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The pickup unit reads signals from the disk, and the flexible cable is connected to the board. The following signals flow through the
cable.

FO+

TR–

TR+

FO–

ACTUATOR

OSC

V

OS

LD

PD

VA

VB

VC

VD

Sga

V

raf

V

cc

GND

–
+
–
+
–
+
–
+

HOLOGRAM LASER UNIT

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

1

TR–

FO+

TR+

FO–

VR

PD

V

CC

GND

LD

GND

V

OS

NC

NC

V

ref

(VCC/2)

VA

VC

Sga

GND

VB

VD

(NC)

Power adjust

HIGH-FREQUENCY CONVOLUTION

Focus

When electric current is flowed

FO+, FO-

from FO+ to FO-, the lens comes
 to near the disk.

Tracking

When electric current is flowed

TR+, TR-

from TR+ to TR-, the lens goes
toward the outer circumference.

Gain switching DVD one Layer

High gain

Sga

DVD two Layer

Sga : +5V

         CD

8-4-1. Tracking drive signal (TR+, TR-)
The signal drives the tracking servo mechanism which projects the beam on the track by moving the objective lens (OL) to the outer
or inner circumference (at a right angle against the track) of the disk.

8-4-2. Focus drive signal (FO+, FO-)
The signal drives the focus servo mechanism which aligns the focus on the pit of the disk
by elevating OL (vertically against the disk surface.)

The VR terminal is connected to GND.

2-focus objective lens

Actuator assembly

8-4-3. Monitor Diode (PD)
Since the laser diode largely varies output of the laser light even if the flowing current is slightly varied, the projection
light is detected with the monitor diode to control the laser light to be equally output.
Since the current varies on the monitor diode according to the intensity of the received light of the laser diode, the drive current of
the laser diode is reduced if the current of the monitor diode increases. On the contrary, the drive current of the laser diode is increased
if the current of the monitor diode decreases.
As the projection light of the laser diode becomes stronger, the current of the monitor diode increases to increase the current which
flows into the monitor diode output (PD).  This is input to the pin 44 of IC303 and is compared with the reference voltage to control
the drive current of the laser diode.
The circuit is called ALPC (Automatic Laser Power Control).

8-4-4. Laser diode drive current control (LD)
Power supply to drive the laser diode

8-4-5. High-frequency convolution module power supply (VOSC)
The high-frequency convolution imposes the high-frequency signal on the DC current to impose the high frequency on the drive
current of the laser. Thus, the interference of outgoing light and reflected light is prevented.

Monitor Diode

Basic Structure of Laser Diode

Laser Diode

8-4-6. HF Signal (VA, VB, VC, VD)
Signals recorded in the disk

LD

PD

When the quantity of laser light increases, the current shown in
figure increases and the PD terminal voltage rises.
IC303 is used to control. The LD terminal voltage lowers, and
the quantity of light reduces. (IC303 is actuated by voltage
input.)

Memory Test Mode

Program version indicaiton.

Video Test Mode

Ordinary test pattern indication, and copy guard signal added test

pattern indication are given.

Mecha Test Mode

Servo system initialization, tray opening and closing, laser, servo,

continuous playback, jump test are performed.

Servo adjustment

Servo version indication, VC/FE/TE/RF AVRG, TRVSC, RF

value read mode

LEVEL, FO BIAS, FO GAIN, TR GAIN indication are given.

Test Mode Operation

SystemOpe( )

DVDOpe( )

Systest( )

DVD Disc detection

CD Disc

detection

No Disc and

Test 0 (F0h) key

Eject or

error

Eject or

error

Power

Off

Power

Off

Memory Test

Model number

Program version

Region code

microcode version

 

Dynamic

Test

Tray Open/Close

Sled Move

DVD Servo

CD Servo

Video Test

Initial Screen

Test Pattern

'1' Key

'2' Key

'3' Key

FlashOpe( )

Reset

Start

Flash rewriting key

Static Test

Test0

(F0h)

key

Branching with

ten keys

Test0

Key

Test0

Key

Test0

(F0h)

key

OSD 

Adjustment

value display

OSD 

Adjustment

value display

Initial resetting

CDOpe( )

Note: For test mode input,

"F0h" = PLAY + Stop

The keys of main body are doubly pressed.

