LG LAC2900N Service Manual Download Page 8

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2-1

SECTION 2 ELECTRICAL

ELECTRICAL TROUBLESHOOTING GUIDE & WAVEFORMS

1. SYSTEM CONTROL ERROR CORRECTION FLOW CHART

No power?

Something wrong with the system control?

YES

F301 Inside of CN302

YES

Checked the Fuse?

CN301(16,15)

YES

Checked the Back up

Vdd and Gnd?

IC301(15,14)

YES

Checked the Regulator

Back up Vdd ?

IC402(30,47,50,99,100)

YES

Checked the Main Micom

Back up Vdd?

IC402(20,51,97,98)

YES

Checked the Main Micom

Back up Gnd?

X401, X402

YES

Checked the Main

Micom X-tal?

IC401, IC402(90)

Checked the Main

Micom Reset?

Q301, R408, IC402(38)

YES

Checked the ACC in?

SW402, IC402(87)

YES

Checked the

detachable switch?

IC402(53,54), CN901(11,13)

YES

Checked the Front

Panel KEY input?

Summary of Contents for LAC2900N

Page 1: ...JUNE 2009 CAR CD MP3 WMA RECEIVER SERVICE MANUAL MODEL LAC2900N CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL Website http biz lgservice com Internal Use Only MODEL LAC2900N SERVICE MANUAL ...

Page 2: ...1 6 AUX ERROR CORRECTION FLOW CHART 2 14 WAVEFORMS 2 15 CIRCUIT VOLTAGE CHART 2 17 INTERNAL BLOCK DIAGRAM OF ICs 2 18 1 IC301 HA13173AH 2 20 2 IC402 μPDD78F1164 2 23 3 IC503 LC786923W 2 28 4 IC504 AM5810 2 30 5 IC801 TB2946HQ 2 31 6 IC802 BD3702FV 2 37 7 IC901 MC5502 2 32 WIRING DIAGRAM 2 35 BLOCK DIAGRAM 2 37 CIRCUIT DIAGRAMS 2 39 1 MAIN CIRCUIT DIAGRAM 2 39 2 FRONT CIRCUIT DIAGRAM 2 41 3 CDP CIR...

Page 3: ...he 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 whi...

Page 4: ...harges sufficient to damage ESD devices 5 Do not use freon propelled chemicals These can generate electrical charges sufficient to damage ESD de vices 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 comparab...

Page 5: ...108MHz S N Ratio 55dB Distortion 0 7 Usable Sensitivity 12dBμV AM MW Frequency Range 520 1720 or 522 1620 kHz S N Ratio 50dB Distortion 1 0 Usable Sensitivity 28dBμV CD Frequency Response 20Hz 20kHz S N Ratio 80dB Distortion 0 12 Channel Separation 1kHz 55dB AUX Frequency Response 20Hz 20kHz S N Ratio 80dB Distortion 0 1 Channel Separation 1kHz 45dB Max Input Level 1kHz 1 1V Designs and specificat...

Page 6: ... for main CD is displayed in sequence 2 Upgrade program reading Insert update CD in ACC on state and then READING FILE CHK DOWNLORD is displayed in order 3 Upgrade start In order to start upgrade press INT key No2 long more then 2 sec until CHECK CD display on the LCD 4 Upgrade progress display Upgrade is in progress now CHECK CD ERASE WRITE I VRF D VRF 5 Upgrade completion When upgrade finished t...

Page 7: ...nected to the audio set via its shapes matched each other We need power supply for operation of audio set Voltage 12 15V Current Over 2A Before connection between set and power supply adjust voltage level to 15V typically It is okay up to 12V Power Supply has a variety of shapes and capacity of voltage and current At first check these things HOW TO CONNECT AUDIO SET TO POWER SUPPLY ...

