LG LAC-6700-R Service manual

CAR CD/MP3/WMA RECEIVER

SERVICE MANUAL

MODEL :

LAC6700R

CAUTION

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

MODEL : LAC6700R

SERVICE MANUAL

P/NO : AFN35097871

OCTOBER, 2007

Website http://biz.lgservice.com

Internal Use Only

1-1

CONTENTS

SECTION 1 SUMMARY

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

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

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

SECTION 2 ELECTRICAL

ELECTRICAL TROUBLESHOOTING GUIDE & WAVEFORMS .............................................................................2-1

1. MAIN, FRONT & TUNER PART................................................................................................................................2-1

2. CD PART TROUBLESHOOTING .............................................................................................................................2-4

3. USB PART TROUBLESHOOTING...........................................................................................................................2-7

• WAVEFORMS..............................................................................................................................................................2-9

INTERNAL BLOCK DIAGRAM OF ICs......................................................................................................................2-12

1. IC518, IC701 & IC702 (S4580) ...............................................................................................................................2-12

2. IC301 (HA13173AH) ................................................................................................................................................2-12

3. IC302 (BA00CCOWFP) ...........................................................................................................................................2-14

4. IC401 (µPD78F1164) ...............................................................................................................................................2-14

5. IC601 (TDA7419) .....................................................................................................................................................2-17

6. IC602 (NJM2706-DMP24) .......................................................................................................................................2-19

7. IC801 (TB2904HQ) ..................................................................................................................................................2-20

8. IC901 (LD3811) ........................................................................................................................................................2-21

BLOCK DIAGRAM .........................................................................................................................................................2-23

CIRCUIT DIAGRAMS.....................................................................................................................................................2-25

1. MAIN CIRCUIT DIAGRAM ......................................................................................................................................2-25

2. CDP 1 CIRCUIT DIAGRAM ....................................................................................................................................2-27

3. CDP 2 CIRCUIT DIAGRAM ....................................................................................................................................2-29

4. FRONT CIRCUIT DIAGRAM ..................................................................................................................................2-31

5. USB CIRCUIT DIAGRAM........................................................................................................................................2-33

6. LCD LIGHTING CIRCUIT DIAGRAM.....................................................................................................................2-34

PRINTED CIRCUIT DIAGRAMS..................................................................................................................................2-35

1. MAIN P.C.BOARD ....................................................................................................................................................2-35

2. CDP P.C.BOARD .....................................................................................................................................................2-39

3. FRONT P.C.BOARD ................................................................................................................................................2-40

4. USB P.C.BOARD......................................................................................................................................................2-41

5. LCD LIGHTING P.C.BOARD...................................................................................................................................2-41

SECTION 3 EXPLODED VIEWS

1. CABINET AND MAIN FRAME SECTION ................................................................................................................3-1

2. MECHANISM(PICK-UP) SECTION..........................................................................................................................3-3

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

LGE Internal Use Only

1-2

1. 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.

2. Do not defeat any plug/socket B+ voltage interlocks with which instruments covered by this service manual might be equipped.

3. Do not apply power to this instrument and or any of its electrical assemblies unless all solid-state device heat sinks are correctly installed.

4. 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.

SERVICING PRECAUTIONS

SECTION 1 SUMMARY

LGE Internal Use Only

Only for training and service purposes

1-3

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 know 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 ARROWHEAD 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 INTENED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE.

LGE Internal Use Only

1-4

SPECIFICATIONS

• GENERAL

Output Power 50W x 4CH (Max.)

Power Source DC 12V

Speaker impedance 4Ω

Ground System Negative

Dimensions (W x H x D) 180 x 51 x 171mm (Without Control Panel)

Net Weight 2.0kg

• CD SECTION

Frequency Response 20Hz ~ 20kHz

S/N Ratio 85dB

Distortion 0.05%

Channel Separation (1kHz) 60dB

• RADIO SECTION

Frequency Range 65 ~ 74, 87.5 ~ 107.9 or 87.5 ~ 108MHz

S/N Ratio 53dB

Distortion 0.7%

Usable Sensitivity 12dBµV

AM (MW)

Frequency Range 520 ~ 1720 or 522 ~ 1620kHz

S/N Ratio 45dB

Distortion 1.0%

Usable Sensitivity 28dBµV

• USB SECTION

Version USB 1.1

LGE Internal Use Only

Only for training and service purposes

2-1

SECTION 2 ELECTRICAL

1. MAIN, FRONT & TUNER PART

No Symptom Check Point Location No.

