DOWNLOAD Sony CMT-DC500MD / HCD-J300 Service Manual ↓ Size: 17.2 MB | Pages: 93 in PDF or view online for FREE

29

Note :

1. CD Block is basically designed to operate without adjustment.

Therefore, check each item in order given.

2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10M

Ω

 impedance.

4. Clean the object lens by an applicator with neutral detergent

when the signal level is low than specified value with the
following checks.

Procedure :
1. Connect oscilloscope to TP (RFAC).
2. Turned Power switch on.
3. Load a disc (YEDS-18) and playback.
4. Confirm that oscilloscope waveform is clear and check RF signal

level is correct or not.

Note: Clear RF signal waveform means that the shape “

◊

” can be

clearly distinguished at the center of the waveform.

Procedure:
1.

Connect oscilloscope to TP (TE) and TP (DVC 1.65V).

2.

Turned Power switch on.

3.

Load a disc (YEDS-18) and playback the number five track.

4.

Press the  u  button. (Becomes the 1track jump mode.)

5.

Confirm that the level B and A (DC voltage) on the oscilloscope
waveform.

Specification level:      x 100=less than ±22%

TP(RFAC)

TP(DVC 1.65V)

CD BOARD

oscilloscope

VOLT/DIV : 200mV
TIME/DIV : 500ns

level : 1.1 

±

 0.3Vp-p 

CD BOARD

Oscilloscope

TP(TE)

TP(DVC 1.65V)

0V

Center of
waveform

B

Symmetry

A (DC voltage)

level=1.3 

±

0.6Vp-p

A
B

Procedure :
1.

Connect frequency counter to TP (XPCK) with lead wire.

2.

Turned Power switch on.

3.

Put the disc (YEDS-18) in to play the number five track.
Confirm that reading on frequency counter is 4.3218MHz.

+
–

frequency counter

CD BOARD

TP (XPCK)

TP
(DVC 1.65V)

TP
(TE)

IC101

IC103

TP 
(XPCK)

TP 
(RFAC)

30

Other faults are suspected.
Check the mechanism parts (spindle motor, sled motor, etc.).

Start

NG

NG

NG

OK

OK

OK

Laser Power Check

6-2.

(See page 32)

6-3.

(See page 32)

6-4.

(See page 33)

Iop Compare

Auto Check

Replace optical pick-up or MDM-7B

Note 1: About “R”

As this unit has only a few buttons, some operations require the use of remote commander (RM-SDC500/provided with unit: 1-476-756-11)
buttons. These operations are indicated as “R” in this manual.
Example:

MENU/NO “R”

...Press the 

[MENU/NO]

 button of the remote commander.

Note 2: Incorrect operations may be performed if the MD test mode is not entered properly.

In this case, press the

?/1

button to turn the power off, and retry to enter the MD test mode.

If malfunctions caused by optical pick-up such as sound skipping are suspected, follow the following check.

31

To c hec k the emission of the laser diode during adjustments,

 ne ver

vie w directl y from the top as this ma

y lose y our e ye-sight.

As the laser diode in the optical pick-up is easily damaged by static
electricity , solder the laser tap of the fle

xib le boar d when using it.

Before disconnecting the connector

, desolder fir st.  Before connecting

the connector

, be careful not to remo

ve the solder

. Also take adequate

measures to pre

vent dama ge b y static electricity

. Handle the fle xible

boar d with care as it breaks easil

y.

1.

When replacing the f

ollo wing par ts,  perf orm the adjustments

and c hec ks with 

 in the or der sho wn in the f ollo wing tab le.

2.

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

 exit the MD test mode

.

Perform the adjustments and checks in “Group Service” of the
MD test mode.

3.

Perform the adjustments to be needed in the or

der sho wn.

4.

Use the f ollo wing tools and measuring de

vices.

•

Chec k Disc (TD YS-1) (P ar t No.  : 4-963-646-01)

•

Test Disk (MD W-74/GA-1) (P ar t No.  : 4-229-747-01)

•

Laser po wer meter LPM-8001 (P

ar t No.  : J-2501-046-A)

or
MD Laser po wer meter 8010S (P

ar t No.  :  J-2501-145-A)*

1

• Oscilloscope (Measure after perf

orming CAL of pr ove .)

• Digital v oltmeter
• Thermometer
• Jig f or c hec king BD boar d wa veform

(Par t No.  : J-2501-196-A)

pick-up

flexible board

laser tap

5.

When obser ving se veral signals on the oscilloscope

, etc.,

make sure that 

VC and gr ound do not connect inside the

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

6.