Systest( )

(0xF100)

 

Dinamic

Test

Video

Test

'1' Key

'2' Key

'3' Key

Transition of test mode status 

(1)

Memory Test

Last Update display

ErrDisplay0  ErrDisplay1

10000000     ********

   (last update)

   (last update)

Play Key

System( )

Test0 Key

SystemMode

=

0xF100-0xF1FF

Memory Test

Model number

Program version

Region code

microcode version

Model Number display

   (Model Number)

Play Key

Region code display

   (Region code)

Play Key

Microcode version

display

  (Microcode. Ver)

Play Key

Program Version display

 (Program version)

Play Key

Servo version display

  (Servo. Ver)

Play Key

ErrDisplay0  ErrDisplay1

10000001     ********

ErrDisplay0  ErrDisplay1

10000002     ********

ErrDisplay0  ErrDisplay1

10000004     ********

ErrDisplay0  ErrDisplay1

10000005     ********

ErrDisplay0  ErrDisplay1

10000003     ********

SysTest( )

(0xF100)

Memory

Test

 

Dinamic

Test

'1' Key

'2' Key

'3' Key

System( )

Test0 Key

Video

Test

SystemMode

=

0xF201-0xF204

(1)Test pattern display

    20000001   00000000

(2)Copy guard (AGC alone)

    20000002   00000000

Play

key

Play

key

Play

key

Play

key

Test0

Key

(3)Copy guard

    (AGC + Color stripe 1)

    20000003   00000000

(4)Copy guard

    (AGC + Color stripe 2)

    20000003   00000000

Transition of test mode status 

(2)

Video Test

In Video Test mode, the color bar test pattern

is first displayed and output, and the display 

data mode is changed every entry of PLAY key

as shown in the right. Here, it returns to Sys 

Test ( ) if any Test 0 (F0h) key is input in the 

test display.

Transition of test mode status 

(3)

Dinamic Test

Systest( )

(0xF100)

Memory

Test

Dynamic

Test

'1' Key

'2' Key

'3' Key

System( )

Test0 Key

Video

Test

SystemMode

=

0xFC00-0xFDFF

 Servo Initialize

ErrDisplay0  ErrDisplay1

30000000     00000000

ErrDisplay0   ErrDisplay1

3000E000       EEEEEEEE

(Servo Initial Err)

Tray Eject

ErrDisplay0  ErrDisplay1

30000001     00000000

ErrDisplay0   ErrDisplay1

3000E001       EEEEEEEE

(Tray Eject Err)

Open/Close Key 

or hand-push  Wait

Tray Load

ErrDisplay0  ErrDisplay1

30000002     00000000

ErrDisplay0   ErrDisplay1

3000E002       EEEEEEEE

(Tray Load Err)

Test0 Key

 Wait

SRV Play Test (  )

Continuous replay jump

 test mode

'1' or '2'or'3'

Key Wait

SRV Step Test (  )

Step execution mode

Laser Test (  )

Laser Test 

mode

'1'

'2'

'3'

'1'

 Key Wait

Refer to the step

test mode.

Refer to the jump

test mode.

ErrDisplay0  ErrDisplay1

DD000100     00000000

ErrDisplay0  ErrDisplay1

DD000200     00000000

ErrDisplay0  ErrDisplay1

DD000300     00000000

Every input of "1" key, LDON &

the sled moves outward, and the 

spindle motor moves also insignificantly.

Note: Tray Err is not 

retried in the mode.

