DOWNLOAD Sony MDS-JB940 Service Manual ↓ Size: 12.66 MB | Pages: 74 in PDF or view online for FREE

21

N

X

SYNC (other models/TOC EDIT)

L. SYNC (other models/A.SPACE)

OVER

B/1 (REP portion)

A-REP

TRACK/(LP)4/calender frame

DISC/LP2

SLEEP/SHUF

MONO

Servo 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

Servo OFF

Tracking servo ON

Recording mode OFF

CLV normal mode

Tracking offset cancel OFF

Groove

Low reflection

CLV-A

CLV UNLOCK

This test mode automatically performs C-REC and C-PLAY and checks mainly the characteristics of the optical pick-up. To execute the test
mode, first check the laser power and perform AUTO CHECK after Iop Compare.

[Operation Procedure]
1.

Press the  YES  button. If “LDPWR 

 ” appears, which means the laser power has not been checked, first check the laser power and

perform Iop Compare. Then, repeat this step.

2.

If there is a disc in the mechanism deck, the disc is forcibly ejected.
After “DISC IN” appears, load a recordable test disc (MDW-74/GA-1).

3.

When the disc is loaded in step 2, the check automatically starts.

4.

While “XX CHECK” is displayed, the check of the item shown in “XX” is in progress.
After “06 check” is complete, eject the disc loaded in step 2. When “DISC IN” appears, load the TDYS-1 check disc (MD).

5.

After the disc loaded in step 4 is loaded, the check automatically restarts from “07 CHECK”.

6.

After the check of item 12 is complete, “OK” or “NG” appears. When all items are OK, “CHECK ALL OK” appears. If even one of the
items failed, “NG: xxxx” appears.

When “CHECK ALL OK” appears, there is no problem in the optical pick-up. Check the operations of the spindle motor, sled motor, etc.
If “NG: xxxx” appears, there is an abnormality in the optical pick-up. Replace the optical pick-up.

The version of the software is displayed.

[Operation Procedure]
1.

When “INFORMATION” appears, press the  YES  button.

2.

The version of the software is displayed.

3.

Press the  MENU/NO  button to end this mode.

If there is an abnormality in the data of the non-volatile memory, “E001” or “MEMORY NG” appears so that the MD mechanism deck does
not continue to be operated. If either of these messages appears, immediately enter the test mode and perform the following operation.

[Operation Procedure]
1.

Enter the test mode. (Refer to Section 4-2.)

2.

Normally, the test mode selection display appears. If there is an abnormality in the non-volatile memory, the message “INIT EEP?”
appears.

3.

Press the  x  button and the  EJECT A button at the same time.

4.

Turn the  l AMS L  knob to select “MDM-7A”.

5.

Press the  l AMS L  knob. After the non-volatile memory is rewritten, the mode returns to the normal test mode and the test mode
selection display appears.

22

If a defect such as dropout caused by the OP is found, check the following.

23

24

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 of the optical
pick-up 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 a in the order shown in the following table.

2.

Set the test mode when performing adjustments.
After completing the adjustments, release the test mode.

3.

Perform only the adjustments to be needed in the order shown.

Initial setting of
adjustment value

Recording of
Iop information

TEMP
CHECK

Laser power
adjustment

Iop NV Save

Traverse
adjustment

Focus bias
adjustment

Auto gain
adjustment

AUTO
CHECK

4.

Use the following tools and measuring devices.

• Check Disc (MD) TDYS-1

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

• Test Disc (MDW-74/GA-1) (Part No. 4-229-747-01)

• Laser power meter LPM-8001 (Part No. J-2501-046-A)

or

• MD Laser power meter 8010S (Part No. J-2501-145-A)

• Oscilloscope (Measure after performing CAL of prove)

• Digital voltmeter

• Thermometer

• Jig for checking BD board waveform

(Part No. : J-2501-196-A for MDM-7A)

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 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 (Part No.
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 optical pick-up.

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

The following describes how to create an MO continuous recording
disc.

1.

Insert a disc (MDW-74/GA-1)(blank disc) commercially
available.

2.

Turn the  l AMS L  knob and display “CREC 1 MODE”
(C35).

3.

Press the  YES  button again to display “CREC 1 MID”.
Display “CREC (0300)” and start to recording.
(Complete recording within 5 minutes.)

4.

Press the  MENU/NO  button and stop recording .

5.

Press the  EJECT A button and remove the disc.

The above has been how to create a continuous recorded data for
the focus bias adjustment and MO error rate check.

Be careful not to apply vibration during continuous recording.

a

a

×

a

a

a

a

a

a

×

×

a

×

×

a

a

a

a

×

×

×

×

a

×

×

×

×

×

×

×

×

×

a

a

a

a

×

×

×

a

a

×

×

×

a

a

a

a

a

a

a

a

a

a

×

×

a

×

×

×

×

×

×