LG LPC-LM440A Service manual

MP3/CD LOGIC DECK
CASSETTE RECORDER

SERVICE MANUAL

MODEL: LPC-LM440A

SERVICE MANUAL MODEL: LPC-LM440A

- 1-1 -

[CONTENTS]

❍ SECTION 1.GENERAL

• SERVICING PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

• ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

• SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5

• IDENTIFICATIONS OFCONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

❍ SECTION 2.ELECTRICAL SECTION

• ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

• TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

• INTERAL BLOCK DIAGRAM OF ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

• IC/TR VOLTAGE & PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

• BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

• SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29

• WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-41

• PRINTED CIRCUIT BOARD DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-43

❍ SECTION 3. EXPLODED VIEWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

❍ SECTION 4. REPLACEMENT PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

- 1-2 -

SECTION 1. GENERAL

❏ 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

Conductive Sheet

Cotton swab

Pressure

Pressure

- 1-3 -

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 (1M Ω)

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.

Resistor
(1 Mohm)

Conductive
Sheet

Resistor
(1 Mohm)

Armband

- 1-4 -

❏ 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 sur-

face 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).

CAUTION. GRAPHIC SYMBOLS

THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS
INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED “DAN­GEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF
ELECTRIC SHOCK.

THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE
SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE
LITERATURE.

- 1-5 -

❏ SPECIFICATIONS

[General]

[CD]

[

TAPE

]

Power supply Refer to the back panel of the unit.

Power consumption 40W

Mass

External dimensions (W x H x D) 456 x 178 x 338 mm

Output Power 5W X 2 , 10W

Speakers

3.2Ω

X 3

Battery Operation DC 12V, 8 “D”(R20) batteries (not supplied)

Frequency response 100 - 18000 Hz

Signal-to-noise ratio 65 dB

T.H.D %

Tuning Range 87.5 -108 MHz, 65 -74 MHz or 87.5 -108 MHz

Intermediate Frequency 10.7 MHz

Antenna Telescopic antenna

Tuning Range 522 - 1620 kHz or 520 - 1720kHz

Intermediate Frequency 450 kHz

Antenna Ferrite bar antenna

Recording System 4 Tracks 2 channel stereo

Frequency Response 125 - 8000Hz

Signal to Noise Ratio 40/45dB (REC/PLAY)

Designs and specifications are subject to change without notice.

MODEL

SECTION

[Tuner]

AM

FM

(MW)

LPC-LM440A

5.1kg

0.5

- 1-6 -

❏ IDENTIFICATIONS OF CONTROLS

Front Front

- 1-7 -

Rear Panel

Remote Control

Bottom Panel

- 1-8 -

- 2-1 -

SECTION 2. ELECTRICAL

❏ ADJUSTMENTS

1.TAPE DECK ADJUSTMENT

DECK MODE TEST TAPE TEST POINT ADJUSTMENT ADJUST FOR

PLAY BACK MTT-114 L/R Output L/R Maximum

2.RECORD BIAS ADJUSTMENT

DECK MODE TEST TAPE TEST POINT ADJUSTMENT ADJUST FOR

AUTO-RVS 75KHz±5KHz

AUTO-STOP 65KHz±5KHz

3.TAPE SPEED ADJUSTMENT

DECK MODE TEST TAPE TEST POINT ADJUSTMENT ADJUST FOR

PLAYBACK MTT-111 L/R Output 3kHz±50Hz

Azimuth adjusting screw

SR490

REC MODE MTT-5511

C465 OR C415(DECK

CIRCUIT B- POINT)

L405

- 2-2 -

❏ TROUBLESHOOTING GUIDE

• CD PART

TURN ON CD

OPEN CLOSE CHECK

CONNECTOR CHECK (PN813)

“READING”

DISPLAY CHECK

CONNECTOR CHECK

(PN802,PN806)

CHECK MICOM INTERFACE

CIRCUIT (PN805)

READING OK CHECK

CONNECTOR CHECK (PN801)

CHECK PICKUP MOVEMENT

CHECK AM5810FP (IC802)

CHECK LC78690N (IC801)

CONNECTOR CHECK

(PN806 Pin1 & Pin3)

IF PLAY, AUDIO

OUTPUT CHECK

OK

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

NO

- 2-3 -

OPEN COLOSE NG

“READING ”DISLPAY CHECK (=ONLY “CD ”DISPLAY)

