LG LACM-6600, LACM-6600-R Service manual

DETACHABLE FRONT PANEL CAR CD RECEIVER

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS” IN THIS MANUAL.

MODEL : LAC-M6600(R)

SER VICE MANU AL MODEL : LAC-M6600(R)

- 1-1 -

[CONTENTS]

❍ SECTION 1.GENERAL

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

• ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

• SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-4

❍ SECTION 2. ELECTRICAL

• ELECTRICAL TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

• WAVEFORMS OF MAJOR CHECK POINT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

• INTERNAL BLOCK DIAGRAM of ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

• BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

• SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

• PRINTED CIRCUIT DIARGAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

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

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

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SECTION 1. SUMMARY

❏ SERVICING PRECAUTIONS

❶ Always disconnect the power source before:

1) Removing or reinstalling any component, circuit board, module or any other instrument assembly.

2) Disconnecting or reconnecting any instrument electrical plug or other electrical connection.

3) Connecting a test substitute in parallel with an electrolytic capacitor in the instrument.

CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in

an explosion hazard.

❷ Do not defeat any plug/socket B+ voltage interlocks with which instruments covered by

this service manual might be equipped.

❹ Do not apply power to this instrument and or any of its electrical assemblies unless all

solid-state device heat sinks are correctly installed.

❸ Always connect a test instrument’s ground lead to the instrument chassis ground before

connecting the test instrument positive lead. Always remove the test instrument ground lead last.

1) The service precautions are indicated or printed on the cabinet, chassis or components. When servicing, follow the printed or indicated service precautions and service materials.

2) The Components used in the unit have a specified conflammability and dielectric strength. When replacing any components, use components which have the same ratings. Components marked in the circuit diagram are important for safety or for the characteristics of the unit. Always replace with the exact components.

3) An insulation tube or tape is sometimes used and some components are raised above the printed writing board for safety. The internal wiring is sometimes clamped to prevent contact with heating components. Install them as they were.

4) After servicing always check that the removed screws, components and wiring have been installed correctly and that the portion around the service part has not been damaged. Further check the insulation between the blades of attachment plug and accessible conductive parts.

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❏ 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).

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.

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❏ SPECIFICATIONS

1. GENERAL

Power requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DC12V~15V

Ground system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Negative

Dimensions(W x H x D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 x 58 x 166mm

Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Net: 1.3kg

2. RADIO SECTION

FM AM(MW)

Frequency range 65.0~74.0MHz(Optional), 522~1,620kHz

87.5~108MHz (Optional:530~1,710kHz/ 520~1,620kHz) Intermediate frequency 10.8MHz 450kHz Usable sensitivity 10dBµV 28dBµV Signal to noise ratio 55dB 45dB

3. COMPACT DISC SECTION

Frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Hz~20kHz

Channel separation (Line out) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90dB (1kHz)

Signal to noise ratio (Line out) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110dB

4. AUDIO SECTION

Maximum output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50W x 4

Speaker impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Ω x 4 or 8Ω x 4

NOTE: The design and specifications are subject to change without notice in the sourse of product

improvement.

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SECTION 2. ELECTRICAL

❏ ELECTRICAL TROUBLESHOOTING GUIDE

1. No Power.

Any Key power on.

YES

Is power turnd on?

DISC loading?

Does initial reading occur?

Can disc be played?

Is audio output supplied?

Check audio circuitry.

IC501,IC509, CN503

Check tracking servo circuitry.

Q541, IC501, IC503

Check DISC.

Check focusing circuitry.

Q541, IC501

Check laser circuitry.

Q541, IC501

Check loading supply circuitry.

Q901, Q902, Q903, Q904, PN503,

IC507, IC506, IC508

Check power supply circuitry.

Q930, Q924, Q919,

Q920, Q921, IC902, pin1

- 2-2 -

2. LCD light abnornal.

YES

NO NO

Any Key power on.

(without DISC)

Do display LCD then light?

Check voltage in the power

supply circuitry.

Power supply circuitry defective.

Q924, Q930, Q926, Q928,

Q925, IC902

• Reset circuit defective. IC601 Surrounding circuit defective.

• IC906 pin74 defective.

X101, X102, C101,

C102, C103, C104

CN601, PN601, PN103 front

PCB pattern defective.

IC906, Pin75, 76, 78

front PCB pattern defective.

IC601, Surrounding circuit

PCB pattern defective.

Display LCD connector

defective.

Is IC601 Com1~Com10

output waveform normal?

Is u-com IC906 Pin75, 76, 78

output waveform normal?

Is u-com IC901 reset circuit

normal? Pin74

Is u-com IC906 keyin Pin63, 64

5volt input?

Is u-com IC906 X1, X2 terminal

Pin11, 12, 14, 15 input?

OSC : 19.2MHz

OSC : 32.768kHz

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3. Initial reading is not carried out.

YES

YES (with disc)

NO NO

Slide motor moves

(With disc)

Spindle motor turns

WAVEFORM #1

Does RF waveform

appear? IC501 Pin49

WAVEFORM #2

Check the Voltage change of

CN503 Pin12 (6.4~6.8V)

Check the Voltage IC501

Pin23 (1.4V~1.8V)

Check the Data transmission

from CN503 (16, 17, 18) to CD

DSP WAVEFORM

Check the Data transmission

from CN503 Pin21 to MICOM

WAVEFORM

Check the TRVP

Voltage

IC501 Pin25

Check the change of

SL +, SL – Voltage

IC503 Pin13,14

Does FA+ waveform appear at

IC501 Pin23?

WAVEFORM #3

Laser light check A ?

focus coil drive wareform.

TRACKING ERROR wareform

Defective contact CN501

Defective PICK-UP

Defective IC503

Defective IC501

Defective

connector CN503

Defective IC503

Defective connector

CN503 Defective

MICOM

Defective IC501

Defective

connector CN503

Does TE waveform appear at

IC501 Pin24?

WAVEFORM #4

Is rotation normal?

Is there no dropout of RF signal?

Defective IC501

Defective PICK-UP

- 2-4 -

When laser does not light.

Is “2.4V~3.4V” applied to

pin42 of IC501?

( ➀ 3.4V ➁ 2.4V)

Did pickup return to

innermost circular?

Does it stop at inner pick

circular after shift?

Is defect output from LMT

SW applied to Pin7 of

PN503?

Is data transferred from

MICOM IC ?

Does voltage appear at

IC503 Pin 13, 14?

Defective MICOM or CN503.

Defective IC501.

Defective slide motor and/or

connector. (CN502)

Defective LMT SW and/or

connector. (CN502,CN503)

Defective MICOM.

Defective IC501

Is power supplied to laser Q541?

(Q541 collector: about 1.8V)

YES

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