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 See also: Service Manual

SERVICE MANUAL

17" LCD Monitor
LM721A Srial
Date: Jul-02-03

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the LM721A and is the answer not in the manual?

Questions and answers

Subscribe to Our Youtube Channel

Related Manuals for AOC LM721A

Summary of Contents for AOC LM721A

  • Page 1: Service Manual

    SERVICE MANUAL 17” LCD Monitor LM721A Srial Date: Jul-02-03...

  • Page 2: Monitor Specifications

    Serial Service Manual Rev: A LM721A 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.) 25 ms Video Analog /Digital Input Sync.

  • Page 3: Lcd Monitor Description

    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. The Inverter board will drive the backlight of panel and the DC-DC conversion. The Adapter will provide the 12V DC-power to inverter/power board.

  • Page 4: General Instructions

    Serial Service Manual Rev: A LM721A 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 5: Osd Table

    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. Input Signal source sleeted (select Analog or Digital input Input Selected source).

  • Page 6: Input Signal Connector

    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 7: Vesa 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 640x480@72Hz 832 x 520 37.861 72.809 31.500 640x480@75Hz 840 x 500 37.500 75.00 31.500...
  • Page 8 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 ; 60 Hertz. Parameter must be reached within 3 seconds of turn-on.

  • Page 9: Specification

    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) -DE(Data Enable) mode -COMPACT SIZE DESIGN 4.4.2 Display Characteristics Items Specification...
  • Page 10 Serial Service Manual Rev: A LM721A 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 Output Current...

  • Page 12: Software Flow Chart

    2 Software Flow Chart...
  • Page 13 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. 7) Are the AUTO and SELECT keys pressed ? 8) Enter factory mode.
  • Page 14 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) (CN403) (U204) (CN102) DB15_SDA, DB15_SCL EEPROM EEPROM (D-I only) 24C02 24C02 (U104)

  • Page 15: Inverter/Power Board

    2 Inverter/Power Board Inverter Block Diagram P a r a 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 D im m in g c o n tro l D r iv e r C irc u it ( P W M )
  • Page 16 Service Manual Rev: A LM721A Power Block Diagram Page Page Page Page 19 19 19 19 of of of of 59 59 59 59...
  • Page 17 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 DDCCLK SCL_IN SDA_IN DDCDAT SDA_IN VS_DVI A_VSYNC R102 R102¹qªý½Ð¾aªñ ANALOG PORT D-SUB RX1-IN AGND RX1- RX1+IN RX1+ SGND DVI_5V ZD101...
  • Page 18 Service Manual Rev: A LM721A FB201 FB202 +A3.3V +A3.3V FB208 +2.5V 3.3V_DDDS Close to respective power Pins C222 C224 C223 C225 +A3.3V 22uF/16V 22uF/16V C259 FB209 0.1uF/16V 0.1uF/16V C212 C211 +A3.3V 100uF/16V C213 C215 C216 C219 C220 C214 C217 C218 22uF/16V 0.1uF/16V...
  • Page 19 Service Manual Rev: A LM721A A3.3V AU17 LVDS INTERFACE 10/16 modify +3.3V A3.3V FB301 C300 C301 C302 C329 600OHM CHANGE B G R DATE SIGNAL 4/18 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 20 ON/OFF Vout 600(1206) +2.5V 33A8009-12G-H C106 C107 C112 470 uF/16V 470 uF/16V 0.1U/25V R107 AOC (Top Victory) Electronics Co., Ltd. is power GND Title R108 1.POWER Size Document Number IDPC7425A6(715L963-1-2) is signal GND Date: Friday, August 16, 2002 Sheet INVERTER SCHEMATICS...
  • Page 21 R223 12K 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 ID7425A6(715L963-1-2)
  • Page 22 +3.3V +A3.3V +A5V ON/OFF 3\8009-12G-H CON203 120K 12V or 14V 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 23: Key Board

    6.3 Key Board U106D +12V LED_ORANGE R420 C418 U106C 74LVC14 0.1uF/16V LED_GRN CN401 Q406 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) STDBY STDBY MUTE MUTE RP402...

  • Page 24: Main Board

    Main Board...
  • Page 25 Inverter/Power Board...