DOOR OPEN/CLOSE

DISLPLAY CHECK

OPEN/CLOSE S/W CHECK

DEFECTIVE CONNECTOR OR

MAIN POWER SUPPLY

DEFECTIVE IC804

DEFECTIVE MICOM OR

DSP &14P FFC CABLE

IC801 PIN=18 CHECK

“2.45V”

PICK-UP UNIT OR Q801

DEFECTIVE

MAIN B`D CHECK

Q102 “C ”➞ 4.6V)

Check Q101 “B ”4.5V

CONNECTOR LOCKING

CHECK (PN813)

AD 5V CHECK(PN805 Pin3)

CONNECTOR LOCKING CHECK

(PN801,PN805,PN802,PN806)

CHECK POWER SUPPLY

(MAIN PN251)

PN251 PIN 5=6.2V ,PIN 7=6.2V

CHECK VOLTAGE CD B`D IC804

Pin3=6.2V,Pin 2&4=3.3V

CHECK INTERFACE

WITH MICOM MAIN CN111 Pin

6,7,8,9 ,10,11,12 ,13

LASER ON

CD B`D PN801 Pin 10=1.96V

NO

NO

NO

NO

NO

NO

NO

YES

YES

YES

YES

YES

YES

- 2-4 -

READING OK CHECK (=“NO DISC ”DISPLAY)

CONNECTOR LOCKING

CHECK(PN801)

CHECK PN802 Pin3,4

(SL+,SL-)

CHECK PN801 Pin13,16

(FA-,FA+)

CHECK PN802 Pin5,6

(SP+,SP-)

CHECK PN801 Pin14,15

(TA+,TA-)

CHECK PN801 Pin10(LD)

DEFECTIVE PICKUP OR

IC802 OR IC801

DEFECTIVE PICKUP OR

IC802 OR IC801

DEFECTIVE PICK-UP OR

IC802 OR IC801

DEFECTIVE PICKUP OR

IC802 OR IC801

DEFECTIVE PICKUP OR

IC801 OR Q801

DOES SLED MOVE?

DOSE LENSE MOVE?

(UP&DOWN)

DOSE LASER LIGHT?

DOES SPINDLE ROTATE?

IS READING OK?

YES

YES

YES

NO

NO

NO

NO

NO

NO

NO

NO

NO

NO

YES

YES

A

B

C

D

E

- 2-5 -

READING OK CHECK #A(=“NO DISC ”DISPLAY)

DOSE SLIN WAVEFORM
APPEAR AT (IC802 Pin5)

DRIVE WAVE

DEFECTIVE IC801

DEFECTIVE IC802

DEFECTIVE PICK-UP

SLED MOTOR

DEFECTIVE PN802

CONNECTOR

DOSE SL+WAVEFORM

APPEAR AT(IC802 Pin13 )

SLED MOTOR WAVE

CHECK PN802

CONNECTOR LINE

YES

NO

NO

NO

NO

NO

A

- 2-6 -

READING OK CHECK #B(=“NO DISC ”DISPLAY)

DOSE FAIN WAVEFORM

APPEAR AT (IC802 Pin22)

DRIVE WAVE

DEFECTIVE IC801

DEFECTIVE IC802

DEFECTIVE PICK-UP

FOCUS ACTUATOR

DEFECTIVE PN801

CONNECTOR

DOSE FA+WAVEFORM

APPEAR AT(IC802 Pin16 )

FOCUS COIL DRIVE WAVE

CHECK PN801

CONNECTOR LINE

YES

NO

NO

NO

NO

NO

B

- 2-7 -

READING OK CHECK #C(=“NO DISC ”DISPLAY)

Q801 EMITTER VOLTAGE

CHECK .3.1V O.K

LASER CONTROL

VOLTAGE CHECK

IC801 Pin 18.2.45

DEFECTIVE IC801

DEFECTIVE IC801

DEFECTIVE Q801

DEFECTIVE PICK-UP

FOCUS ACTUATOR

DEFECTIVE PN801

CONNECTOR

Q801 VOLTAGE CHECK

.1.96V

CHECK PN801

CONNECTOR LINE

YES

YES

NO

NO

NO

NO

NO

NO

C