LG FFH-818 Schematic

4

SERVICING PRECAUTIONS

NOTES REGARDING HANDLING OF THE PICK-UP

1. Notes for transport and storage

1) The pick-up should always be left in its conductive bag until immediately prior to use.

2) The pick-up should never be subjected to external pressure or impact.

2. Repair notes

1) The pick-up incorporates a strong magnet, and so should never be brought close to magnetic materials.

2) The pick-up should always be handled correctly and carefully, taking care to avoid external pressure and impact. If it is subjected to strong pressure or impact, the result may be an operational malfunction and/or damage to the printed-circuit board.

3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reason the adjustment point and installation screws should absolutely never be touched.

4) Laser beams may damage the eyes! Absolutely never permit laser beams to enter the eyes! Also NEVER switch ON the power to the laser output part (lens, etc.) of the pick-up if it is damaged.

5) Cleaning the lens surface If there is dust on the lens surface, the dust should be cleaned away by using an air bush (such as used for camera lens). The lens is held by a delicate spring. When cleaning the lens surface, therefore, a cotton swab should be used, taking care not to distort this.

6) Never attempt to disassemble the pick-up. Spring by excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab. (Do not use any other liquid cleaners, because they will damage the lens.) Take care not to use too much of this alcohol on the swab, and do not allow the alcohol to get inside the pick-up.

Storage in conductive bag

Drop impact

NEVER look directly at the laser beam, and don

¡˙t let

contact fingers or other exposed skin.

Magnet

How to hold the pick-up

Pressure

Cotton swab

Conductive Sheet

5

NOTES REGARDING COMPACT DISC PLAYER REPAIRS

1. Preparations

1) Compact disc players incorporate a great many ICs as well as the pick-up (laser diode). These components are sensitive to, and easily affected by, static electricity. If such static electricity is high voltage, components can be damaged, and for that reason components should be handled with care.

2) The pick-up is composed of many optical components and other high-precision components. Care must be taken, therefore, to avoid repair or storage where the temperature of humidity is high, where strong magnetism is present, or where there is excessive dust.

2. Notes for repair

1) Before replacing a component part, first disconnect the power supply lead wire from the unit

2) All equipment, measuring instruments and tools must be grounded.

3) The workbench should be covered with a conductive sheet and grounded. When removing the laser pick-up from its conductive bag, do not place the pick-up on the bag. (This is because there is the possibility of damage by static electricity.)

4) To prevent AC leakage, the metal part of the soldering iron should be grounded.

5) Workers should be grounded by an armband (1MΩ)

6) Care should be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent static electricity changes in the clothing to escape from the armband.

7) The laser beam from the pick-up should NEVER be directly facing the eyes or bare skin.

Armband

Conductive Sheet

Resistor (1 Mohm)

6

ESD PRECAUTIONS

Electrostatically Sensitive Devices (ESD)

Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD devices are integrated circuits and some field-effect transistors and semiconductor chip components. The following techniques should be used to help reduce the incidence of component damage caused by static electricity.

1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging wrist strap device, which should be removed for potential shock reasons prior to applying power to the unit under test.

2. After removing an electrical assembly equipped with ESD devices, place the assembly on a conductive

surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.

3. Use only a grounded-tip soldering iron to solder or unsolder ESD devices.

4. Use only an anti-static solder removal device. Some solder removal devices not classified as "anti-static" can

generate electrical charges sufficient to damage ESD devices.

5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ESD

devices.

6. Do not remove a replacement ESD device from its protective package until immediately before you are

ready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together by conductive foam, aluminum foil or comparable conductive materials).

7. Immediately before removing the protective material from the leads of a replacement ESD device, touch the

protective material to the chassis or circuit assembly into which the device will by installed.

CAUTION : BE SURE NO POWER IS APPLIED TO THE CHASSIS OR CIRCUIT, AND OBSERVE ALL OTHER

SAFETY PRECAUTIONS.

8. Minimize bodily motions when handing unpackaged replacement ESD devices. (Otherwise harmless motion

such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity sufficient to damage an ESD device).