  • Page 26: Audio Board

    7.3 Keypad Board and Audio board 1. Keypad Board 2.Audio Board...

  • Page 27: Equipments And Tools Requirement

    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 28: Troubleshooting

    8.2 Trouble Shooting 8.2.1 Main Board 1.NO SCREEN APPEAR Measured CN402 pin 9/10 = 2.5 V? Measured CN402 pin 7/8= 3.3V? Check Correspondent component. Is there any shortage or cold solder? Measured CN402 pin 3/4= 5V? Measured CN402 pin 12= 12V? Yes.
  • Page 29 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 should =0 v, OK, R308 have NG, no Voltage Check U202 pin 1,2,3,4= 5V...
  • Page 30 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 31: Power/Inverter Board

    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 Check start voltage for the pin3 of IC901 Change IC901 Repeating the start voltage Check the auxiliary voltage is smaller than 20V...
  • Page 32 2.) W / LED , No Backlight Check Fuse F101 =12V To change 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. Check Q205/Q207/Q203/D201 Check the resonant wave of pin2 &...

  • Page 33: Keypad Board

    Service Manual Rev: A LM721A 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 34: White-Balance, Luminance Adjustment

    Service Manual Rev: A LM721A 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 35: Edit Content

    Service Manual Rev: A LM721A 10. EDIT Content A. D-SUB Connector (Analog) Note: Byte 0C, 0D, 0E, 0F means Serial No. Byte 10, 11 means Manufacture Time. Byte 7F means checksum B. DVI Connector (Digital) Note: Byte 0C, 0D, 0E, 0F means Serial No. Byte 10, 11 means Manufacture Time. Byte 7F means checksum...

  • Page 36: Bom List

    Service Manual Rev: A LM721A 11. BOM List ADPC12416AE LCD ADAPTER ASS'Y AUDIO BOARD FOR AUPC782A3 T780K* CBPC782KADA CONVERSION BOARD IDPC7425A1 LCD INVERTER BOARD KEY BOARD FOR KEPC780KA9 T780K*SNI WOODEN PALLET 0.0067 WOODEN PALLET 0.0067 12L 394 2 A RUBBER FOOT...
  • Page 37 Service Manual Rev: A LM721A 瞀 à 狾 44L9003210 0.054 45L 76 28 RN pe bag for base/MANUAL 45L 77500 BARCODE RIBBON 45L 77501 BARCODE RIBBON 45L 77511 45L 88500 1 PE BAG 0.0067 45L 88500 2 PE BAG 0.0067...
  • Page 38 Service Manual Rev: A LM721A ADPC12416AB6 LCD ADAPTER A6 ASS'Y 2 GND1 9L6002 1 40L 581700 6A LABEL 1.05 6 4500 1213600 簧 盿 2 IC903 56L 139 3B PC123 Y82 2 R911 61L152M10457F MOFR 100KOHM +-5% 2W 2 C901 63L 107334 5 0.33UF 275VAC...
  • Page 39 Service Manual Rev: A LM721A 705L 560 61 04 NR901 ASS'Y 715L 901 1 4 ADAPTOR 705L 560 57 03 Q901 ASS'Y 705L 560 61 03 R930 ASS'Y 705L 780 93 03 D911 ASS'Y 3 L901 6L 31502 1.5MM RIVET...
  • Page 40 Service Manual Rev: A LM721A 3 R916 61L0805472 CHIRP 4.7K OHM +-5% 1/1 3 R917 61L0805472 CHIRP 4.7K OHM +-5% 1/1 3 R918 61L0805472 CHIRP 4.7K OHM +-5% 1/1 3 R920 61L0805623 CHIPR 62K OHM +-5% 1/10 3 R921 61L0805683...
  • Page 41 Service Manual Rev: A LM721A 3 D904 93L 6432V LL4148-GS08 3 D905 93L 6432V LL4148-GS08 3 ZD901 93L 39S500 T 19VZENER PIODE 33L6007 1 LENS HI-POT GND LABEL FOR 40L 154501 1 40L416B615 1A ADAPTER ID LABEL 1.02 45L 88525 E...