Page 8: ...dd and Gnd IC301 15 14 YES NO Checked the Regulator Back up Vdd IC402 30 47 50 99 100 YES NO Checked the Main Micom Back up Vdd IC402 20 51 97 98 YES YES NO Checked the Main Micom Back up Gnd X401 X402 YES NO Checked the Main Micom X tal IC401 IC402 90 NO Checked the Main Micom Reset Q301 R408 IC402 38 YES NO Checked the ACC in SW402 IC402 87 YES NO Checked the detachable switch IC402 53 54 CN901 ...

Page 9: ...e YES IC402 9 10 IC802 25 26 NO Checked the Volume IC control 1A Not available to Key Control OK YES SW902 SW918 YES NO Checked the Tact switch YES CN901 11 13 IC402 53 54 NO Checked the Key line 1B Not available to ANT Motor Type Control OK YES D430 IC301 12 13 IC402 33 NO Checked the ANT control YES 1C ...

Page 10: ...IC802 15 IC402 15 YES NO Checked the E VR Mute Control IC802 1 2 3 4 5 6 7 9 18 19 20 21 22 23 YES YES NO Checked the E VR Signal in out IC801 1 2 8 13 18 24 YES NO Checked the Power IC Ground IC801 23 NO Checked the Power IC Vdd IC801 4 22 IC402 22 32 YES NO Checked the Power IC Control IC801 3 5 7 9 11 12 14 15 17 19 21 23 YES NO Checked the Power IC Signal in out CN302 11 12 13 14 15 16 17 18 Y...

Page 11: ... 14 15 23 32 IC802 15 IC801 22 Q601 Q602 Q603 Q604 Q605 Q606 Q607 Q608 Q609 Q610 YES NO Checked the Mute Contorl YES TU201 8 IC402 7 NO Checked the AF mute 2A No output Beep sound OK YES YES IC402 80 IC802 14 NO Checked the Beep Control 2B ...

Page 12: ...ng 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 RL RL RL 11 9 8 7 5 2 3 17 18 19 21 24 23 12 15 14 1 20 6 RL IN1 IN2 IN3 IN4 13 C1 C1 C1 C1 PRE GND 10 25 22 OUT1 PW GND1 OUT1 OUT2 PW GND2 OUT2 OUT3 PW GND3 OUT3 OUT4 PW GND4 OUT...

Page 13: ...IC901 56 YES NO Checked the LCD Driver Vdd YES IC901 60 NO Checked the LCD Driver Ground YES IC901 57 IC402 79 NO Checked the LCD Driver RESET YES IC901 61 NO Checked the LCD Driver OSC YES IC402 44 CN902 7 IC901 64 NO Checked the LCD Driver data interface YES IC901 1 55 LCD Check the short NO Checked the LCD to LCD Driver line ...

Page 14: ...2 7 Not available to illumination with button OK YES CN302 7 IC301 9 YES NO Checked the Dimmer control input YES IC301 4 NO Checked the LED Vdd YES LD901 LD904 LD919 NO Checked the RED LED 3A ...

Page 15: ...49 YES NO Checked the Dimmer control input YES IC301 4 Q305 CN901 16 NO Checked the LCD Vdd YES Q317 IC402 41 NO Checked the LCD Vdd control YES LD902 LD903 NO Checked the LED 3C Don t moved Level dancing bar OK YES IC802 17 IC402 57 NO Checked the Level Meter Signal Input YES 3B ...

Page 16: ... 10 14 YES NO Checked the Tuner Vdd YES IC402 40 Q307 IC301 11 NO Checked the Tuner Vdd control YES TU201 3 7 12 16 NO Checked the Tuner Ground YES TU201 14 15 IC402 34 36 NO Checked the I2C data YES TU201 1 2 NO Checked the RF signal in YES TU201 8 IC402 7 NO Checked the Mute Control YES TU201 5 IC402 8 NO Checked the SD level RDS model ...

Page 17: ...Checked the RDS data 4B Tuner no sound OK YES TU201 10 11 IC802 5 6 YES NO Checked the Tuner Signal out YES TU201 8 IC402 7 NO Checked the AF mute YES See the Sound Error correction Process NO Checked the E VR Power AMP 4A Not available to RDS function OK YES TU201 19 20 IC402 5 6 NO Checked the RDS data YES 4C ...

