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SERVICE MANUAL

This Service Manual is for the 
LT850-M22 (A0C70EP) / LT851-M22 (A0C71EP) model.
For the LT850-M22 (A0C70EP) / LT851-M22 (A0C71EP) model, the letter 
(A0C70EP) / (A0C71EP) is printed on the Serial Number Label on the back 
of the unit. Refer to the Serial Number Label below.

Serial No. Label

Serial No. Label

"A0C70EP"

"A0C71EP"

22

 COLOR LCD TELEVISION

LT850-M22 / LT851-M22

Summary of Contents for LT850-M22 - SERVICE

Page 1: ...EP model For the LT850 M22 A0C70EP LT851 M22 A0C71EP model the letter A0C70EP A0C71EP is printed on the Serial Number Label on the back of the unit Refer to the Serial Number Label below Serial No Lab...

Page 2: ...ze the LCD Television 6 1 Firmware Renewal Mode 7 1 Troubleshooting 8 1 Block Diagrams 9 1 Schematic Diagrams CBA and Test Points 10 1 Waveforms 11 1 Wiring Diagram 12 1 Exploded View 13 1 Mechanical...

Page 3: ...iption Condition Unit Nominal Limit 1 RECEIVED FREQ RANGE 60dBm 45ch 1 2 kHz kHz 1000 900 500 167 2 INPUT DYNAMIC RANGE mix max c 1 VHF HIGH 8ch UHF 45ch dBuV dBuV 25 101 25 101 28 98 29 98 d 2 VHF HI...

Page 4: ...ghtly below these specifications Limit specifications represent the absolute worst condition that still might be considered acceptable In no case should a unit fail to meet limit specifications Descri...

Page 5: ...terminal screw and if applicable to the coaxial connector If the measured resistance is less than 1 0 megohm or greater than 5 2 megohm an abnormality exists that must be corrected before the instrum...

Page 6: ...near thermally hot parts be sure that leads and components do not touch thermally hot parts c the AC supply d high voltage and e antenna wiring Always inspect in all areas for pinched out of place or...

Page 7: ...PVC tubing 3 Spacers 4 Insulators for transistors E When replacing AC primary side components transformers power cord etc wrap ends of wires securely about the terminals before soldering F Observe tha...

Page 8: ...and externally exposed accessible parts RF terminals an tenna terminals video and audio input and output ter minals microphone jacks earphone jacks etc Measuring Method Power ON Insert load Z between...

Page 9: ...the flat pack IC is fixed with glue to the CBA when removing entire flat pack IC first apply soldering iron to center of the flat pack IC and heat up Then remove glue will be melted Fig S 1 6 4 Relea...

Page 10: ...ins of the flat pack IC you can remove it easily Fig S 1 3 2 Affix the wire to a workbench or solid mounting point as shown in Fig S 1 5 3 While heating the pins using a fine tip soldering iron or hot...

Page 11: ...occur due to a potential difference caused by electrostatic charge during unpacking or repair work 1 Ground for Human Body Be sure to wear a grounding band 1 M that is properly grounded to remove any...

Page 12: ...cking Tabs L 2 5 Refer to the following Reference Notes in the Table Step Loc No Part Removal Fig No Remove Unhook Unlock Release Unplug Unclamp Desolder Note 1 Stand Assembly D1 3 S 1 2 Rear Cabinet...

Page 13: ...4 2 A0C72_73DC 2 Rear Cabinet 1 Stand Assembly S 3 S 2 S 2 S 2 S 2 S 2 S 4 S 5 S 1 Fig D1...

Page 14: ...Main CBA 9 Digital Main CBA Unit 10 LCD Module Assembly 11 Speaker 11 Speaker 12 Junction CBA 13 Function CBA 14 Front Cabinet S 11 S 13 S 13 S 7 S 7 S 7 S 7 S 7 S 15 S 14 S 6 S 9 S 16 S 16 S 12 H 1 S...

Page 15: ...ital Main CBA Unit Jack CBA CN3704 CN3702 CN3703 CN3701 CN3901 Junction CBA Function CBA To Speaker To Speaker To LCD Module Assembly CN101B CN102B CN101A CN452 CN401 CN404 CN403 CN402 CN1550 CN1650 C...

