AOC LM927U Service Manual
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AOC LM927U Service Manual

AOC LM927U Service Manual

19” lcd monitor
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AOC LM927U

SERVICE MANUAL

19" LCD Monitor
LM927U
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 RELIABILITY
FOR CHANGES, ERRORS OR OMISSIONS.
1

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  • Page 1: Service Manual

    AOC LM927U SERVICE MANUAL 19” LCD Monitor LM927U 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 RELIABILITY...

  • Page 2: Table Of Contents

    AOC LM927U Table of Content Revision List……………………………………………………………………………………………………. 1. Monitor Specifications…………………………………………………………………………………….. 2. LCD Monitor Description………………………………………………………………………………….. 3. Operating Instructions…………………………………………………………………………………….. 3.1 General Instructions……………………………………………………………………………………... 3.2 Control Buttons…………………………………………………………………………………………... 3.3 Adjusting the Picture……………………………………………………………………………………….. 4. Input/Output Specification………………………………………………………………………………... 4.1 Input Signal Connector………………………………………………………………………………….. 4.2 Factory Preset Display Modes………………………………………………………………………….. 4.3 Power Supply Requirements………………………………………………………………………………...

  • Page 3: Revision List

    AOC LM927U Revision List Revision Date Change Description Jul-11-05 Original Revision...

  • Page 4: Monitor Specifications

    AOC LM927U MONITOR SPECIFICATIONS Driving system TFT Color LCD Size 48.0cm(19.0") Pixel pitch 0.294mm( H )x 0.294mm( V ) LCD Panel Viewable angle 170˚ (H) 170˚ (V) Response time (type) 25 ms for AU panel Sync. Type H/V TTL Input H-Frequency 30kHz –...

  • Page 5: Lcd Monitor Description

    AOC LM927U 2. LCD MONITOR DESCRIPTION The LCD MONITOR will contain a main board, a power board, a keypad board and an audio board which house the flat panel control logic, brightness control logic and DDC. The power board will provide AC to DC Inverter voltage to drive the backlight of panel and the main board chips each voltage.

  • Page 6: Operating Instructions

    AOC LM927U 3. OPERATING INSTRUCTIONS 3.1 GENERAL INSTRUCTIONS Press the power button to turn the monitor on or off. The control buttons are located in the side of the panel of the monitor. By changing these settings, the picture can be adjusted to your personal preferences.

  • Page 7: Adjusting The Picture

    AOC LM927U 3.3 ADJUSTING THE PICTURE Adjustment steps: 1. Press the MENU-button to activate the OSD window. 2. Press < or > to select the desired function. 3. Press the MENU-button to select the function that you want to adjust.
  • Page 8 AOC LM927U Auto Adjust the H/V Position, Auto Config Focus and Clock of picture. (Analog-Only Do not execute Auto Config, Model) return to main menu. Adjust the horizontal position of H. Position the OSD. OSD Setup Adjust the vertical position of the V.

  • Page 9: Input/Output Specification

    AOC LM927U 4. Input/Output Specification 4.1 Input Signal Connector PIN NO. DESCRIPTION PI N NO. DESCRIPTION Red Video No Pin! Green Video Logic Ground Blue Video Monitor Ground Monitor Ground DDC-Serial Data DDC-Return H-Sync Red Ground V-Sync Green Ground DDC-Serial Clock...

  • Page 10: Factory Preset Display Modes

    AOC LM927U 4.2 Factory Preset Display Modes： VESA MODES Horizontal Vertical Nominal Sync Nominal Sync Nominal Frequency Polarity Freq. Polarity Pixel Mode Resolution Total +/- 0.5kHz +/- 1 Hz Clock (MHz) 640x480@60Hz 800 x 525 31.469 59.940 25.175 640x480@72Hz 832 x 520 37.861...

  • Page 11: Power Supply Requirements

    AOC LM927U 4.3 Power Supply Requirements A/C Line voltage range 100 V ~ 240 V 50 ± 3Hz, 60 ± 3Hz A/C Line frequency range Current 1.5A max at 100V; 0.8A max at 240 V Peak surge current < 55A peak at 240 VAC and cold starting Leakage current <...