SYSTEM CONTROL

1 No Power Checked the Fuse. CN801

Checked the Back up Vdd, Gnd. CN801(16, 15) Checked the Micom Back Up Vdd. IC301(14),D307, IC401(30,47,50,99,100) Checked the Micom Ground. IC401(20,51,97,98) Checked the Reset. IC402. IC401(90) Checked the X-tal. X401, X402 Checked the ACC in. Q301,Q302, IC401(38), CN801(14) Checked the detachable switch. SW401, IC401(73) Checked the flipdown Detector. CN901(19), IC401(74) Checked the Key line. IC401(52,53)

2 Not available Remocon Checked the Remocon Sens Vdd. CN901(14),Q316,Q317,D307

Checked the Remocon Sens line. RM901, IC401(5)

3 Not available to Volume control Checked the Encoder Volume. SW901, IC401(40,41) 4 Not available to Key Control Checked Tact switch. SW902 ~ SW918

Checked Key line. IC410(52,53)

5 No sound Checked the E-VR Vdd. IC301(10),IC601(24)

Checked the E-VR Ground. IC601(15) Checked the E-VR control. IC601(22,23), IC401(1,2) Checked the E-VR Signal in/out. IC601(5,6,7,8,9,10,11,13)

IC601(17,18,19,20)

Checked the E-VR Mute Control IC601(21), IC401(6)

* Power IC Checked the Power IC Vdd. IC801(6, 20)

: Refer to next page Checked the Power IC Ground. IC801(1, 2, 8, 13, 18, 24)

Checked the Power IC Control. IC801(4, 22), IC401(3,10) Checked the Power IC Signal in/out. IC801(11,12, 14, 15)

IC801(3,5,7,9,17,19,21,23) Checked the Power IC Mute. IC801(22) Checked the Power IC Standby. IC801(4) Checked the Power IC Ripple. IC801(10) Checked the Main Connector. CN801(1,2, 3, 4, 8, 9, 12, 13)

6 No Line out signal Checked the E-VR Vdd. IC301(10),IC601(24)

Checked the E-VR Ground. IC601(15) Checked the E-VR control. IC601(22,23), IC401(1,2) Checked the E-VR Signal in/out. IC601(5,6,7,8,9,10,11,13)

IC601(17,18,19,20) Checked the OPAMP Vdd. IC701(8),IC702(8) Checked the OPAMP Ground. IC701(4),IC702(4) Checked the OPAMP Signal in/out IC701(3,5,7,1)

IC702(3,5,7,1) Checked the Line out Mute circuit Q705,IC401(48) Check the Line out Jack CN703

8 Heard Pop Noise Checked the Mute Control. IC601(21), IC801(4, 22), IC401(3,6,10)

Checked the AF Mute. TU101(19), IC401(4)

9 Not avaliable to Telephone Mute Checked the telephone Mute Control. CN801(5), Q305,Q306, IC401(62)

Checked the Mute Control. IC601(21), IC801(4, 22), IC401(3,6,10)

10 Not avaliable to ANT(Motor Type) Control Checked the ANT Control. IC301(12,13),IC401(87) 11 Not avaliable to Remote Checked the Remote control. CN801(6), IC402(1,2,4),Q308,Q309

(External AMP) IC401(63,64)

12 No output Beep sound. Checked the Beep Control. IC401(80), BU301

ELECTRICAL TROUBLESHOOTING GUIDE & WAVEFORMS

LGE Internal Use Only

2-2

CAUTION - Tip for repair

Before exchange power amp IC(TB2904) for no audio problem, you have to check

below list.

1. Check VCC (pin 20, 6) & GND

2. Check input pin 11, 12, 14, 15

3. Check Standby, pin 4

: Follow the below list.

4. Check Mute function, pin 22

: Follow the below list.

5. Check Ripple pin 10.

: Normally it is high (about 10V)

6. Re-soldering all the pin of IC.

: Prevent crack of solder line.

* Keep changed IC, We request that you send it to HQ.

Stand-by Power Sound Voltage

ON OFF OFF 0 to 1.5

OFF ON ON 3.5 to 6V

Mute Sound Voltage

ON OFF 0 to 1.5

OFF ON 3.5 to 6V

Picture 1) Power IC desc.

PRE-GND

1 20 6

TAB V

IN1

IN2

C-GND

IN3

IN4

STBYRIP

10 25 22

CC1VCC2

OFF-SET

DET

OUT1

()

PW-GND1

OUT1 ( )

OUT2 ( )

PW-GND2

OUT2 ( )

OUT3 ( )

PW-GND3

OUT3 ( )

OUT4 ( )

PW-GND4

OUT4 ( )

MUTE

5 V

PLAY

MUTE

: PRE-GND

: PW-GND

LGE Internal Use Only

Only for training and service purposes

2-3

No Symptom Check Point Location No.