Page 16: ...stments unless the proper equipment is available Test Equipment Required 1 NTSC Pattern Generator Color Bar W White Window Red Color Dot Pattern Gray Scale Monoscope Multi Burst 2 Remote control unit...

Page 17: ...he LCD Panel surface 3 Enter the Service mode 4 To enter the VCOM 2 adjustment mode press 3 button on the remote control unit To enter the VCOM 1 adjustment mode press 2 button on the remote control u...

Page 18: ...de 5 CUTOFF Press 1 button to select COR for Red Cutoff adjustment Press 3 button to select COB for Blue Cutoff adjustment DRIVE Press 4 button to select DR for Red Drive adjustment Press 6 button to...

Page 19: ...the service mode Refer to page 5 1 To cancel the service mode press button on the remote control unit 3 Press button on the remote control unit to initialize the LCD television 4 INITIALIZED will app...

Page 20: ...h digit of the file name indicate the size of TV If the size of your TV and the file name were not the same you must change the file name Update procedure 1 Plug in the AC power cord 2 Press button on...

Page 21: ...ndary circuit and service it if defective Check the presence that the primary component is leaking or shorted and service it if defective Check the presence that the rectifying diode or circuit is sho...

Page 22: ...of Q605 Check D634 and their periphery circuit and service it if defective Replace Q605 Is approximately 7 5V voltage supplied to the collector of Q616 No AL 7 5V is not outputted FLOW CHART NO 7 Yes...

Page 23: ...10V voltage supplied to the anode of D613 Is approximately 10V voltage supplied to the base of Q611 Yes Is approximately 13V voltage supplied to the base of Q615 No Check D664 and their periphery circ...

Page 24: ...C614 and their periphery circuit and service it if defective Check D612 D620 C613 and their periphery circuit and service it if defective Check Q607 Q610 D639 P ON H2 line and their periphery circuit...

Page 25: ...RGB input Are the video signals outputted to the specific terminal Check the luminance signal line and service it if defective Check the chrominance signal line and service it if defective Check the R...

Page 26: ...is not outputted normally Audio input terminals FLOW CHART NO 20 Check the line between Pin 16 18 of CN403 and Pin 4 5 of TU10 and TU10 Tuner Unit and service it if defective Are the DIF signals outpu...

Page 27: ...ON H1 PROTECT1 P ON H2 P ON H1 AH2 JUNCTION CBA CN102B KEY IN1 6 6 CN102A CN403 CN3703 AH27 BACKLIGHT ADJ IC3102 SERIAL FLASH MEMORY CLOCK DATA IN D11 B10 6 5 E23 TUNER CLK TUNER DATA CN403 CN3703 CN...

Page 28: ...OUT2 4 DIF OUT1 5 TUNER UNIT IF AGC 6 CN403 CN3703 DIF OUT2 16 16 IF AGC 20 20 DIF OUT1 18 18 VIDEO IN RGB VIDEO IN VIDEO OUT VIDEO R VIDEO G VIDEO B TO DIGITAL SIGNAL PROCESS BLOCK DIAGRAM S VIDEO Y...

Page 29: ...3 HEADPHONE R 4 4 HEADPHONE DET 2 2 CN3703 CN403 AMP L OUT 10 10 AMP R OUT 8 8 AUDIO MUTE 12 12 TO SYSTEM CONTROL BLOCK DIAGRAM WF7 RGB AUDIO L OUT 6 6 RGB AUDIO R OUT 7 7 8 IC801 AUDIO AMP IC3802 OP...

Page 30: ...TMDS D0 TMDS D1 TMDS D1 TMDS D2 TMDS D2 TMDS CLOCK TMDS CLOCK SDA SCL F2 F1 G2 G1 H2 H1 E2 E1 AG10 AJ8 B1 B2 C1 C2 D1 D2 A1 A2 AF10 AE11 TMDS CLOCK TMDS CLOCK DEMODULATOR MPEG DECODER DEMODU ADC DAC...

Page 31: ...3 Q1024 Q1600 T1700 DRIVE Q1005 Q1007 Q1008 DRIVE OSC PWM CONTROL LOGIC VCC DTC CURRENT CONTROL SWITCH CURRENT CONTROL SWITCH Q1700 CURRENT CONTROL SWITCH 11 8 5 6 15 3 4 12 VREF 14 16 2 1 SW SW 7 5V...