  • Page 42: Main Board

    Service Manual Rev: A LM721A 90L6059 1 床荐 715L 964 2 AUDIO BOARD 60*45 3 J1 95L 90 23 TIN COATED 3 J2 95L 90 23 TIN COATED 3 J3 95L 90 23 TIN COATED 3 J4 95L 90 23...
  • Page 43 Service Manual Rev: A LM721A ň 聁瞜奎 55L 100600 A 55L 100603 瞜奎 2 U202 56L1133 41 A1 W39F010U 2 U202 56L1133 42 A1 A290011T-70 LOW ESR 150UF 25V 2 C401 67L215C151 4H 8*7MM LOW ESR 150UF 25V 2 C404...
  • Page 44 Service Manual Rev: A LM721A 3 R227 61L0603000 CHIPR 0OHM +-5% 1/16W 3 R235 61L0603000 CHIPR 0OHM +-5% 1/16W 3 R305 61L0603000 CHIPR 0OHM +-5% 1/16W 3 R307 61L0603000 CHIPR 0OHM +-5% 1/16W 3 R313 61L0603000 CHIPR 0OHM +-5% 1/16W...
  • Page 45 Service Manual Rev: A LM721A 3 R123 61L0603153 CHIPR 15KOHM+-5% 1/16W 3 R124 61L0603153 CHIPR 15KOHM+-5% 1/16W 3 R131 61L0603222 CHIPR 2.2K OHM+-5% 1/16 3 R132 61L0603222 CHIPR 2.2K OHM+-5% 1/16 3 R204 61L0603272 CHIP 2.7K OHM 1/16W 3 R308...
  • Page 46 Service Manual Rev: A LM721A 3 C109 65L0603104 12 0.1UF +-10% 16V X7R 3 C113 65L0603104 12 0.1UF +-10% 16V X7R 3 C201 65L0603104 12 0.1UF +-10% 16V X7R 3 C202 65L0603104 12 0.1UF +-10% 16V X7R 3 C203 65L0603104 12 0.1UF +-10% 16V X7R...
  • Page 47 Service Manual Rev: A LM721A 3 C249 65L0603104 12 0.1UF +-10% 16V X7R 3 C300 65L0603104 12 0.1UF +-10% 16V X7R 3 C301 65L0603104 12 0.1UF +-10% 16V X7R 3 C302 65L0603104 12 0.1UF +-10% 16V X7R 3 C305 65L0603104 12 0.1UF +-10% 16V X7R...
  • Page 48 Service Manual Rev: A LM721A 3 C258 67L 312101 3 SMD 100UF +-20% 16V 3 C259 67L 312101 3 SMD 100UF +-20% 16V 3 C324 67L 312101 3 SMD 100UF +-20% 16V 3 C325 67L 312101 3 SMD 100UF +-20% 16V...
  • Page 49 Service Manual Rev: A LM721A POWER MLL5232B BY FULL 3 ZD106 93L 39149 POWER MLL5232B BY FULL 3 ZD107 93L 39149 POWER MLL5232B BY FULL 3 ZD108 93L 39149 POWER MLL5232B BY FULL 3 ZD109 93L 39149 POWER 3 D106...
  • Page 50 Service Manual Rev: A LM721A LOW ESR 150UF 25V 2 C223 67L215C151 4H 8*7MM 2 L101 71L 55 28 FERRITE BEAD 7.62*5.08* 2 L102 73L 253138 L CHOKE BY LI TAI 2 L201 73L 253138 L CHOKE BY LI TAI...
  • Page 51 Service Manual Rev: A LM721A 3 Q211 57L 761 2 2SC5706-TL-SMT 3 Q212 57L 761 2 2SC5706-TL-SMT 3 Q209 57L 761 3 2SC5824R SMT 3 Q210 57L 761 3 2SC5824R SMT 3 Q211 57L 761 3 2SC5824R SMT 3 Q212...
  • Page 52 Service Manual Rev: A LM721A 3 R237 61L0603561 CHIP 560 OHM 1/16W 3 R234 61L0603681 CHIP 680 OHM 1/16W 3 R235 61L0603681 CHIP 680 OHM 1/16W 3 R232 61L1206102 CHIP 1K OHM 5% 1/8W 3 R233 61L1206102 CHIP 1K OHM 5% 1/8W...
  • Page 53 Service Manual Rev: A LM721A ADAPTOR BY YAO SHENG 3 PT202 80LL17T 3 YS 3 F101 84L 52 5 CHIP FUSE 6.5A GET-HAND 3 D207 93L 6432U MLL4148 SMD 3 D208 93L 6432U MLL4148 SMD 3 D207 93L 6432V LL4148-GS08...
  • Page 54 Service Manual Rev: A LM721A 2 SW103 77L 600 1GHJ KEY SWITCH 2 SW104 77L 600 1GHJ KEY SWITCH 2 SW105 77L 600 1GHJ KEY SWITCH 2 DP101 81L 12 1 GP 715L 982 1 S KEY BOARD 3 J001...

Table of Contents