AOC LM721A Service Manual
  1. Manuals
  2. Brands
  3. AOC Manuals
  4. Monitor
  5. LM721A
  6. Service manual
AOC LM721A Service Manual

AOC LM721A Service Manual

17” lcd monitor
Hide thumbs Also See for LM721A:
Table of Contents

Advertisement

Quick Links

Download this manual
LM721A Service Manual
Rev: A

SERVICE MANUAL

17" LCD Monitor
LM721A
THESE DOCUMENTS ARE FOR REPAIR SERVICE INFORMATION ONLY. EVERY REASONABLE
EFFORT HAS BEEN MADE TO ENSURE THE ACCURACY OF THIS MANUAL; WE CANNOT GUARANTEE
THE ACCURACY OF THIS INFORMATION AFTER THE DATE OF PUBLICATION AND DISCLAIMS RE
LIABILITY FOR CHANGES, ERRORS OR OMISSIONS.
Prepared: LiuYongFeng
Date: May-16-04
Page 1 of 56

Advertisement

Table of Contents
loading

Related Manuals for AOC LM721A

Summary of Contents for AOC LM721A

  • Page 1: Service Manual

    LM721A Service Manual Rev: A SERVICE MANUAL 17” LCD Monitor LM721A THESE DOCUMENTS ARE FOR REPAIR SERVICE INFORMATION ONLY. EVERY REASONABLE EFFORT HAS BEEN MADE TO ENSURE THE ACCURACY OF THIS MANUAL; WE CANNOT GUARANTEE THE ACCURACY OF THIS INFORMATION AFTER THE DATE OF PUBLICATION AND DISCLAIMS RE LIABILITY FOR CHANGES, ERRORS OR OMISSIONS.

  • Page 2: Revision History

    LM721A Service Manual Rev: A Revision History Revision Date Page Items Modification May-16-04 First version release; Page 2 of 56...

  • Page 3: Table Of Contents

    LM721A Service Manual Rev: A TABLE OF CONTENTS TABLE OF CONTENTS---------------------------------------------------------------------------------------------------3 1.MONITOR SPECIFICATIONS---------------------------------------------------------------------------------5 2. LCD MONITOR DESCRIPTION -------------------------------------------------------------------------------6 3. OPERATING INSTRUCTIONS -------------------------------------------------------------------------------7 3.1 GENERAL INSTRUCTIONS ---------------------------------------------------------------------------------------7 3. CONTROL BUTTONS -------------------------------------------------------------------------------------------7 3.3 ADJUSTING THE PICTURE-------------------------------------------------------------------------------------7 4. INPUT/OUTPUT SPECIFICATION-----------------------------------------------------------------------------9 4.1 INPUT SIGNAL CONNECTOR ------------------------------------------------------------------------------9 4.2 FACTORY PRESET DISPLAY MODES...
  • Page 4 LM721A Service Manual Rev: A 7.3 KEYPAD BOARD AND AUDIO BOARD---------------------------------------------------------------------31 8. MAINTAINABILITY --------------------------------------------------------------------------------------------------32 8.1 EQUIPMENTS AND TOOLS REQUIREMENTS ----------------------------------------------------32 8.2 TROUBLE SHOOTING -----------------------------------------------------------------------------------33 9. WHITE-BALANCE, LUMINANCE ADJUSTMENT -------------------------------------------------39 10. BOM LIST --------------------------------------------------------------------------------------------------------40 Page 4 of 56...

  • Page 5: Monitor Specifications

    LM721A Service Manual Rev: A 1. Monitor Specifications Driving system TFT Color LCD LCD Panel Size 43.2cm(17.0") Pixel pitch 0.264mm( H )x 0.264mm( V ) Viewable angle 150˚ (H) 110˚ (V) Response time (typ.) 16 ms Video Analog /Digital Input Sync.

  • Page 6: Lcd Monitor Description

    LM721A Service Manual Rev: A 2. Lcd Monitor Description The LCD MONITOR will contain a main board, an inverter/power board, keypad board , Audio board and external power adapter which house the flat panel control logic, brightness control logic and DDC.

  • Page 7: Operating Instructions

    LM721A Service Manual Rev: A 3. Operating Instructions 3.1 General Instructions Press the power button to turn the monitor on or off. The other control buttons are located at front panel of the monitor. By changing these settings, the picture can be adjusted to your personal preferences.
  • Page 8 LM721A Service Manual Rev: A OSD Table: Contrast Adjust the picture contrast. Brightness Adjust the picture brightness. Focus Adjust picture Focus. Clock Adjust picture Clock. H_Position Adjust the horizontal position of the picture. V.Position Adjust the vertical position of the picture.