Page 32: ...circuit to fail HOT COLD MAIN CBA HOT CIRCUIT BE CAREFUL Q602 SWITCHING CONTROL 1 4 3 2 IC605 T601 3 LINE FILTER L601 AC601 AC CORD BRIDGE RECTIFIER D602 D604 D605 D607 1 2 16 15 14 13 12 11 10 9 5 6...

Page 33: ...itute replacement parts that do not have the same safety characteristics as specified in the parts list may create shock fire or other hazards Notes 1 Do not use the part number shown on these drawing...

Page 34: ...ed 2 To maintain original function and reliability of repaired units use only original replacement parts which are listed with their part numbers in the parts list section of the service manual 4 Volt...

Page 35: ...table power supply circuit is used in this unit If Main Fuse F601 is blown check to see that all components in the power supply circuit are not defective before you connect the AC plug to the AC power...

Page 36: ...10 4 A0C70SCM2 Main 2 Schematic Diagram...

Page 37: ...10 5 A0C70SCM3 Main 3 Schematic Diagram...

Page 38: ...10 6 A0C70SCM4 Main 4 Schematic Diagram...

Page 39: ...10 7 A0C70SCF Function Junction Schematic Diagram...

Page 40: ...10 8 Jack Schematic Diagram A0C70SCJ...

Page 41: ...Main 1 Schematic Diagram The order of pins shown in this diagram is different from that of actual IC3301 IC3301 is divided into six and shown as IC3301 1 7 IC3301 7 7 in this Digital Main Schematic D...

Page 42: ...l Main 2 Schematic Diagram The order of pins shown in this diagram is different from that of actual IC3301 IC3301 is divided into six and shown as IC3301 1 7 IC3301 7 7 in this Digital Main Schematic...

Page 43: ...l Main 3 Schematic Diagram The order of pins shown in this diagram is different from that of actual IC3301 IC3301 is divided into six and shown as IC3301 1 7 IC3301 7 7 in this Digital Main Schematic...

Page 44: ...l Main 4 Schematic Diagram The order of pins shown in this diagram is different from that of actual IC3301 IC3301 is divided into six and shown as IC3301 1 7 IC3301 7 7 in this Digital Main Schematic...

Page 45: ...l Main 5 Schematic Diagram The order of pins shown in this diagram is different from that of actual IC3301 IC3301 is divided into six and shown as IC3301 1 7 IC3301 7 7 in this Digital Main Schematic...

Page 46: ...l Main 6 Schematic Diagram The order of pins shown in this diagram is different from that of actual IC3301 IC3301 is divided into six and shown as IC3301 1 7 IC3301 7 7 in this Digital Main Schematic...

Page 47: ...l Main 7 Schematic Diagram The order of pins shown in this diagram is different from that of actual IC3301 IC3301 is divided into six and shown as IC3301 1 7 IC3301 7 7 in this Digital Main Schematic...

Page 48: ...3 3V J226 C1602 J227 C1603 D1003 JS400 C1604 D1004 POW for 1 1V J229 R311 C1605 D1005 D1006 R1002 CN103 D1007 D660 R1004 R1005 P ON 5V J230 SP L J231 GND J234 D1010 D1011 CN301 VDACOUT1 J236 D1012 15V...

Page 49: ...07 Q609 D510 D511 L405 Q801 L406 Q802 L407 D513 Q803 L408 Q610 Q804 Q611 Q612 Q613 Q614 Q615 BC401 L601 BC402 Q616 BC601 BC602 BC603 BC604 BC605 BC801 BC802 D151 J1001 J1002 INV 33V J1003 J1004 J1005...

Page 50: ...10 18 Jack CBA Function CBA Junction CBA Top View Function CBA Junction CBA Jack CBA BA0C70F01021...

Page 51: ...10 19 Jack CBA Function CBA Junction CBA Bottom View BA0C70F01021 Function CBA Junction CBA Jack CBA...

