. Press the A button to eject the disc.

The above has been how to create a continuos recording data for
the focus bias adjustment and error rate check.
Note:
• Be careful not to apply vibration during continuos recording.

This check aims at locating the approximate position of cause of
trouble before starting to replace parts using specifications.
For detailed information, refer to [Checks before Part Replacement
and Adjustment] of Service note (page 9).

Before adjustment, set the internal temperature and the ambient
temperature are between 22 and 28 

°

C.

Checking procedure:
1. Rotate the  lAMSL  knob to display “TEMP CHECK”

(C01).

2. Press the  YES  button.
3. It is OK when “T=@@(##)[OK” appears. It is NG when

“T=@@(##)[NG” appears. (@@ is the current value. ## is the
value that is written in the non-volatile memory.)

5-6-2. Laser Power Check
Before check:

• Refer to Section 1 “Service note” How to open the disc tray when

power switch is turned off, and laser power check.

• Check the IOP value of optical pick-up. (Refer to Section 5-8

“Recording and displaying IOP information”.)

Connection:

Checking procedure:

1. Insert the laser power meter from the disc inlet and set it on the

objective lens of the optical pick-up. (When it cannot be set
properly, press the  m  button and  M  button to move the
optical pick-up.)
Connect the digital voltmeter to CN110 5-pin (I+3V) and the
CN110 4-pin (IOP).

2. Rotate the  lAMSL  knob to display “LDPWR CHECK”

(C02).

3. Press the  YES  button once to display “LD 0.9mW $       ”.

Confirm that the reading of the laser power meter is 0.84 to
0.92 mW.

4. Press the  YES  button once again to display “LD 7.0mW $       ”.

Confirm that the readings of the laser power meter and digital
bolt meter satisfy the specified value.

Specification:
Laser power meter reading: 7.0 +/- 0.2 mW
Digital bolt meter reading: Optical pick-up displayed value +/- 10 %

5. Press the  MENU/NO  button to display “LDPWR CHECK”

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

: After step 4, the display of “LD 0.7mW$       ” “LD

6.2mW$      ”,  “LD WPcorrection $      ” is switched
every time when pressing the  YES  button. Operation
is not necessary for these displays.

Laser power meter

Optical pick-up

objective lens

Digital voltmeter

CN110 

5

-pin (I+3V)

 CN110 

4

-pin (IOP)

BD board

KMS

260B

24391

H0528

(For the checking procedure of
this value, refer to Section 5-8
 “Recording and displaying IOP information”.)

IOP = 52.8 mA in this case
IOP (mA) = digital bolt meter reading (mV)/1 (W)

 (Optical pick-up label)

28

Note 1 : If the recorded disc is used for this adjustment, the

  data is deleted.

Note 2 : If the traverse waveform is not clear, connect the

  oscilloscope as shown below so that it can be seen more
  clearly.

Connection:

Checking procedure:

1. Connect the oscilloscope to the CN110 3-pin (TEO) and the

CN110 1-pin (VC) of the BD board.

2. Load a recordable disc (any available on the market). (Refer to

Note 1.)
The disc is loaded by pushing the tray.

3. Press the  M  button to move the optical pick-up outside the

pit.

4. Rotate the  lAMSL  knob to display “EF MO CHECK”

(C03).

5. Press the  YES  button to display “EFB =       MO-R”.

(Laser power READ power, focus servo ON, tracking servo OFF,
and spindle (S) servo ON are set)

6. Observe the waveform of the oscilloscope and confirm it is

within the specified value. Do not rotate the  lAMSL
knob at that time.
(Read power traverse check)

7. Press the  YES  button to display “EFB =        MO-W”.

Oscilloscope (DC range)

 CN110 

3

-pin (TEO)

 CN110 

1

-pin (VC)

BD board

330k

Ω

10pF

Oscilloscope (DC range)

CN110 

3

-pin (TEO)

 CN110 

1

-pin (VC)

BD board

V : 0.5V/div  
H : 10ms/div

Specification: Offset value 10% or less

Offset value % =   



AB

   × 

100

(Traverse Waveform)

VC

 2(A+B)

A

B

8. Observe the waveform of the oscilloscope and confirm it that is

within the specified value. Do not rotate the  lAMSL
knob at this time.
(Write power traverse check)

9. Press the   YES  button to display “EFB =      MO-P”. The

optical pick-up moves to the internal circumference of the pit
area automatically and servo is imposed.

10. Observe the waveform of the oscilloscope and confirm that it is

within the specified value. Do not rotate the  lAMSL
knob at this time.

11. Press the   YES  button to display “EF MO CHECK”. The disc

stops rotating automatically.

12. Press the  A button to eject the disc.
13. Load the check disc (MD) TDYS-1.
14. Rotate the  lAMSL  knob to display “EF CD CHECK”

(04).

15. Press the  YES  button to display “EFB =        CD”. The servo is

imposed automatically.

16. Observe the waveform of the oscilloscope and confirm that it is

within the specified value. Do not rotate the  lAMSL
knob at this time.

17. Press the  YES  button to display “EF CD CHECK”.
18. Press the  A  button to eject the check disc (MD) TDYS-1.

Specification: Offset value 10% or less

Offset value % =   



AB

   × 

100

(Traverse Waveform)

VC

 2(A+B)

A

B

Specification: Offset value 10% or less

Offset value % =   



AB

   × 

100

(Traverse Waveform)

VC

 2(A+B)

A

B

Specification: Offset value 10% or less

Offset value % =   



AB

   × 

100

(Traverse Waveform)

VC

 2(A+B)

A

B