SRV Step Test( )

SRV Step Test( )

Step Test Mode

ex. DVD mode

ErrDisplay0    ErrDisplay1

DD000200     00000000

ErrDisplay0    ErrDisplay1

DD000204      7 000000

ErrDisplay0    ErrDisplay1

DD000205     9  

11

 0000

ErrDisplay0    ErrDisplay1

DD000206   

7  4  5 00(CD)

                    8 5 

0000(DVD)

AdjDisplay( )

(0xFF00)

'PLAY'

'STILL'

'PLAY'

'PLAY'

'STILL'

'STILL'

'PLAY'

DDT step 1 operation

ErrDisplay0    ErrDisplay1

DD000201      2  3  4 00

ErrDisplay0    ErrDisplay1

DD00E201   2  3  4 EE

'PLAY' or 'STILL'

'STILL'

ErrDisplay0    ErrDisplay1

DD000202     6 000000

'PLAY'

'STILL'

ErrDisplay0    ErrDisplay1

DD000203      4  6  

11

 00

'PLAY'

'STILL'

DDT step 1 operation

   Executed till focus of DDT is turned on.

The numerals shown on Err Display 1 

indicate the following adjustment values.

DDT step 2 operation

   Track balance adjustment and track 

   thread on are executed.

DDT step 3 operation

   After RF gain is adjusted for a certain 

   time, the just focus is adjusted.

   After end, RF gain adjustment is started

   again.

DDT step 4 operation

   Focus gain is adjusted.

DDT step 5 operation

   Track gain is adjusted.

DDT step 6 operation

   On the 2-layer disc, the just focus 

   adjustment and focus gain adjustment

   of layer 1 are done.

   On CD, interrupt of SUB-Q is allowed, 

   TOC is read/set, and mute is turned off.

(for error)

(for error)

(for error)

(for error)

(for error)

(for error)

ErrDisplay0    ErrDisplay1

DD00E202     6 0000EE

ErrDisplay0    ErrDisplay1

DD00E203     4  6  

11

 EE

ErrDisplay0    ErrDisplay1

DD00E204    7 0000EE

ErrDisplay0    ErrDisplay1

DD00E205     9  

11

 00EE

ErrDisplay0    ErrDisplay1

DD00E206  

7  4  5 

EE(CD)

                     8 5 

00EE(DVD)

DDT step 2 operation

DDT step 3 operation

DDT step 4 operation

DDT step 5 operation

DDT step 6 operation

'PLAY' or 'STILL'

'PLAY' or 'STILL'

'PLAY' or 'STILL'

'PLAY' or 'STILL'

'PLAY' or 'STILL'

Servo adjustment value

Reading-out mode

SRVPlayTest( )

Continuous replay & jump mode

ErrDisplay0    ErrDisplay1

DD000300      ********

SRV Play Test( )

In the continuous replay mode, the current sector 

address is displayed on ErrDisplay 1.

Key Wait

TR Jump command publication

In SRV Play Test (  ), key is input and number of TR jumps is specified as follows.

[Next replay]

 = Layer Jump

* Here, key allocation may be changed.

* Layer jump operation is not guaranteed except during 2-layer DVD test.

Key    Name

[1]

[4]

[7]

[Clear]

[2]

[5]

[8]

[Skip(-)]

(Code)

01h

04h

07h

1Fh

02h

05h

08h

2Dh

Jump   

Number of TRs

-1

-102

-510

-511

-765

-766

-7000

-15000

Key    Name

[3]

[6]

[9]

[Memory]

[Repeat]

[A-B]

[Program]

[Skip(+)]

(Code)

02h

06h

09h

1Ch

35h

36h

1Eh

2Eh

Jump   

Number of TRs

+1

+102

+510

+511

+765

+766

+7000

+15000

2

...........

 Focus Offset

3

...........

 Track Offset

4

...........

 0-Layer Focus Balance

5

...........

 1-Layer Focus Balance

..............

 In case of CD, focus balance after correction.

6

...........

 Track Balance

7

...........

 0-Layer Focus Gain

8

...........

 1-Layer Focus Gain

9

...........

 Track Gain

11

...........

 RF Gain