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LG DR7400, Service Manual

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LG DR7400 Service Manual Download Page 14

3-4

No 12V

Is the Vcc(13.5V) sup-
plied to IC157 Pin1?

Is the IC157 Pin4 ‘H’?

Check or Replace 
the IC157

YES

Check the PWR CTL
“H” signal from µ-com 

Check or Replace 
the D127

NO

NO

YES

No 12VL

Is the Vcc(13.5V) sup-
plied to IC152 Pin1?

Is the IC152 Pin4 ‘H’?

YES

Check or Replace 
the IC152

YES

Check or Replace 
the D127

NO

Check the PWR CTL
“H” signal from µ-com 

NO

No 33V

Is the Vcc(33V) sup-
plied to Q161 Emitter?

Is the ZD126 normal?

Is the Q161 Base ‘H’?

YES

Replace the ZD126

Replace the D126

NO

NO

Check the PWR CTL
“H” signal from µ-com 

NO

YES

Check or Replace 
the Q161

YES

Summary of Contents for DR7400

Page 1: ...SERVICE MANUAL LG DR 7400 MODEL ...

Page 2: ...CONTENTS SECTION 1 SUMMARY SECTION 2 CABINET MAIN CHASSIS SECTION 3 ELECTRICAL SECTION 4 REPLACEMENT PARTS LIST ...

Page 3: ...T SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS 1 2 SERVICING PRECAUTIONS 1 3 General Servicing Precautions Insulation Checking Prodedure Electrostatically Sensitive Devices SERVICE INFORMATION FOR EEPROM IC SETTING 1 4 SPECIFICATIONS 1 5 ...

Page 4: ...lder splashes or sharp solder points Be certain to remove all loose foreign par ticles 4 Check for physical evidence of damage or deterioration to parts and compo nents for frayed leads or damaged insulation including the AC cord and replace if necessary 5 No lead or component should touch a high current device or a resistor rated at 1 watt or more Lead tension around protruding metal surfaces mus...

Page 5: ...ts including Metal pan els Input terminals Earphone jacks etc Electrostatically Sensitive ES Devices Some semiconductor solid state devices can be damaged easily by static electricity Such components commonly are called Electrostatically Sensitive ES Devices Examples of typical ES devices are integrated circuits and some field effect transistors and semiconductor chip components The following tech...

Page 6: ...rding format Sampling frequency 48kHz Compression format Dolby Digital PLAYBACK Frequency response DVD PCM 48 kHz 8 Hz to 22 kHz CD 8 Hz to 20 kHz DVD PCM 96 kHz 8 Hz to 44 kHz Signal to noise ratio More than 100 dB AUDIO OUT connector Harmonic distortion Less than 0 008 THD AUDIO OUT connector Dynamic range More than 95 dB AUDIO OUT connector INPUTS ANTENNA IN Antenna input 75 ohms VIDEO IN 1 0 V...

Page 7: ...2 1 SECTION 2 CABINET MAIN CHASSIS CONTENTS EXPLODED VIEWS 2 2 1 Cabinet and Main Frame Section 2 2 2 Deck Mechanism Section DR 06 MAIN PCB 2 3 3 Packing Accessory Section 2 4 ...

Page 8: ...inet and Main Frame Section 275 275 452 452 280 255 274 463 463 468 300 465 250 272 260 261 465 465 261 261 261 320 265 468 463 463 463 463 283 452 A50 A43 A48 A44 A47 A60 A52 A000 277 262 TU701 OPTIONAL PART A 5 4 3 2 1 B C D ...

Page 9: ...1 1025 1025 1030 1432 1029 1432 1021 1432 1432 1032 1033 1011 1019 1009 1020 1019 1012 1013 1439 1014 1016 1015 1017 1018 1018A 1018B 1018E 1435 1018E 1018D 1006 1436 1024 1433 1029 1027 1027 1026 1003 1002 A004 A002 A000 A60 1437 1005 1434 1434 MAIN PCB ...

Page 10: ... Coaxial Plug Ass y 1Way Plug Ass y 2Way Bag Packing Remote Control Instruction Ass y Packing Box 806 804 803 811 812 FLAT CABLE 822 801 900 802 803 810 CABLE ASS Y 821 SCART CABLE OPTIONAL PART 3 Packing Accessory Section ...

Page 11: ...PEG CIRCUIT DIAGRAM 3 16 3 DSP CIRCUIT DIAGRAM 3 18 4 RF CIRCUIT DIAGRAM 3 20 5 TUNER MPX ADC DAC JACK CIRCUIT DIAGRAM 3 22 6 FRONT JACK CIRCUIT DIAGRAM 3 24 7 KEY CIRCUIT DIAGRAM 3 26 8 TIMER CIRCUIT DIAGRAM 3 28 WAVEFORMS 3 30 CIRCUIT VOLTAGE CHART 3 32 PRINTED CIRCUIT DIAGRAMS 3 38 1 MAIN P C BOARD TOP SIDE 3 38 2 MAIN P C BOARD BOTTOM SIDE 3 40 3 I O P C BOARD 3 42 4 JACK P C BOARD 3 42 5 KEY ...