Using the abo

ve jig enab les the wa veform to be c hec ked without

the need to solder

.

(Refer to Servicing Notes on page 8.)

7.

As the disc used will aff

ect the adjustment results,

 make sure

that no dusts nor fing

erprints are attac

hed to it.

*

1

When perf orming laser po

wer c hec ks and adjustment (electrical

adjustment),  use of the ne

w MD laser po wer meter 8010S (P

ar t

No. J-2501-145-A) instead of the con

ventional laser po

wer

meter is con venient.
It sharpl y reduces the time and tr

oub le to set the laser po

wer

meter sensor onto the objective lens of optical pic

k-up.

7.

Initial setting of adjustment value

8.

Recording of Iop information

9.

Temperature compensation

offset adjustment

10. Laser power adjustment

11. Iop NV Save

12. Traverse adjustment

13. Focus bias adjustment

16. Auto gain adjustment

6-4. AUTO CHECK

Optical

Pick-up

IC101

IC102

IC151

IC190

IC195

D101

Parts to be replaced

Adjustment

32

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
in MD” (see page 26).

6-1. Temperature Compensation Offset Check
When performing adjustments, set the internal temperature and room
temperature to 22 to 28ºC.

Procedure:
1. Press the

.  “R”

or

>  “R”

button to display “TEMP

CHECK” (C12).

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.)

6-2. Laser Power Check
Before starting adjustment;
The laser power adjustment value changes depending upon the types
of the optical pick-up (KMS-260B or KMS-260E).
Check the type of the optical pick-up before starting adjustment.
(See the illustrations “The method of ideutifying the optical pick-
up” on page 36)
Before checking, check the Iop value of the optical pick-up.
(Refer to 8. Recording and Displaying the Iop Information (see page
35)

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

pick-up. (When it cannot be set properly, press the  m

 “R”

  button

or  M

“R”

  button to move the optical pick-up.)

Connect the digital volt meter to CN105 pin 1 (I+3V) and
CN105 pin 2 (IOP).

2. Then, press the

.“R”

or

>“R”

button and display

“LDPWR CHECK” (C13).

3. Press the

ENTER/YES “R”

button once and display “LD

0.9mW$

”. Check that the reading of the laser power meter

becomes specified value.

4. Press the

ENTER/YES “R”

button once more and display “ LD

8.4mW$

”. Check that the reading the laser power meter and

digital volt meter satisfy the specified value.

Specified Value:
Laser power meter reading :

Digital voltmeter reading : Optical pick-up displayed value ± 10%

5. Press the

MENU/NO “R”

button and display “LDPWR CHECK”

(C13) and stop the laser emission.
(The

MENU/NO “R”

button is effective at all times to stop the

laser emission.)

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

display will be switched to “LD 0.7W$

”and “LD 7.5mW$

”

“LD WP 

 $

”. Nothing needs to be performed here.

Checking Location: BD board (see page 39)

6-3. Iop Compare
The current Iop value at laser power 8.4 mW output and reference
Iop value (set at shipment) written in the nonvolatile memory are
compared, and the rate of increase/decrease will be displayed in
percentage.

Note: Perform this function with the optical pick-up set at room tempera-

ture.

Procedure:
1. Press the

.“R”

or

> “R”

button to display “Iop Compare”

(C27).

2. Press the

ENTER/YES “R”

button and start measurements.

3. When measurements complete, the display changes to “± xx%

yy”.
xx is the percentage of increase/decrease, and OK or NG is
displayed at yy to indicate whether the percentage of increase/
decrease is within the allowable range.

4. Press the

MENU/NO “R”

button to end.

* 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

. “R”

or

>  “R”

button and display “CREC  1MODE”

(C35).

3. Press the

ENTER/YES  “R”

button again to display “CREC 1

MID”.
Display “CREC 1(0300)” and start to recording.

4. Complete recording within 5 minutes.
5. Press the

MENU/NO “R”

button and stop recording .

6. Press the Z (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.

Optical pick-up
objective lens

laser
power meter

+
–

BD board

digital voltmeter

CN105 pin 

1

 (I+3V)

CN105 pin 

2

 (IOP)

KMS260B

20101

H0576

lOP=57.6 mA in this case
lOP (mA) = Digital voltmeter reading (mV)/1 (

Ω

)

(Optical pick-up label)

For details of the method for
checking this value, refer to 
“8. Recording and Displaying
the Iop Information”

SPECIFIED VALUE

KMS-260B
KMS-260E

0.85 to 0.91 mW
0.90 to 0.96 mW

KMS-260B
KMS-260E

6.8 to 7.2 mW
7.0 to 7.5 mW