DISPLAY & LIGHTING

1 No Display or Checked the LCD DRV Vdd. Q322,Q316,Q317

Some Display is broken IC901(69,70,71,72,73)

Checked the LCD DRV Ground. IC901(74) Checked the LCD DRV OSC. IC901(75,76) Checked the LCD DRV control. IC401(75,79,85,86),

IC901(77,78,79,80)

Checked the LCD DRV to LCD Pattern.

IC901(1 ~ 68)

2 No LCD Lighting or Checked the LCD Lighting VDD. Q319,Q320,Q322,IC301(4,9)

Color is different IC401(64)

Checked the LED. LD991, LD992

3 Not avaliable to LCD Lighting Checked the LCD Lighting Control. CN801(11),Q303,Q304,Q321,

control IC401(58)

Checked the LED. LD991,LD992

4 No Key Lighting Checked the LED Lighting Vdd. IC301(4,9),IC401(64)

Checked the LED. LD901 ~ LD921 5 Don't moved Level bar Checked the Level Meter control. IC601(25,26),IC401(9,54) 6 Not avaliable to Dimmer control Chekced the Dimmer control. CN801(11),Q303,Q304,IC301(4,9)

No Symptom Check Point Location No.

TUNER FUNCTION

1 Not available to Tuner Checked the Tuner Vdd. TU101(4,16),IC301(10),IC401(39)

Q350,Q351 Checked the Tuner Ground. TU101(3, 5,10,17) Checked the PLL data. TU101(11,12,13,14,15)

IC401(67,68,44,45,46) Checked the RF signal in. TU101(1, 2) Checked the S-Meter control. TU101(7) Checked the SD & ST IND. TU101(6)

2 Tuner no sound Checked the Tuner Signal out. TU101(8,9), IC601(5,6)

Checked the AF mute. TU101(19), IC401(4)

3 Not available to RDS Checked the RDS data. TU101(20,21), IC401(65,83)

LGE Internal Use Only

2-4

Something wrong with the CD player?

No loading?

YES

CN510(13, 6)

YES

Checked the CD Vdd?

IC506(26, 32, 47, 78, 18)

YES

Checked the CD DSP ground?

IC504(7, 8, 20)

YES

Checked the motor DRV

VDD?

IC506(72)

YES

Checked the CD DSP reset?

X503

YES

Checked the CD DSP X-tal?

PN504(3)

YES

Fig 3, 4

Fig 1, 2

Checked the disc in

load switch?

CN510(12, 17)

IC513(12, 14, 15)

YES

Checked the loading

motor control?

PN504(1)

YES

Checked the 8/12cm

sens switch?

2. CD PART TROUBLESHOOTING

A B C

LGE Internal Use Only

Only for training and service purposes

2-5

No reading & "FILE CHECK"

DISPLAY?

YES

PN504(4)

YES

Fig 1, 2

Fig 3, 4

Fig 10~12

Fig 5

Fig 9

Fig 7

Fig 13

Fig 6

Checked the limit switch?

CN510(16)

YES

Checked the motor DRV

mute control?

D5, D6

YES

Checked the motor

LD control?

IC506(67, 68, 69, 70, 71)

YES

Checked the CD DSP control?

IC506(25)

IC513(17, 18)

YES

Checked the focus control?

IC506(25)

R517

YES

Checked the focus error

level out.(FE mon)?

IC506(54)

YES

Checked the PLL locking.

(FSEQ)?

IC506(41, 16)

YES

Checked the RF signal

out check?

IC506(21)

IC513(8, 5)

YES

Checked the spindle

motor control?

PN504(5, 6)

YES

Checked the TRVP control?

IC506(24)

IC513(19, 20)

YES

Checked the tracking control?

LGE Internal Use Only

2-6

CD no sound?

YES

IC520(1, 2, 3)

YES

Fig 8

Fig 3, 4

Checked the DAC signal in?

No ejected the CD?

YES

CN901(16) [MAIN]

YES

Checked the Eject key?

YES

D6, D5

Checked the loading motor

control?

LGE Internal Use Only

Only for training and service purposes

2-7

Something wrong with the USB?

Only "NO USB" or "USB CHECK" display?

IC512(2), L507, L508, L509, R566

YES

Checked the USB Vdd?

IC511(17, 37, 40, 61, 71)

YES

Checked the USB

interface IC ground?

IC505(24)

YES

Checked the memory

IC ground?

IC511(57), CN510(31)

YES

Checked the USB

interface IC reset?

X505

YES

Checked the USB interface IC X-tal?

IC511(65)

YES

Fig 14

Checked the Flash

memory option port?

IC511(62, 63)

YES

Checked the D+/D- port?

IC511(27)

YES

Checked the USB

indication port?

IC506 (62, 63, 64)

YES

Checked the USB

interface IC control?

3. USB PART TROUBLESHOOTING

YES

LGE Internal Use Only

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