Page 18: ...60 72 81 123 143 NO Checked the CD DSP Ground YES IC504 7 8 20 NO Checked the Motor DRV VDD YES IC504 88 NO Checked the CD DSP Reset YES X501 NO Checked the CD DSP X tal YES CN506 2 NO Checked the Disc in load switch YES CN520 19 21 NO Checked the Loading Motor Control YES CN506 1 NO Checked the 12 8cm sens switch Fig 1 2 Fig 3 4 Fig 1 2 5A 5B 5C ...

Page 19: ...IC503 38 IC504 15 16 NO Checked the focus Control YES IC503 17 NO Checked the focus error level out FE Mon YES CN520 15 NO Checked the PLL locking FSEQ YES IC503 8 NO Checked the RF signal out check Fig 5 Fig 1 2 Fig 3 4 Fig 10 11 Fig 5 Fig 12 Fig 9 YES IC503 41 IC504 11 12 NO Checked the spindle motor Control YES IC503 40 IC504 13 14 NO Checked the SLED Control YES IC503 39 IC504 17 18 NO Checked...

Page 20: ...2 13 Fig 3 4 CD no sound OK YES IC503 140 141 NO Checked the DSP signal out YES No ejected the CD OK YES IC402 54 NO Checked the Eject key YES CN520 19 21 NO Checked the Loading Motor Control YES 5B 5C ...

Page 21: ... CORRECTION FLOW CHART AUX no sound OK Something wrong With the AUX YES JK901 CN901 6 10 L901 L902 R603 R604 NO Checked the AUX Signal input YES See the Sound Error correction Process NO Checked the E VR Power AMP YES ...

Page 22: ...27 LOADING S W 12 8 S W CHUCKING S W LIMIT S W Fig 3 MOTOR CONTROL SIGNAL FOR LOADING CN520 PIN19 CN520 PIN21 CN506 PIN9 CN506 PIN10 LO LO LO LO REW REW FEW FEW Fig 4 MOTOR CONTROL SIGNAL FOR UNLOADING CN520 PIN19 CN520 PIN21 CN506 PIN9 CN506 PIN10 Fig 5 FOCUS CONTROL SIGNAL IC503 PIN38 IC503 PIN17 IC504 PIN15 IC504 PIN16 FDO FE RFMON F F Fig 6 TRACKING CONTROL SIGNAL IC503 PIN39 IC503 PIN25 IC504...

Page 23: ... IC503 PIN40 IC504 PIN13 IC504 PIN14 SLOUT SL SL Fig 9 MD RFOUT LD CN519 PIN 15 IC503 PIN 8 CN519 PIN 16 MD RFOUT LD Fig 10 DI DO CL CE IC503 DO PIN87 IC503 DI PIN86 IC503 CL PIN85 IC503 CE PIN84 Fig 11 DI DO CL CE Detail IC503 DO PIN87 IC503 DI PIN86 IC503 CL PIN85 IC503 CE PIN84 Fig 12 FSEQ WRQ CN520 PIN24 CN520 PIN25 ...

Page 24: ...1 0 2 0 3 6 56 4 5 5 6 56 6 13 96 7 6 54 8 0 01 9 6 53 10 8 05 11 6 47 12 6 51 13 0 14 6 54 15 6 54 16 6 58 17 6 58 18 0 19 6 55 20 13 97 21 6 52 22 4 97 23 6 56 24 0 25 1 24 1 0 2 0 3 0 4 0 5 0 28 6 0 28 7 0 8 4 98 9 4 96 10 0 11 0 12 0 13 0 14 5 05 15 5 01 16 0 17 5 06 18 0 19 0 063 20 2 5 1 6 56 2 6 57 3 6 53 4 6 54 5 0 6 0 7 0 8 6 54 9 6 546 10 13 47 11 0 12 6 53 13 6 58 14 14 05 15 0 16 14 1 ...