- 30 -

Pre Out

Ch2

3.3µF

1000µF

47µF

0.018µF

1000µF

3.3µF

47µF

1.2µF

100 µF

R . R

Vcc

1000 µF

47µF

0.018µF

10kΩ

150kΩ

1MΩ

2.2kΩ

Rec IN Ch2

Rec

IN

Rec IN Ch1

ALC

Rec Out Ch2

180kΩ

Gv

Gvo

180kΩ

1kΩ

100kΩ

100Ω

10kΩ

10Ω

300kΩ

9.1kΩ

100Ω

Pre IN Ch2/B

(Play Rec)

Pre IN Ch2/A

(Play only)

Pre IN Ch1/B

(Play Rec)

Pre Out

Ch1

Pre IN Ch1/A

Ch1/B

NF

Ch2/A

Ch1/A

Ch1/B

Gvo

Gv

Gvo

Gv

Vcc

M

N

NF

Ch1

Ch2

Gvc

GV

Ch2

ALC

GND

Rec

15

14

13

12

11

23

24

1

2

161718192122

IN

Vref1

Vref

Vref2

A/B

Metal Out

Pre Out

REC Out

Rec Out Ch1

Mix Out

GND1 M/N

6.8kΩ

A

B

1000pF

6.8kΩ

9.1kΩ

20

10 9876435

M/N

REC SW REC SWGND P/B SW P/B SWCONT GND GNDV

CC

123456789

KA3082

KIA6289N

- 30 -

INTERNAL BLOCK DIAGRAM OF ICs

LA1837

- 31 -

KA8301

KIA7805 P/PI ~ KIA7824P/PI

DRIVER

PRE

LOGIC

2 3 4 5 6 7 8 9 101

GND

Vout1

Vz1VrFin

Rin

Vcc1

Vcc2

Vz2

Vout2

3

1

2

4

R

12

R

1

C

21

R

12

Q

1

Q

7

Q

13

Q

10

Q

6

Q

5

Q

4

Q

3

Q

11

Q

15

Q

14

Q

9

Q

8

Q

16

Q

17

Q

INPUT

OUTPUT

GND

2

Q

1

Z

18

R

8

R

9

R

13

R

11

R

17

R

5

R

6

R

1

R

2

R R

16

R

20

R

19

R

14

R

10

R

7

R

- 32 -

LC7273M

TDA7440D

+5V

VREF

CINFLOUTVREF

Vdda

Vssa

MPXIN

TEST

XIN XOUT

Vssd

Vddd

RDCL

RDDA

MODE

RST

RDS-ID READY

CLK(4.332MHz)

SMOOTHING

FILTER

OSC

PLL

(57kHz)

DATA

DECODER

RAM

(128bit)

RDS-ID

DETECT

CLOCK

RECOVERY

(1187.5Hz)

ANTIALIASING

FILTER

REFERENCE

VOLTAGE

57kHz

BPF

(SCF)

TEST

L-IN1

100K

4 8 9 18

27

21 22

20

26

24 25

LOUT

SCL SDA

DIG_GND

ROUT

V

S

AGND

R

B

R

B

14 15

10 11 19 12 13 23

5

G

6

7

3

2

INPUT MULTIPLEXER

+GAIN

MUXOUTR INR TREBLE(R) BIN(R) BOUT(R) CREF D98AU883

0/30dB

2dB STEP

MUXOUTL

VOLUME TREBLE

I CBUS DECODER + LATCHES

BASS

SPKR ATT

LEFT

VOLUME TREBLE BASS

SUPPLY

V

REF

SPKR ATT

RIGHT

INL TREBLE(L) BOUT(L)BIN(L)