  • Page 12: Optical Characteristics

    AOC LM927U 4.4.3 Optical Characteristics 4.4.4 Parameter guide line for CCFL Inverter  ...

  • Page 13: Block Diagram

    AOC LM927U 5. Block Diagram 5.1 Monitor Exploded View BEZEL 34G1239 MAIN FRAME PANEL REAR COVER 15G5960 SHIELD 85G651-3 34G1240 HINGE ASSY COVER VESA 37G 478-1 W33G4673 33G4642 BUTTON FUNC KEY BOARD SPK BOX COVER -R 34G1242 COVER TILT 33G4647...

  • Page 14: Software Flow Chart

    AOC LM927U 5.2 Software Flow Chart...
  • Page 15 AOC LM927U 1) MCU initialize. 2) Is the EPROM blank? 3) Program the EPROM by default values. 4) Get the PWM value of brightness from EPROM. 5) Is the power key pressed? 6) Clear all global flags. 7) Are the AUTO and SELECT keys pressed? 8) Enter factory mode.

  • Page 16: Electrical Block Diagram

    AOC LM927U 5.3 Electrical Block Diagram 5.3.1 Main Board EEPROM LCD Interface 24C16 MST8131A PQFP-128 Crystal 14.318MHZ (Include: ADC, OSD etc) D-SUB OSD Control Connector Interface (Keypad) EEPROM 24C02...

  • Page 17: Inverter/Power Board

    AOC LM927U 5.3.2 Inverter/Power Board...

  • Page 19: Schematic

    AOC LM927U 6. Schematic 6.1 Main Board 715L1150-B MST8131A SCHEMATIC GNDR GNDR GNDG GNDG DDC_CLK VCC2.5 VCC3.3 VAA1 VAA2 VAA3 VAA4 DDC_DAT GNDB GNDB ST_DET1 HSYNC HSYNC ST_DET2 VSYNC VSYNC DDC_CLK DDC_DAT VCC2.5 VCC3.3 VAA1 VAA2 VAA3 CLK+ CLK+ VAA4...
  • Page 20 AOC LM927U VCC5V+ VCC5V SOT-223 D202 U201 VCC12V DIODE R202 VCC2.5 VCC12V RT9164-25CG CON402(PITCH 2.54) 　 1/16W VCC2.5 CN201 ON_OFF R201 4.7K 　 1/16W C210 C211 C212 VCC12V VCC5V VCC12V D201SCHOTTEYDIODE C201 R212 4.7K 　 1/16W 0.1uF 47uF/16V 0.1uF VCC5V...
  • Page 21 AOC LM927U CN301 DB15 FB301 1/16W R301 1/16W C304 0.047uF 　 　 FB302 　 1/16W R302 　 1/16W C305 0.047uF FB303 　 1/16W R303 　 1/16W C306 0.047uF R304 　 1/16W C307 0.001uF PC5V R325 C301 C302 C303 VGA_CON 　...
  • Page 22 AOC LM927U VCC3.3 FB401 VCC2.5 FB402 VCC3.3 VCC2.5 600 OHM 600 OHM C405 C414 10uF/16V 10uF/16V VPLL VDVI VDPLL C406 C407 C408 C409 C410 C411 C412 C413 C415 C416 C417 C418 0.1uF 0.1uF 0.1uF 0.1uF 0.1uF 0.1uF 0.1uF 0.1uF 0.1uF 0.1uF...
  • Page 23 AOC LM927U PA[0..9] PA[0..9] LVA3P LVA3M CN503 LVACKP LVACKM LVB0M RXO0- RXO0+ LVB0P LVA2P LVB1M RXO1- RXO1+ LVB1P LVA2M LVB2M RXO2- RXO2+ LVB2P LVBCKM RXOC- RXOC+ LVBCKP LVA1P RXO3- RXO3+ LVB3M LVB3P LVA1M LVA0M RXE0- RXE0+ LVA0P LVA1M RXE1- RXE1+...
  • Page 24 AOC LM927U VCPU VCPU RP601 RP602 R601 R602 C601 10Kx4 10Kx4 C602 22pF U601 Y601 POWER EA/VP P0.0 ENTER P0.1 C603 11.0592MHZ RIGHT XTAL1 P0.2 LEFT P0.3 10u/16V AUTO P0.4 LED_B XTAL2 P0.5 C604 22pF LED_O P0.6 LED_G RESET P0.7 P2.0...