Page 25: ...ge detect TSD VREF CDOUT VREF EXTOUT VBUP DSPOUT CTL 2 2 5V CTL 3 2 5V CTL 4 2 5V 15 FREG F RFREG3 FREG B 13 12 11 10 9 8 7 6 5 4 3 2 1 14 3 5V DBUP CBUP 100uF CVDD 10uF CDSP 10uF CAUDIO 10uF CCD 0 1uF CEXT 10uF CILM 0 1uF CFREG 10uF QFREG RFREG1 RFREG2 DEXT1 DEXT2 C1 100uF C2 0 1uF INTERNAL BLOCK DIAGRAM OF ICs ...

Page 26: ...mal shut down prevents thermal damage to the IC All outputs except VDD pin14 and FREG pin2 3 are switched off when the circuit operates revert to the original state when the tem perature drops to a certain level Note3 Overvoltage protection circuit The overvoltage protection circuit surge protector turns off all outputs without Vdd when VB voltage is more than about 21V And the overvoltage protect...

Page 27: ...0 ANO0 P111 ANO1 AV REF0 EV DD0 V DD EV SS0 V SS REGC P121 X1 P122 X2 EXCLK FLMD0 P123 XT1 P124 XT2 RESET P40 TOOL0 P41 TOOL1 P42 TI04 TO04 P43 SCK01 P44 SI01 P45 SO01 P46 INTP1 TI05 TO05 P47 INTP2 P120 INTP0 EXLVI P60 SCL0 P61 SDA0 P62 P63 P31 TI03 TO03 INTP4 P64 RD P65 WR0 P66 WR1 P67 ASTB P77 EX23 KR7 INTP11 P76 EX22 KR6 INTP10 P75 EX21 KR5 INTP9 P74 EX20 KR4 INTP8 P73 EX19 KR3 P72 EX18 KR2 P71...

Page 28: ...EX2 DRV_MUTE O I O O CMOS Deck driver IC mute 24 P83 EX3 FEW O I O O CMOS Loading motor loading 25 P84 EX4 REW O I O O CMOS Loading motor unloading 26 P85 EX5 CDP_OPTION1 I I O I 27 P86 EX6 CDP_OPTION2 I I O I 28 P87 EX7 CHUCK_SW I I O I 29 P30 INTP3 RTC1HZ INN I I O I Deck inner SW 30 EVDD1 EVDD 31 P50 EX8 12 8 I I O O CMOS Deck 12cm disc detect SW 32 P51 EX9 POWERIC_MUTE O I O O CMOS To Power am...

Page 29: ...OTH 72 P02 SO10 TXD1 BLUETOOTH_TX O I O O CMOS Data output for BLUETOOTH 73 P01 TO00 LIGHT_CONTROL O I O O CMOS KNOBLIGHT COLOR control output 74 P00 TI00 LCD_CE O I O O CMOS Data enable output to LCD drv 75 P145 TI07 TO07 N C I O I 76 P144 SO20 TxD2 USB_TX O I O O CMOS DATA input for USB 77 P143 SI20 RxD2 SDA2 USB_RX I I O I Data output for USB 78 P142 SCK20 SCL2 USB_SW I I O I 79 P141 PCLBUZ1 IN...

Page 30: ...2 23 3 IC503 LC786923W 3 1 PIN CONFIGURATION ...

Page 31: ...2 24 3 2 BLOCK DIAGRAM ...

Page 32: ...2 25 3 3 PIN DESCRIPTION ...

Page 33: ...2 26 ...

Page 34: ...2 27 ...

Page 35: ... BIAS OPIN4 OPIN4 MUTE GND VO3 VO3 OPOUT4 OPIN3 OPIN3 OPOUT3 POWVCC34 VO4 VO4 8 9 10 11 12 13 14 1 2 3 4 5 6 7 21 20 19 18 17 16 15 28 27 26 25 24 23 22 LOADING PRE FWD REV x 3 POWER SAVE 7 5K PREVCC PRE LOADING 16K 16K 7 5K POWVCC12 CH1 CH2 10K LEVEL SHIFT _ 10K 10K 10K 10K 10K LEVEL SHIFT 10K 10K _ 10K 10K 10K 10K 10K 10K LEVEL SHIFT 10K 10K _ POWVCC34 CH3 CH4 CH1 CH4 MUTE 7 5K 16K 7 5K 16K LEVE...