Page 52: ...tic Diagram S VIDEO Y S VIDEO Y 0 2V 0 2V 20 20 s S VIDEO C S VIDEO C 0 2V 0 2V 20 20 s VIDEO Y VIDEO Y 0 2V 0 2V 20 20 s 20 20 s VIDEO Pr VIDEO Pr 0 2V 0 2V 20 20 s VIDEO Pb VIDEO Pb 0 2V 0 2V 20 20...

Page 53: ...Pin 26 of CN404 AUDIO L AUDIO L 0 5V 0 5V 0 5m 0 5ms WF7 Pin 22 of CN401 20 20 s VIDEO G VIDEO G 0 5V 0 5V 20 20 s VIDEO R VIDEO R 0 5V 0 5V 20 20 s Input PAL Color Bar Signal with 1kHz Audio Signal W...

Page 54: ...ON 5V AL 5 5V PROTECT3 PROTECT1 4 21 23 17 19 24 22 20 18 16 12 14 8 10 15 13 11 9 7 3 5 6 2 1 4 HEADPHONE L RGB AUDIO L OUT RGB AUDIO R OUT GND RGB AUDIO R IN RGB AUDIO L IN NU GND NU GND GND NU NU C...

Page 55: ...3 L3 B1 B18 B9 X3301 B9 L19 B7 L3 A17 A16 B23 L13 B12 L13 L13 L3 L3 B4 L1 L1 L1 L3 B14 A1 L8 L1 L1 A5 B8 L8 B8 A3 See Electrical Parts List for parts with this mark Digital Main CBA Unit AC601 Functio...

Page 56: ...13 2 A0C70_71PEX Packing S4 S5 S3 Tape Packing Tape Packing Tape Packing Tape S6 L17 X1 Some Ref Numbers are not in sequence Stand Assembly X3 X4 FRONT FRONT X2 1 X2 2 S1 S2 Tape...

Page 57: ...4F0 101 CL303 WIRE ASSEMBLY 29PIN FFC 29PIN 50MM WX1A94F0 101 CL401 WIRE ASSEMBLY 29PIN FFC 29PIN 50MM WX1A94F0 101 CL404 WIRE ASSEMBLY 29PIN FFC 29PIN 50MM WX1A94F0 101 CL801 WIRE ASSEMBLY 2PIN 2PIN...

Page 58: ...04 CAP CHIP 1608 Z Y5V 0 1 F 50V CHD104EYA036 C301 ELECTROLYTIC CAP 47 F 25V M or CE1EMASDL470 CAP ELE 47 F 25V M 85 or CED470KSN001 CAP ELE 47 F 25V M 85 CED470TEP001 C302 CHIP CERAMIC CAP 1608 B K 0...

Page 59: ...02 C614 ELECTROLYTIC CAP 3300 F 10V M or CE1AMZPDL332 Ref No Mark Description Part No ELECTROLYTIC CAP 3300 F 10V or CE1AMZNDL332 CAP ELE 3300 F 10V M 85 or CEB332KSN002 CAP ELE 3300 F 10V M 85 CEB332...

Page 60: ...P 1608 K X7R 0 1 F 50V CHD104EYA032 Ref No Mark Description Part No C1006 ELECTROLYTIC CAP 10 F 50V M or CE1JMASDL100 CAP ELE 10 F 50V M 85 or CEF100KSN001 CAP ELE 10 F 50V M 85 CEF100TEP001 C1007 CHI...

Page 61: ...JC1129JSH001 CN402 FFC CONNECTOR IMSA 9615S 29A PP A or JC96J29ER007 CONNECTOR PRINT MES 00 6232 029 006 800 or JC62G29UG026 Ref No Mark Description Part No CONNECTOR PRINT MES 29 S 1 0 11 29P JC1129J...

Page 62: ...431BZTR E1 NSZBA0TBCD01 Ref No Mark Description Part No D635 SWITCHING DIODE 1SS133 T 77 or QDTZ001SS133 DIODE SWITCHING HSS4148TE E or QDTZ0HSS4148 DIODE SWITCHING 1N4148 F0021 NDTZ01N4148F D636 DIOD...