1

28

L-IN2

L-IN3

L-IN4

R-IN1

R-IN2

R-IN3

R-IN4

2

- 33 -

STK411-220E

- 34 -

MSGEQ7

Audio

In

Anti-Alias

Filter

Clock

Oscillator

Output

Multiplexor

CKIN

Reset

63Hz

Bandpass

160Hz

Bandpass

400Hz

Bandpass

1kHz

Bandpass

2.5kHz

Bandpass

6.25kHz

Bandpass

16kHz

Bandpass

Peak

Detector

Peak

Detector

Peak

Detector

Peak

Detector

Peak

Detector

Peak

Detector

Peak

Detector

Strobe

DC Out

LC72131, 72131M

B01 B02 B03 B04 I01 I02

XIN

PD

AIN

AOUT

IFIN

XOUT

FMIN

AMIN

CE

DI

CL

D0

VDD

VSS

REFERENCE DIVIDER

PHASE DETECTOR CHARGE PUMP

UNLOCK DETECTOR

UNIVERSAL COUNTER

DATA SHIFT REGISTER

LATCH

12bits PROGRAMMABLE

DIVIDER

SWALLOW COUNTER

1/16. 1/17 4bits

POWER

ON

RESET

CCB

I/F

1

2

- 35 -

KA3010

PIN DESCRIPTION

28 27

26 25 24 23 22

T S D

REGULATOR

MUTE

LEVEL

SHIFT

LEVEL

SHIFT

100K

50K

10K

10K 10K

10K

BUY

LEVEL

SHIFT

LEVEL

SHIFT

1 2 3 4 5 6 7

8 9 10 11 12 13 14

21 20 19 18 17 16 15

Pin No. Symbol I/O Description

1 DO1.1 O DRIVE OUTPUT

2 DO1.2 O DRIVE OUTPUT

3 DI1.1 I DRIVE INPUT

4 DI1.2 I DRIVE INPUT

5 REG REGULATOR

6 REO O REGULATOR OUTPUT

7 MUTE MUTE

8 GND1 GROUND

9 DI2.1 I DRIVE INPUT

10 DI2.2 I DRIVE INPUT

11 DO2.1 O DRIVE OUTPUT

12 DO2.2 O DRIVE OUTPUT

13 GND2 GROUND

14 OPOUT O OPAMP OUTPUT

15 OPIN (-) I OPAMP OUTPUT (-)

16 OPIN (+) I OPAMP INPUT (+)

17 DO3.1 O DRIVE OUTPUT

18 DO3.2 O DRIVE OUTPUT

19 DI3.1 I DRIVE INPUT

20 DI3.2 I DRIVE INPUT

21 VCC1 SUPPLY VOLTAGE

22 VCC2 SUPPLY VOLTAGE

23 VREF 2.5V BIAS VOLTAGE

24 DI4.1 I DRIVE INPUT

25 DI4.2 I DRIVE INPUT

26 DO4.1 O DRIVE OUTPUT

27 DO4.2 O DRIVE OUTPUT

28 GND3 GROUND

- 36 -

KB9223

MICOM TO SERVO CONTROL

AUTO SEQUENCER

FOK DETECTION CIRCUIT

MIRROR DETECTION CIRCUIT

Spindle Servo LPF (Double Speed)

Sled Servo Amplifier & Sled Kick GEN.

Tracking Phase Compensation Block & Jump Pulse GEN.

Focus Phase Compensation & Offset cancel circuit

Micom Data

Interface Logic

RF Amp

73

74

65

66

63

67

68

79

69

70

71

78

76

75

32

33

77

2

4

RF-

RFO

PD1

PD2

F

E

EI

PD

LD

VR

ARF

IRF

ASY

EFM

RFI

DCB

DCC1

GC1O

MLT

TZC

FE2

FLB

FGD

FS3

TE1

FE1

GC1I

CH1O

CH1I

MUTEI

RRC

CH2O

CH2I

GC2I

GC2O

5

15 16 13 14 19 17 12 11 9 10

40

1

39

6

25

24

23

45

46

42

44

43

61

62

55

53

50

49

57

48

47

60

FOK

MCP

MIRROR

FSET

SMEF

SMON

FS1 to FS4

TM1 to TM6

BAL1 to BAL5

PS1 to PS4

GA1 to GA5

SMPD

SPDL-

SPDLO

SL+

SL-

SLO

TGU

TG2

LPFT

TE2

TEO

TE-

TDFCT

FEO

FE-

FDFCT

327282658525135363738312930225459

APC Amp

Center Voltage Amp.

Focus Error Amp FE-BIAS Adjustment

Tracking Error Amp E/F Balance & Gain Control

RF Level AGC & Equalizer

EFM Comparator

Defect Detection CircuitT

ADJUSTMENT-FREE CONTROL

Built-in Post Filter Amp(L&R)

LDON

PIN DESCRIPTION

Pin No. System Description

1 MCP Capacitor connection pin for mirror hold 2 DCB Capacitor connection pin for defect Bottom hold 3 FRSH. Capacitor connection pin for time constant to generate focus search waveform 4 DCC2 The input pin through capacitor of defect bottom hold output 5 DCC1 The output pin of defect bottom hold 6 FSET The peak frequency setting pin for focus, tracking servo and cut off frequency of CLV LPF 7 VDDA Analog VCC for servo part 8 VCCP VCC for post filter

9 GC2I Amplifier negative input pin for gain and low pass filtering of DAC output CH2 10 GC2O Amplifier output pin for gain and low pass filtering of DAC output CH2 11 CH2I The input pin for post filter channel2 12 CH2O The output pin for post filter channel2 13 CH1O The output pin for post filter channl1 14 CH1I The input pin for post filter channel1 15 GC1O Amplifier output pin for gain and low pass filtering of DAC output CH1