  • Page 25: Power Board

    AOC LM927U 6.2 Power Board 715L1142-3AUE...
  • Page 26 AOC LM927U...
  • Page 27 AOC LM927U...

  • Page 28: Audio Board

    TI_TDA3003D2/TDA3002D2 3W/9W AUDIO CN101 PIN 5 GND, PIN6 CGND DGND C137-C140 0.1UF FOR EMI 0905 600 OHM 600 OHM Size Document Number /SHUTDOWN,PIN7 AOC 19"LCD MONITOR FOR LM929 VOLUME,PIN8 MUTE 2003/07/18　э CN104 PIN2 ㎝CN103 PIN2虫縒钡　　癬,ぃ　ヴ　GND 钡 Date: Tuesday, October 28, 2003 Sheet...

  • Page 29: Pcb Layout

    AOC LM927U 7. PCB Layout 7.1 Main Board 715L1150-B...

  • Page 30: Power Board

    AOC LM927U 7.2 Power Board 715L1142–3-AUE...

  • Page 31: Audio Board

    AOC LM927U 7.3 Audio Board 715L1178-1 7.4 Key Board 715L1170 -1 7.5 USB Board 715L1157-1 7.6 CNPC Board 715L1131-1-17...

  • Page 32: Maintainability

    AOC LM927U 8. Maintainability 8.1 Equipments and Tools Requirement Voltmeter. Oscilloscope. Pattern Generator. DDC Tool with an IBM Compatible Computer. Alignment Tool. LCD Color Analyzer. Service Manual. User Manual.

  • Page 33: Trouble Shooting

    AOC LM927U 8.2 Trouble Shooting 8.2.1 Main Board No power No power Press power key and look if the picture is normal Please reinsert and make sure the AC of 100-240 is normal Reinsert or check the power section Measure U201 PIN2=2.5V U202 PIN2=3.3V...
  • Page 34 AOC LM927U No picture (LED orange) No picture The button if under control Check X601 oscillate waveform is Correspondent normal component. Measure U201 PIN2=2.5V U202 PIN2=3.3V Replace U601 Check Correspondent component X401 oscillate waveform is normal Check Correspondent component Replace U401...
  • Page 35 AOC LM927U White screen White screen Measure Q204 base is high level? Measure U201 PIN2=2.5V U202 PIN2=3.3V Check Check Q203 is broken or Correspondent CN503 solder? component X401 oscillate waveform Check is normal Correspondent component Check Correspondent component Replace PANEL...

  • Page 36: Power/Inverter Board

    AOC LM927U 8.2.2 Power/Inverter Board 1.) No power Check CN902 pin2, 4 = 12V Check AC line volt 110V or 220V Check AC input Check the voltage of C905(+) Check bridge rectified circuit and F901 circut Check start voltage for the pin3 of IC901...
  • Page 37 AOC LM927U 2.) No Backlight Check C201 (+) =12V Change F902 Check ON/OFF signal Check main board Check U201 pin9=12V Change Q201 or Q202 Check the pin1 of U201 have sawtooth wave Change U201 Check D201/D202 have the output of square ware at short time...

  • Page 38: Keypad Board

    AOC LM927U 8.2.3 Keypad Board OSD is unstable or not working Connect Key Pad Board Is Key Pad Board connecting normally? Is Button Switch normally? Replace Button Switch Is Key Pad Board normally? Replace Key Pad Board Check Main Board...

  • Page 39: White-Balance,Luminance Adjustment

    AOC LM927U 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 set the Chroma-7120 MEM Channel 9 to 6500 color, and MEM Channel 10 to 7800 color. ( our 6500 parameter is x = 313 ±28, y = 329 ±28, Y = 200 ±10 cd/m2 , 7800 parameter is x = 296 ±28, y = 311 ±28, Y = 200 ±10 cd/m2)

  • Page 40: Edid Content

    AOC LM927U 9. EDID Content 112:...