  • Page 9: Input/Output Specification

    LM721A Service Manual Rev: A 4. Input/Output Specification 4.1 Input Signal Connector PIN NO. DESCRIPTION DESCRIPTION PI N NO. Green Detect Cable Blue Ground DDC-Serial Data Ground H-Sync R-Ground V-Sync G-Ground DDC-Serial Clock B-Ground VGA connector layout Page 9 of 56...

  • Page 10: Factory Preset Display Modes

    LM721A Service Manual Rev: A 4.2 Factory Preset Display Modes VESA MODES Horizontal Vertical Nominal Sync Nominal Sync Nominal Pixel Mode Resolution Total Frequency Polarity Freq. Polarity Clock +/- 0.5kHz +/- 1 Hz (MHz) 640x480@60Hz 800 x 525 31.469 59.940 25.175...

  • Page 11: Power Supply Requirements

    LM721A Service Manual Rev: A 4.3 Power Supply Requirements 4.3.1 Input Requirements PARAMETER RANGE CONDITION Input AC Voltage 100 to 240VAC RMS Universal input full range Input Frequency 60Hz @ 100VAC to 50Hz @ 240VAC Input Current Less than 2.0 Amps RMS Input voltage 100 VAC RMS ;...

  • Page 12: Panel Specification (Qdi El07)

    LM721A Service Manual Rev: A 4.4 PANEL SPECIFICATION (Hydis-200) 4.4.1 Panel Feature -High contrast ratio, high aperture structure -TN(Twisted Nematic) mode -Wide viewing angle -High speed response -SXGA(1280 x 1024 pixels) resolution -Low power consumption -2 dual CCFTs(Cold Cathode Fluorescent Tube)
  • Page 13 LM721A Service Manual Rev: A 4.4.4 Parameter guide line for CCFL Inverter INVERTER MAX BRINGTHNESS (Vadj:5.0v), LOAD=120KΩX4(ROOM TEMPERATURE 25 ±4 ℃ ℃) ITEM SYMBOL MIN. TYP. MAX. UNIT REMARK Input voltage 10.8 13.2 Input current 2250 2500 FOR 4 LOAD...

  • Page 14: Block Diagram

    LM721A Service Manual Rev: A 5. Block Diagram 5.1 Monitor Exploded View Page 14 of 56...

  • Page 15: Software Flow Chart

    LM721A Service Manual Rev: A 5.2 Software Flow Chart Page 15 of 56...
  • Page 16 LM721A Service Manual Rev: A Remark: 1) MCU initialize. 2) Is the EEprom blank ? 3) Program the EEprom by default values. 4) Get the PWM value of brightness from EEprom. 5) Is the power key pressed ? 6) Clear all global flags.

  • Page 17: Electrical Block Diagram

    LM721A Service Manual Rev: A 5.3 Electrical Block Diagram 5.3.1 Main Board Interface (CN301) LVDS THC63LVDM83R (U301/U302) Scalar gm5120/gm2120 Flash Memory (Include MCU,ADC,OSD) W39f010P-70B (U202) (U203) Hsync, EPR_SDA Vsync EPR_SCL DVI-I only Control EEPROM D-Sub Connector Interface 24C16 Connector (CN101)
  • Page 18 LM721A Service Manual Rev: A 5.3.2 Inverter/Power Board Inverter Block Diagram P a ra lle t-re s o n a n t V in B u c k C o n n e c to r in v e rte r...
  • Page 19 LM721A Service Manual Rev: A Power Block Diagram Page 19 of 56...