Page 12: ...O YES YES YES YES YES YES YES Replace the R101 Is the D102 normal Check or Replace the D102 Replace the D124 Replace the IC103 Replace the IC102 Replace the D123 Replace the D126 Replace the D127 Is the D124 normal Is there about 2 5V at the IC103 Pin1 Is Vcc 9V 18V supplied to IC101 Pin2 Is the IC102 normal Is the D123 normal Is the D126 normal Is the D127 normal Power in Main PCB is short 1 Powe...

Page 13: ...IC153 Pin1 Check or Replace the IC153 YES Check or Replace the D123 NO No 5 0V Is the Vcc 5 3V sup plied to IC156 Pin1 Is the IC156 Pin4 H Check or Replace the IC156 YES Check the PWR CTL H signal from µ com Check or Replace the D123 NO NO YES No 5 0VA Is the Vcc 5 3V sup plied to IC155 Pin1 Is the IC155 Pin4 H YES Check or Replace the IC155 YES Check or Replace the D123 NO Check the PWR CTL H sig...

Page 14: ...o 12VL Is the Vcc 13 5V sup plied to IC152 Pin1 Is the IC152 Pin4 H YES Check or Replace the IC152 YES Check or Replace the D127 NO Check the PWR CTL H signal from µ com NO No 33V Is the Vcc 33V sup plied to Q161 Emitter Is the ZD126 normal Is the Q161 Base H YES Replace the ZD126 Replace the D126 NO NO Check the PWR CTL H signal from µ com NO YES Check or Replace the Q161 YES ...

Page 15: ...layed at POWER ON Check X501 Check IC501 and other Circuits Check SMPS IC501 238 237 27M OSC_IN IC501 198 CVBS_out Check IC709 8 29 EUI_V_OUT DRIVE not recognized Check DRIVE power 5V 12V Check ATAPI interface connector CN304 2 SYSTEM CIRCUIT ...

Page 16: ...gnal normal Check JK703 2 Signal wave Check IC301 IC501 209 210 212 213 Audio signal normal IC503 5 6 SCL SDA signal normal Check IC501 circuits Concerned audio Check IC503 IC501 SCL SDA signal YES NO IC715 7 8 SCL SDA signal normal Check IC715 and Other circuits Check IC5715 SCL SDA signal ...

Page 17: ... When playing Disc No audio output IC701 22 pin ITU_RESET_L is High Check IC701 and other circuits YES NO YES NO YES NO X701 18 432MHz Clock is Okay YES NO Check X701 C748 C749 Check the 5 2V and R724 IC701 2 pin SIF signal is Okay YES NO Check TUNER and other circuits No Tuner Audio Output and other circuit ...

Page 18: ... pin DISC PLAY Audio Out is normal Check When Playing Disc No Audi o Output IC709 21 25 pin L1 IC709 22 26 pin L2 Audio output is normal YES NO YES NO YES NO YES NO Check When RCA Input No Audio Output Check SCART Jack JK701 JK702 Check signal path from IC709 to JK701 JK702 Check IC709 and other circuits 3 8 ...

Page 19: ...IC708 1 14 pin No Audio Signal input YES NO IC714 10 12 pin Audio signal okey YES NO Audio signal path from front AV to IC708 and check CSI03 2 3pin IC709 23 27 pin Audio Signal is okey YES NO Check IC709 and other circuit Check signal path from IC709 IC714 Check IC706 When L3 Input PIM02 PMI02 18 19 20 21pin are okay YES NO Check Connector PIM02 PMI02 ...

Page 20: ......

Page 21: ...Block Diagram RECTIFIER LINE FILTER SWITCHING IC TRANS FEED B RECTIFIER 5V AC100 240V PWR CTL REG 12V REG 12V RECTIFIER 3 3VA REG 33V 12V 12VL 5VL 5V 5VA 3 3V RECTIFIER 33VA RECTIFIER 12VA REG 12V REG 5V REG 5VA 3 3VA LPF LPF LPF LPF ...

Page 22: ... Con CS5340 AUDIO A D Con CS4351 DAC AMP CS4351 DAC AMP MM1443 AV S W 4in 3out Canal Plus V1 Tu E1 E2 Buffer V2 Tu E1 Ext 6dB 75Ω Driver V3 E2 Ext 6dB 75Ω Driver Audi o In Out 2Vrms at 5 65 Vdc Tu V2 V3 E2 E1 Ext FS REAR REAR SCART 1 SCART 1 SCART 2 SCART 2 EU1_V_IN EU1_V_OUT EU2_V_IN EU2_V_OUT V1 75Ω 75Ω 75Ω 75Ω SCART_H LOUT2 ROUT2 220 220 EU2_A_OUT_L EU2_A_OUT_R E2 L E2 R EU2_A_IN_L EU2_A_IN_R L...