Page 36: ...H2 12 VO2 Not inverted output of CH2 13 VO1 Inverted output of CH1 14 VO1 Not inverted output of CH1 15 VO4 Not inverted output of CH4 16 VO4 Inverted output of CH4 17 VO3 Not inverted output of CH3 18 VO3 Inverted output of CH3 19 GND Substrate ground 20 POWVCC34 Power unit power supply input terminal CH3 CH4 21 MUTE Input for mute control 22 OPOUT3 Output of CH3 OP AMP 23 OPIN3 Inverting input o...

Page 37: ...VCC1 VCC2 TAB Ripple C2 B C3 C5 9 Out1 11 C1 8 7 PW GND1 Out1 IN1 5 Out2 12 C1 2 3 PW GND2 Out2 IN2 17 Out3 15 18 19 PW GND3 Out3 IN3 21 Out4 14 C1 24 23 PW GND4 Out4 IN4 13 16 C1 C6 4 Stby 25 22 Mute C4 R1 Play Mute RL RL RL RL Pre GND AC GND Offset short ...

Page 38: ... of 1ch 12 EN2 E negative input terminal of 2ch 13 EP2 E positive input terminal of 2ch 14 MIN Mixing input terminal Terminal Terminal Description No Name 15 MUTE External compulsory mute terminal 16 LRST Level meter reset terminal 17 LOUT Output terminal for Level meter 18 OUTS2 Subwoofer output terminal of 2ch 19 OUTS1 Subwoofer output terminal of 1ch 20 OUTR2 Rear output terminal of 2ch 21 OUTR...

Page 39: ...2 32 7 IC901 MC5502 7 1 PIN CONFIGURATION 7 2 BLOCK DIAGRAM ...

Page 40: ...O LCD Segment output pins 52 SEG52 COM0 O LCD Segment output pin or LCD Common output pin SEG52 in 1 3 Duty use COM0 in 1 4 Duty use 53 55 COM1 COM3 O LCD Common output pins 57 INH I Display off control input pin INH VSS Display forced off INH VDD Display on 58 59 VLC1 VLC2 I O LCD power supply 61 OSC I O Oscillator output pin 62 CE I Chip enable input pin 63 SCK I Shift clock input pin 64 SI I Se...

Page 41: ...2 34 MEMO ...

Page 42: ...WIRING DIAGRAM 2 35 2 36 ...

Page 43: ...BLOCK DIAGRAM 2 37 2 38 ...

Page 44: ...CIRCUIT DIAGRAMS 1 MAIN CIRCUIT DIAGRAM 2 39 2 40 ...

Page 45: ...2 FRONT CIRCUIT DIAGRAM 2 41 2 42 ...

Page 46: ...3 CDP CIRCUIT DIAGRAM A 1 2 3 4 5 6 7 8 9 10 11 12 B C D E F G H I J K L M N O P Q R S T 2 43 2 44 ...

Page 47: ...PRINTED CIRCUIT BOARD DIAGRAMS 1 MAIN P C BOARD TOP VIEW BOTTOM VIEW 2 45 2 46 ...

Page 48: ...2 FRONT P C BOARD TOP VIEW BOTTOM VIEW 2 47 2 48 ...

Page 49: ...3 CDP P C BOARD TOP VIEW BOTTOM VIEW 2 49 2 50 ...

Page 50: ...297 A41 458 458 A26 292 A46 A43 A45 274 453 451 451 298 294 258 255 257 254 259 256 252 253 457 251 454 A42 250 CDP MAIN 279 281 282 LCD901 260 284 276 FRONT Accessory Loc No Loc No Loc No Loc No 801 818 835 850 285 280 290 451 269 263 268 262 270 264 265 266 267 261 A50 3 1 3 2 ...

Page 51: ...2 MECHANISM PICK UP SECTION 2 1 A26 A03 3 3 3 4 ...

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