  • Page 20: Schematic

    LM721A Service Manual Rev: A 6. Schematic 6.1 Main Board 10/16 modify CN101 RX2-IN A_GND RX2- RX2+IN RX2+ SGND ED102 Connect two grounds at one single point only. ED101 SCL_IN SCL_IN DDCCLK SDA_IN SDA_IN DDCDAT VS_DVI A_VSYNC 筿　叫綼　 R102 R102...
  • Page 21 LM721A Service Manual Rev: A FB201 FB202 +A3.3V +A3.3V FB208 +2.5V 3.3V_DDDS Close to respective power Pins C222 C224 C225 C223 +A3.3V 22uF/16V 22uF/16V C259 FB209 0.1uF/16V 0.1uF/16V C212 100uF/16V C211 +A3.3V C213 C214 C215 C216 C219 C220 C217 C218 22uF/16V 0.1uF/16V...
  • Page 22 LM721A Service Manual Rev: A AU17 LVDS INTERFACE A3.3V 10/16 modify +3.3V A3.3V FB301 CHANGE B G R DATE SIGNAL 4/18 C300 C301 C302 C329 600OHM 0.1uF/16V 0.1uF/16V 0.1uF/16V 100uF/16V 4/29 ADD S/W TEST PBIAS CONTROLL R309 C330 0.01uF/16V PBIAS U301 NC(4.7K)

  • Page 23: Inverter/Power Board

    L105 ON/OFF Vout 600(1206) +2.5V 33A8009-12G-H C106 C107 C112 470 uF/16V 470 uF/16V 0.1U/25V AOC (Top Victory) Electronics Co., Ltd. is power GND R107 Title 1.POWER R108 Size Document Number IDPC7425A6(715L963-1-2) is signal GND Date: Friday, August 16, 2002 Sheet...
  • Page 24 R211 R219 Q212 1U/25V BAV99 C206 2SD2098 0.1U/25V R235 680 D208 R241 RLS4148 AOC (Top Victory) Electronics Co., Ltd. C222 C220 is power GND R239 R237 560 Title 0.47U/25V 1U/25V 2. FOR SAMSUNG LTM170EU-L01 INVERTER Size Document Number is signal GND...
  • Page 25 3\8009-12G-H CON203 12V or 14V 120K DC POWER SUPPLY SM02(8.0)B-BHS-1-TB CON204 120K MMST3904 5.6B SM02(8.0)B-BHS-1-TB AOC (Top Victory) Electronics Co., Ltd. 0V~5V Title CONVERTER&INVERTER FUNCTION CIRCUIT Size Document Number IDPC7425A6(715A963-1-2) Date: Saturday, July 13, 2002 Sheet Page 25 of 56...

  • Page 26: Key Board

    LM721A Service Manual Rev: A 6.3 Key Board U106D +12V LED_ORANGE R420 C418 U106C 74LVC14 0.1uF/16V LED_GRN Q406 CN401 Q405 R419 R418 MUTE STDBY SP(L) SP(R) C423 150pF 74LVC14 Earphone(L) Earphone(R) OUT(L) OUT(R) FB403 FB404 +A3.3V R402 R401 5/10 change A+3.3V CON12A(PITCH 2.0)

  • Page 27: Pcb Layout

    LM721A Service Manual Rev: A 7. PCB Layout 7.1 Main Board Page 27 of 56...
  • Page 28 LM721A Service Manual Rev: A Page 28 of 56...

  • Page 29: Inverter/Power Board

    LM721A Service Manual Rev: A 7.2 Inverter/Power Board Page 29 of 56...
  • Page 30 LM721A Service Manual Rev: A Page 30 of 56...

  • Page 31: Keypad Board And Audio Board

    LM721A Service Manual Rev: A 7.3 Keypad Board and Audio board 1. Keypad Board 2. Audio Board Page 31 of 56...

  • Page 32: Maintainability

    LM721A Service Manual Rev: A 8. Maintainability 8.1 Equipments and Tools Requirement 1.) Voltmeter. 2.) Oscilloscope. 1.) Pattern Generator. 2.) DDC Tool with a IBM Compatible Computer. 3.) Alignment Tool. 4.) LCD Color Analyzer. 5.) Service Manual. 6.) User Manual.