Page 23: ...HIS CHASSIS UNDER NO CIR CUMSTANCES SHOULD THE ORIGINAL DESIGN BE MODIFIED OR ALTERED WITHOUT PERMISSION FROM THE LG ELECTRONICS CORPORATION ALL COMPONENTS SHOULD BE REPLACED ONLY WITH TYPES IDENTICAL TO THOSE IN THE ORIGINAL CIR CUIT SPECIAL COMPONENTS ARE SHADED ON THE SCHEMATIC FOR EASY IDENTIFICATION THIS CIRCUIT DIAGRAM MAY OCCASIONALLY DIF FER FROM THE ACTUAL CIRCUIT USED THIS WAY IMPLEMENTA...

Page 24: ...2 MPEG CIRCUIT DIAGRAM A B C D E F G H I J K L M N O P Q R S T 3 16 3 17 ...

Page 25: ...3 18 3 19 3 DSP CIRCUIT DIAGRAM A B C D E F G H I J K L M N O P Q R S T ...

Page 26: ...4 RF CIRCUIT DIAGRAM A B C D E F G H I J K L M N O P Q R S T 3 20 3 21 ...

Page 27: ...3 22 3 23 5 TUNER MPX ADC DAC JACK CIRCUIT DIAGRAM A B C D E F G H I J K L M N O P Q R S T ...

Page 28: ...A B C D E F G H I J K L M N O P Q R S T 3 24 3 25 6 FRONT JACK CIRCUIT DIAGRAM ...

Page 29: ...3 26 3 27 A B C D E F G H I J K L M N O P Q R S T 7 KEY CIRCUIT DIAGRAM ...

Page 30: ...3 28 3 29 8 TIMER CIRCUIT DIAGRAM A B C D E F G H I J K L M N O P Q R S T ...

Page 31: ...3 30 3 31 WAVEFORMS X201 33 86MHz X501 27MHz X502 32 768KHz IC501 248 Y_IN IC502 SDRAM_CLK IC501 227 SPDIF IC701 57 SIF_OUT IC504 28 FLASH_OE IC504 11 FLASH_WE ...

Page 32: ... 11 1 15 199 1 14 1 11 1 18 200 0 00 0 00 0 00 201 1 15 1 11 1 22 202 1 15 1 14 1 13 203 2 49 2 49 2 48 204 1 15 1 20 1 05 205 1 15 1 15 1 12 206 0 00 0 00 0 00 207 1 26 1 28 1 33 208 1 80 1 75 1 62 209 0 00 0 00 0 00 210 1 24 1 23 1 23 211 1 25 1 25 1 24 212 1 17 1 14 1 09 213 1 16 1 13 1 09 214 1 17 1 14 1 13 215 1 19 1 17 1 15 216 1 22 1 21 1 21 IC203 1 2 49 2 49 2 48 2 1 15 1 11 1 15 3 2 49 2 ...

Page 33: ...0 5 20 64 0 00 0 00 0 00 65 0 00 0 00 0 47 66 5 16 5 16 5 16 67 0 00 0 00 0 00 68 0 00 0 00 0 00 69 0 00 0 00 0 00 70 0 00 0 00 0 00 71 0 00 0 00 0 00 72 0 00 0 00 0 00 73 0 00 0 00 0 00 74 2 85 2 84 2 84 75 2 85 2 84 2 84 76 0 00 0 00 0 00 77 5 20 5 19 5 19 78 4 25 4 24 4 24 79 0 00 0 00 0 00 80 2 86 2 85 2 85 81 0 00 0 00 0 00 82 0 00 0 00 0 00 83 0 00 0 00 0 00 84 2 84 2 84 2 84 85 2 85 2 84 2 ...

Page 34: ...17 26 0 00 0 00 0 00 27 0 00 0 00 0 00 28 4 63 4 63 4 63 30 0 00 0 00 0 00 31 0 00 0 00 0 00 EE PB REC MODE PIN NO 32 0 00 0 00 0 00 33 0 66 0 72 0 68 34 0 67 0 71 0 66 35 0 00 0 00 0 00 36 5 17 5 17 5 17 37 2 56 2 52 2 55 38 2 35 2 55 2 43 39 0 00 0 00 0 00 40 2 03 2 04 2 01 41 2 54 2 52 2 52 42 0 00 0 00 0 00 43 3 58 3 42 3 58 44 4 90 4 90 4 90 IC706 1 5 19 5 19 5 19 2 1 53 1 53 1 53 3 1 52 1 52...

Page 35: ...3 38 3 39 PRINTED CIRCUIT DIAGRAMS 1 MAIN P C BOARD TOP SIDE ...

Page 36: ...3 40 3 41 2 MAIN P C BOARD BOTTOM SIDE ...

Page 37: ...3 42 3 43 3 I O P C BOARD TOP SIDE 4 JACK P C BOARD BOTTOM SIDE ...

Page 38: ...3 44 3 45 5 KEY P C BOARD 6 FRONT P C BOARD 7746AA 8 POWER P C BOARD LOCATION GUIDE ...

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