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– 21 –

• 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 sled and spindle 
mechanisms. 
Other causes can be suspected.

– 22 –

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 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.

1. When replacing the following parts, perform the adjustments

and checks with 

¬ in the order shown in the following table.

pick-up

flexible board

laser tap

Optical

Pick-up

BD Board

IC101, IC121

D101

IC171

¬

G

¬

¬

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. 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.

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.

* 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. Turn the

= 

AMS

 

+ 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 

[     EJECT]

 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.

• Be careful not to apply vibration during continuous-recording.

§

– 23 –

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 Adjust-
ments” (See page 8).

When performing adjustments, set the internal temperature and
room temperature of 22 

°

C to 28 

°

C.

Checking Procedure:
1. Turn the

= 

AMS

 

+ knob to display “TEMP CHECK”

(C01).

2. Press the 

[YES]

 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

0  but-

ton or

) button to move the optical pick-up)

Connect the digital volt meter to CN110 pin 5 (I+3V) and
CN110 pin 4 (IOP).

2. Then, turn the

= 

AMS

 

+ knob and display “LDPWR

CHECK” (C02).

3. Press the 

[YES]

 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 

[YES]

 button once more and display “LD 7.0 mW $

”. Check that the reading the laser power meter and digital

volt meter satisfy the specified value.

Specification:
Laser power meter reading : 7.0 ± 0.2 mW
Digital voltmeter reading : Optical pick-up displayed value

±10%

5. Press the 

[MENU/NO]

 button and display “LDPWR CHECK”

and stop the laser emission.
(The 

[MENU/NO]

 button is effective at all times to stop the

laser emission)

Optical pick-up

objective lens

laser
power meter

+
–

BD board

digital voltmeter

CN110 pin 

5

 (I +3V)

CN110 pin 

4

 (IOP)

[      ]

[      ]

KMS260A

27X40
B0825

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

Ω

)

(Optical pick-up label)

After step 4, each time the 

[YES]

 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.

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

) button and move the optical pick-up outside

the pit.

4. Turn the

= 

AMS

 

+ knob and display “EF MO

CHECK”(C03).

5. Press the 

[YES]

 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 turn the

= 

AMS

 

+

knob.
(Read power traverse checking)

(Traverse Waveform)

7. Press the 

[YES]

 button and display “EFB = 

 MO-W”.

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

specified value is satisfied. Do not turn the

= 

AMS

 

+

knob.
(Write power traverse checking)

(Traverse Waveform)

+
–

oscilloscope

(DC range)

V: 0.1 V/div
H: 10 ms/div

BD board

CN110 pin 

3

 (TEO)

CN110 pin 

1

 (VC)

[      ]

A

B

VC

Specified value : Below 10% offset value

Offset value (%) =                  X 100  

I

A – B

I

2 (A + B)

A

B

VC

Specified value : Below 10% offset value

Offset value (%) =                  X 100  

I

A – B

I

2 (A + B)

+
–

oscilloscope

(DC range)

10 pF

330 k 

Ω

CN110 pin 

3

 (TEO)

CN110 pin 

1

 (VC)

BD board

Data will be erased during MO reading if a recorded disc is
used in this adjustment.

If the traverse waveform is not clear, connect the oscilloscope
as shown in the following figure so that it can be seen more
clearly.

– 24 –

9. Press the 

[YES]

 button display “EFB = 

 MO-P”.

Then, the optical pick-up moves to the pit area automatically
and servo is imposed.

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

specified value is satisfied. Do not turn the

= 

AMS

 

+

knob.

(Traverse Waveform)

11. Press the 

[YES]

 button display “EF MO CHECK”

The disc stops rotating automatically.

12. Press the 

[     EJECT]

 button and remove the disc.

13. Load the check disc (MD) TDYS-1.
14. Turn the

= 

AMS

 

+ knob and display “EF CD CHECK”

(C04).

15. Press the 

[YES]

 button and display “EFB = 

 CD”. Servo is

imposed automatically.

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

specified value is satisfied. Do not turn the  

= 

AMS

 

+

knob.

(Traverse Waveform)

17. Press the 

[YES]

 button and display “EF CD CHECK”.

18. Press the 

[     EJECT]

 button and take out the check disc.

A

B

VC

Specified value : Below 10% offset value

Offset value (%) =                  X 100  

I

A – B

I

2 (A + B)

§

A

B

VC

Specified value : Below 10% offset value

Offset value (%) =                  X 100  

I

A – B

I

2 (A + B)

§

Change the focus bias and check the focus tolerance amount.
Checking Procedure :
1. Load the test disk (MDW-74/AU-1).
2. Turn the

= 

AMS

 

+ knob and display “CPLAY MODE”

(C30).

3. Press the 

[YES]

 button twice and display “CPLAY MID”.

4. Press the 

[MENU/NO]

 button when “C = 

 AD = 

” is

displayed.

5. Turn the

= 

AMS

 

+ knob and display “FBIAS CHECK”

(C05).

6. Press the 

[YES]

 button and display “

/

 c = 

”.

The first four digits indicate the C1 error rate, the two digits
after [/] indicate ADER, and the 2 digits after [c =] indicate
the focus bias value.
Check that the C1 error is below 50 and ADER is below 2.

7. Press the 

[YES]

 button and display “

/

 b = 

”.

Check that the C1 error is about 200 and ADER is below 2.

8. Press the 

[YES]

 button and display “

/

 a = 

”.

Check that the C1 error is about 200 and ADER is below 2.

9. Press the 

[MENU/NO]

 button, next press the 

[     EJECT]

 but-

ton and take out the test disc.

Checking Procedure :
1. Load the test disk (MDW-74/AU-1).
2. Turn the

= 

AMS

 

+ knob and display “CPLAY MODE”

(C30).

3. Press the 

[YES]

 button and display “CPLAY MID”.

4. The display changes to “C = 

 AD = 

”.

5. If the C1 error rate is below 80, check that ADER is below 2.
6. Press the

[MENU/NO]

 button, stop playback, press the

[     EJECT]

 button and take out the test disc.

Checking Procedure :
1. Load the check disc (MD) TDYS-1.
2. Turn the

= 

AMS

 

+ knob and display “CPLAY MODE”

(C30).

3. Press the 

[YES]

 button twice and display “CPLAY MID”.

4. The display changes to “C = 

 AD = 

”.

5. Check that the C1 error rate is below 50.
6. Press the

[MENU/NO]

 button, stop playback, press the

[     EJECT]

 button and take out the check disc.

Prepare a continuous recording disc using the unit to be repaired
and check the error rate.

Checking Procedure :
1. Insert a recordable disc (blank disc) into the unit.
2. Turn the

= 

AMS

 

+ knob to display “CREC MODE”

(C31).

3. Press the 

[YES]

 button to display the “CREC MID”.

4. When recording starts, “  

  ” is displayed, this becomes

“CREC @@@@” (@@@@ is the address), and recording starts.

5. About 1 minute later, press the 

[MENU/NO]

 button to stop

continuous recording.

6. Turn the

= 

AMS

 

+ knob to display “CPLAY MODE”

(C30).

7. Press the 

[YES]

 button to display “CPLAY MID”.

8. “C = 

 AD = 

” will be displayed.

9. Check that the C1 error becomes below 80 and the AD error

below 2.

10. Press the 

[MENU/NO]

 button to stop playback, and press the

[     EJECT]

 button and take out the disc.

§

§

§

§