  • Page 33: Trouble Shooting

    LM721A Service Manual Rev: A 8.2 Trouble Shooting 8.2.1 Main Board 1. NO SCREEN APPEAR Measured CN402 pin 9/10 = 2.5 V? Check Correspondent component. Measured CN402 pin 7/8= 3.3V? Measured CN402 pin 3/4= 5V? Is there any shortage or cold solder? Measured CN402 pin 12= 12V? Yes.
  • Page 34 LM721A Service Manual Rev: A 2.PANEL-POWER CIRCUIT Check the PPWR panel power relative circuit, check R302 should have response from 0V to 5V Q301, Q302(pin 5,6,7,8) When we switch the power switch from on to off In normal operation, when LED =green, R302...
  • Page 35 LM721A Service Manual Rev: A 4.U203-DATA OUTPUT NG , no transition Measured DCLK(R240) DVS, DHS (pin 117,116 from U203 ) Is the waveform ok? DCLK around 48 MHZ , DVS=60.09Hz , DHS around 80 KHz ?(refer to input Replace GM5120 /2120 (U203) or signal=640x480@60 Hz 31k, and LED is replace MAINBOARD.
  • Page 36 LM721A Service Manual Rev: A 8.2.2 Power/Inverter Board 1.) No power Check to CN102 Pin1 and pin2 = 5V Check Interface board Check AC line volt 120V or 220V Change F901 , check BD901,Q903,IC901 Check the voltage of C905(+) Check bridge rectified circuit...
  • Page 37 LM721A Service Manual Rev: A 2.) W / LED , No Backlight Check Fuse F101 =12V To change F101=6.5A/63V Check ON/OFF signal Check Interface board Check U201 pin9=12V Change Q201 or Q202 Check the pin1 of U201 have correct wave Change U201 Check D201(-),D202(-) have the output of square wave at short time.

  • Page 38: Keypad Board

    LM721A Service Manual Rev: A 8.2.3 KeyPad Board OSD is unstable or not working Connect KeyPad Board Is KeyPad Board connecting normally ? Replace Button Switch Is Button Switch normally ? Replace KeyPad Board Is KeyPad Board Normally ? Check Main Board...

  • Page 39: White-Balance, Luminance Adjustment

    LM721A Service Manual Rev: A 9. White-Balance, Luminance adjustment Approximately 30 minutes should be allowed for warm up before proceeding white balance adjustment. Before started adjust white balance ,please setting the Chroma-7120 MEM. channel 1 to 6500 color, MEM. channel 2 to 7800 color, ( our 6500 parameter is x = 313 ±10, y = 329 ±10, Y = 200 ±10 cd/m...