Page 63: ...art No DIODE SWITCHING 1N4148 F0021 NDTZ01N4148F D1562 SWITCHING DIODE 1SS133 T 77 or QDTZ001SS133 DIODE SWITCHING HSS4148TE E or QDTZ0HSS4148 DIODE SWITCHING 1N4148 F0021 NDTZ01N4148F D1563 SWITCHING...

Page 64: ...T or QQSY2SA1015F Ref No Mark Description Part No TRANSISTOR 2SA1015 GR TE2 F T or QQS12SA1015F PNP TRANSISTOR 2SA1980Y AT or NQSY02SA1980 PNP TRANSISTOR 2SA1980 G or NQSG02SA1980 PNP TRANSISTOR 2SA1...

Page 65: ...266 GR AT P or NQS4KTA1266P TRANSISTOR 2SA1015 Y TE2 F T or QQSY2SA1015F TRANSISTOR 2SA1015 GR TE2 F T or QQS12SA1015F PNP TRANSISTOR 2SA1980Y AT or NQSY02SA1980 Ref No Mark Description Part No PNP TR...

Page 66: ...43UFO or NQ102SC5343U NPN TRANSISTOR SMD 2SC5343UFY or NQ1Y2SC5343U NPN TRANSISTOR SMD 2SC5343UFG or NQ1G2SC5343U Ref No Mark Description Part No NPN TRANSISTOR SMD 2SC5343UFL NQ1L2SC5343U Q1023 NPN T...

Page 67: ...8 1 10W 0 or RRXAZR5Z0000 RES CHIP 1608 1 10W J 0 RRXA000YF002 R311 WIRE CP STP S 0 50 or XZ40F0REN001 WIRE CP STP S 0 60 or XZ40F0REN002 Ref No Mark Description Part No WIRE CP 6113 05603 0220 or XZ4...

Page 68: ...34 RES CHIP 3216 1 4W J 680k RRX4684YF004 Ref No Mark Description Part No R610 RES CARBON FILM T 1 4W J 390 or RCX4391T1001 RES CARBON FILM 1 4W J 390 or RCX4391FS002 RES CARBON FILM 1 4W J 390 RCJ391...

Page 69: ...or RRXAJR5Z0103 RES CHIP 1608 1 10W J 10k RRXA103YF002 R675 RES CARBON FILM T 1 4W J 10 or RCX4100T1001 Ref No Mark Description Part No RES CARBON FILM 1 4W J 10 or RCX4100FS002 RES CARBON FILM 1 4W...

Page 70: ...2YF002 R1021 CHIP RES 1 10W J 1k or RRXAJR5Z0102 Ref No Mark Description Part No RES CHIP 1608 1 10W J 1 0k RRXA102YF002 R1023 CHIP RES 1 10W J 1k or RRXAJR5Z0102 RES CHIP 1608 1 10W J 1 0k RRXA102YF0...

Page 71: ...A222YF002 R1558 CHIP RES 1 10W J 24k or RRXAJR5Z0243 RES CHIP 1608 1 10W J 24k RRXA243YF002 R1559 CHIP RES 1 10W J 9 1k or RRXAJR5Z0912 Ref No Mark Description Part No RES CHIP 1608 1 10W J 9 1k RRXA9...

Page 72: ...NVQZVR10D471 VARISTOR Q TVR10471KS42Y NVQKTVR10471 T601 TRANS POWER BCK 35AO or LTT3PEMEK004 TRANS POWER BCK 35 0746 LTT3PE0XB061 TM601 EYELET TYPE D 1 0VM406868 TM602 EYELET TYPE D 1 0VM406868 Ref N...

Page 73: ...M Y or NQSY2SA1980M PNP TRANSISTOR 2SA1980MG AT NQSG2SA1980M Ref No Description Part No RESISTORS R102 CHIP RES 1608 1 10W 0 or RRXAZR5Z0000 RES CHIP 1608 1 10W J 0 RRXA000YF002 R103 CHIP RES 1 10W J...

Page 74: ...20100507 15 17 A0C70 71EL CN102B 242SERIESCONNECTORTUC P06X B1WHT ST JCTUB06TG002 Ref No Description Part No TU1 TUNER UNIT DTOS40AML201A UTNPSG0SM002 Ref No Description Part No...

Page 75: ...LT850 M22 LT851 M22 A0C70EP A0C71EP 2010 06 03...

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