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– 41 –

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

– 42 –

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.

Optical

Pick-up

BD Board

IC101, IC121

D101

IC171

¬

G

¬

¬

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) 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) (Note)

• 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 oscillo-
scope.
(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 6.)

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 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. Rotate the  AMS  knob and display “CREC MODE”. (S: 31)
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.
Note :
• Be careful not to apply vibration during continuous recording.

This unit uses two mechanism (Deck A) and (Deck B).
The decks can be operated individually.
For buttons or knobs not specified as Deck A or Deck B in the
procedure, use that of the corresponding deck.

1) When replacing the following parts, perform the adjustments

and checks with ¬ in the order shown in the following table.

– 43 –

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 8).

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

Checking Procedure:
1. Rotate the  AMS  knob to display “TEMP CHECK”.
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.)

KMS

260A

27X40
B0825

N

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

Ω

)

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  button
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, rotate the  AMS  knob and display “LDPWR CHECK”

(S: 2).

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.

Laser power meter reading : 7.0 ± 0.2 mW
Digital voltmeter reading : Optical pick-up displayed value ± 10%

(Optical pick-up label)

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.)

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

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. Rotate the  AMS  knob and display “EF MO CHECK”(S: 3).
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 rotate 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 rotate the  AMS  knob.
(Write power traverse checking)

(Traverse Waveform)

9. Press the  YES  button display “EFB = 

 MO-P”.

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

Note 1: 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.

Laser power
meter

Optical pick-up
objective lens

Digital volt meter

BD board

CN110 pin 

5

 (I+3V)

CN110 pin 

4

 (IOP)

VC

A

B

Specified value : Below 10% offset value

Offset value (%) =                  X 100  

I

A – BI

2 (A + B)

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

Oscilloscope

BD board

CN110 pin 

3

 (TEO)

CN110 pin 

1

 (VC)

VC

A

B

Specified value : Below 10% offset value

Offset value (%) =                  X 100  

I

A – BI

2 (A + B)

– 44 –

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

specified value is satisfied. Do not rotate 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. Roteto the  AMS  knob and display “EF CD CHECK” (S: 4).
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 rotate the  AMS  knob.

(Traverse Waveform)

17. Press the  YES  button and display “EF CD CHECK”.
18. Press the  §EJECT  button and remove the check disc (MD)

TDYS-1.

Note 1 : MO reading data will be erased during if a recorded disc is

used in this adjustment.

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

scope as shown in the following figure so that it can be
seen more clearly.

Change the focus bias and check the focus tolerance amount.
Checking Procedure :
1. Load a test disk (MDW-74/AU-1).
2. Rotate the  AMS  knob and display “CPLAY MODE” (S: 30).
3. Press the  YES  button twice and display “CPLAY MID”.
4. Press the  MENU/NO  button when “C = 

 AD = 

” is

displayed.

5. Rotate the  AMS  knob and display “FBIAS CHECK” (S: 5).
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 220 and ADER is below 2.

7. Press the  YES  button and display “ 

/

 b = 

”.

Check that the C1 error is below 220 and ADER is below 2.

8. Press the  YES  button and display “ 

/

 a = 

”.

Check that the C1 error is below 220 and ADER is below 2.

9. Press the  MENU/NO  button, next press the  §EJECT  button,

and remove the test disc.

Checking Procedure :
1. Load a test disk (MDW-74/AU-1).
2. Rotate the  AMS  knob and display “CPLAY MODE” (S: 30).
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 test disc.

Checking Procedure :
1. Load a check disc (MD) TDYS-1.
2. Rotate the  AMS  knob and display “CPLAY MODE” (S: 30).
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 the test 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. Rotate the  AMS  knob to display “CREC MODE” (S: 31).
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. Rotate the  AMS  knob to display “C PLAY MODE” (S: 30).
7. Press the  YES  button to display “C PLAY 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 remove the disc.

VC

A

B

Specified value : Below 10% offset value

Offset value (%) =                  X 100  

I

A – BI

2 (A + B)

VC

A

B

Specified value : Below 10% offset value

Offset value (%) =                  X 100  

I

A – BI

2 (A + B)

330 k

Ω

Oscilloscope

10pF

BD board

CN110 pin 

3

 (TEO)

CN110 pin 

1

 (VC)