  • Page 40: Bom List

    LM721A Service Manual Rev: A 10. BOM List Location Part No. Description Quantity Unit ADPC12416AE LCD ADAPTER ASS'Y AUPC782A3 AUDIO BOARD FOR T780K* CBPC782KADA CONVERSION BOARD IDPC7425A1 LCD INVERTER BOARD KEPC780KA9 KEY BOARD FOR T780K*SNI WOODEN PALLET 0.0067 WOODEN PALLET 0.0067...
  • Page 41 LM721A Service Manual Rev: A 45L 88500 1 PE BAG 0.0067 45L 88500 2 PE BAG 0.0067 45L 88606 PE BAG FOR BASE 45L 88607 PE BAG FOR MONITOR 45L 88609 B EPE COVER 50L 600 2 HANDLE1 50L 600 3...
  • Page 42 LM721A Service Manual Rev: A C902 65L305M1022EM 1000PF +-20% 250VAC/400 C903 65L305M1022EM 1000PF +-20% 250VAC/400 C916 65L306M3322F2 3300PF +-20% 400VAC Y1 C900 65L306M4722B2 4700PF +-20% 400VAC Y1 C921 67L 215102 3H 1000UF +-20% 16V C922 67L 215102 3H 1000UF +-20% 16V...
  • Page 43 LM721A Service Manual Rev: A IC902 56L 158 2 T 3PIN IC TL431C/T.I. IC905 56L 158 2 T 3PIN IC TL431C/T.I. IC902 56L 158 4 T HTL431 IC905 56L 158 4 T HTL431 C905 65L 1K152 1T6052 1.5NF/1KV Z5F+-10% C905 65L 1K152 1T6285 1.5NF/1KV Z5F+-10%...
  • Page 44 LM721A Service Manual Rev: A R903 61L1206684 CHIPR 680K OHM+-5% 1/8W R904 61L1206684 CHIPR 680K OHM+-5% 1/8W R905 61L1207304 CHIPR 300KOHM +-5% 1/4W R906 61L1207304 CHIPR 300KOHM +-5% 1/4W R907 61L1207304 CHIPR 300KOHM +-5% 1/4W R908 61L1207304 CHIPR 300KOHM +-5% 1/4W...
  • Page 45 LM721A Service Manual Rev: A R930 61L 2J47859B WIRE WOUND 0.47 OHM ZW 96L 29 6 SHRINK TUBE UL/CSA PARENT NO : 705L 780 93 03 911 ASS'Y 舱　 家舱 90L 396502 D HEAT SINK D911 93L 60226 STPS20H100CT D912...
  • Page 46 LM721A Service Manual Rev: A CN301 33L801724A H PIN HEADER 24P 2.0mm CN401 33L8022 12 H PIN HEADER FEMALE 2*6 9 CN402 33L8022 12 H PIN HEADER FEMALE 2*6 9 CN403 33L8027 14 WAFER 14P 2.0MM DIP DUA 40L 457624 1B...
  • Page 47 LM721A Service Manual Rev: A R305 61L0603000 CHIPR 0OHM +-5% 1/16W R307 61L0603000 CHIPR 0OHM +-5% 1/16W R313 61L0603000 CHIPR 0OHM +-5% 1/16W R315 61L0603000 CHIPR 0OHM +-5% 1/16W R318 61L0603000 CHIPR 0OHM +-5% 1/16W R319 61L0603000 CHIPR 0OHM +-5% 1/16W...
  • Page 48 LM721A Service Manual Rev: A R124 61L0603153 CHIPR 15KOHM+-5% 1/16W R131 61L0603222 CHIPR 2.2K OHM+-5% 1/16 R132 61L0603222 CHIPR 2.2K OHM+-5% 1/16 R204 61L0603272 CHIP 2.7K OHM 1/16W R308 61L0603302 CHIPR 3K OHM +-5% 1/16W R125 61L0603470 CHIPR 47 OHM +-5% 1/16W...
  • Page 49 LM721A Service Manual Rev: A C109 65L0603104 12 0.1UF +-10% 16V X7R C113 65L0603104 12 0.1UF +-10% 16V X7R C201 65L0603104 12 0.1UF +-10% 16V X7R C202 65L0603104 12 0.1UF +-10% 16V X7R C203 65L0603104 12 0.1UF +-10% 16V X7R...
  • Page 50 LM721A Service Manual Rev: A C248 65L0603104 12 0.1UF +-10% 16V X7R C249 65L0603104 12 0.1UF +-10% 16V X7R C300 65L0603104 12 0.1UF +-10% 16V X7R C301 65L0603104 12 0.1UF +-10% 16V X7R C302 65L0603104 12 0.1UF +-10% 16V X7R...
  • Page 51 LM721A Service Manual Rev: A C256 67L 312101 3 SMD 100UF +-20% 16V C257 67L 312101 3 SMD 100UF +-20% 16V C258 67L 312101 3 SMD 100UF +-20% 16V C259 67L 312101 3 SMD 100UF +-20% 16V C324 67L 312101 3...
  • Page 52 LM721A Service Manual Rev: A ZD105 93L 39149 MLL5232B BY FULL POWER ZD106 93L 39149 MLL5232B BY FULL POWER ZD107 93L 39149 MLL5232B BY FULL POWER ZD108 93L 39149 MLL5232B BY FULL POWER ZD109 93L 39149 MLL5232B BY FULL POWER...
  • Page 53 LM721A Service Manual Rev: A 2 L201 73L 253138 Y CHOKE 2 L202 73L 253138 Y CHOKE CN101 88L 304 1S DC POWER JACK CN101 88L 3041CE DC JACK CON201 33L8020 3 J WAFER CON202 33L8020 3 J WAFER CON201...
  • Page 54 LM721A Service Manual Rev: A R202 61L0603103 CHIPR 10K OHM +-5% 1/16 R203 61L0603103 CHIPR 10K OHM +-5% 1/16 R204 61L0603103 CHIPR 10K OHM +-5% 1/16 R238 61L0603123 CHIP 12K OHM 1/16W R239 61L0603123 CHIP 12K OHM 1/16W R107 61L0603151...
  • Page 55 LM721A Service Manual Rev: A R228 61L1206202 CHIP 2K 5% 1/8W R229 61L1206202 CHIP 2K 5% 1/8W R230 61L1206202 CHIP 2K 5% 1/8W R231 61L1206202 CHIP 2K 5% 1/8W C108 65L0805104 22 0.1UF +-10% 25V X7R 080 C109 65L0805104 22 0.1UF +-10% 25V X7R 080...
  • Page 56 LM721A Service Manual Rev: A D206 93L 6433P BAV99-SMT D203 93L 39S 1 T TZMC11-GS08 D204 93L 39S 1 T TZMC11-GS08 D203 93L 39S 3 T BZT52-C11 D204 93L 39S 3 T BZT52-C11 D203 93L 39S 8 T ZD RLZ11B ROHM...

Table of Contents