  • Page 41: Bom List

    AOC LM927U 11. BOM List T980KAQDBCA7B Location Part NO for TPV Description Quantity Unit Q1G 330 8120 SCREW 3X8mm AUPC980A3T AUDIO BOARD CBPC980KAQAC2 CONVERSION BOARD FOR T9 KEPC980KA1 KEY BOARD FOR T980K PWPC1942AUE2 POWER BOARD ASS'Y USB991A2 USB BOARD 11G6038 1...
  • Page 42 AOC LM927U 70G160061515C CD MANUAL 80L L19 1 SP ADAPTOR USB 5V 2.5A 85G 651 3 SHIELD 89G 173 56507 AUDIO CABLE 89G 175504 USB CABLE 89G1738LAA D1 SIGNAL CABLE 89G404A18N YH POWER CABLE 95G8014 16 7 HARNESS 95G8018 30 21...
  • Page 43 AOC LM927U C115 65G0603103 32 0.01UF +-10% 50V X7R C117 65G0603102 32 1000PF +-10% 50V X7R C118 65G0603102 32 1000PF +-10% 50V X7R C120 65G0603102 32 1000PF +-10% 50V X7R C121 65G0603104 12 CER2 0603 X7R 16V 100N C122 65G0603104 12...
  • Page 44 AOC LM927U CN301 88G 35315FHAS D-SUB 15PIN CN503 33G801724A H PIN HEADER 24P 2.0mm CN601 33G8022 14 H PIN EADER CN602 33G8027 16 WAFER 16PIN 2.0mm DIP U601 56L1125137AS4 W78E65P-40 BY WINBOND X401 93G 22 53 CRYSTAL 14.318MHzHC-49U X601 93G 22 55 H...
  • Page 45 AOC LM927U C411 65G0603104 32 CHIP 0.1UF 50V X7R C412 65G0603104 32 CHIP 0.1UF 50V X7R C413 65G0603104 32 CHIP 0.1UF 50V X7R C414 67G 312100 3 SMD 10UF +-20% 16V C415 65G0603104 32 CHIP 0.1UF 50V X7R C416 65G0603104 32 CHIP 0.1UF 50V X7R...
  • Page 46 AOC LM927U D301 93G 6433P BAV99 D302 93G 6433P BAV99 D303 93G 6433P BAV99 D304 93G 64 42 P BAV70 SOT-23 D317 93G 39147 TZMC5V6 D318 93G 39147 TZMC5V6 D319 93G 39147 TZMC5V6 D320 93G 39147 TZMC5V6 D321 93G 39147...
  • Page 47 AOC LM927U R209 61L0603000 RST SM 0603 JUMP MAX 0R R211 61L0603103 RST SM 0603 RC0603 10K R212 61L0603472 RST SM 0603 RC0603 4K7 R301 61L0603510 CHIP 51 OHM 5% 1/10W R302 61L0603510 CHIP 51 OHM 5% 1/10W R303 61L0603510...
  • Page 48 AOC LM927U R614 61L0603103 RST SM 0603 RC0603 10K R615 61L0603103 RST SM 0603 RC0603 10K R616 61L0603472 RST SM 0603 RC0603 4K7 R617 61L0603471 CHIPR 470 OHM+-5% 1/10W R618 61L0603471 CHIPR 470 OHM+-5% 1/10W R619 61L0603472 RST SM 0603 RC0603 4K7...
  • Page 49 AOC LM927U SW103 77L 604 2 TO TACT SW BY TOUKE TS-9-T SW104 77L 604 2 TO TACT SW BY TOUKE TS-9-T SW105 77L 604 2 TO TACT SW BY TOUKE TS-9-T PWPC1942AUE2 705L 980 65 02 19" C901 ASS'Y...
  • Page 50 AOC LM927U D902 93G 6038T52T FR103 F901 84G 7H200 SL 250V/2A LIHEL FUSE IC902 56G 139 3A PC123Y22FZOF L101 73G 253152 T CHOKE COIL TDK LSHAOO3C L201 73G 253139 HA CHOKE COIL L202 73G 253139 HA CHOKE COIL L203 73G 174 35YSA...
  • Page 51 AOC LM927U C225 65G0805105 27 CHIP 1UF Y5V 0805 C320 65G0603331 32 CHIP 330PF 50V X7R C321 65G0603331 32 CHIP 330PF 50V X7R C908 65G0805104 32 CHIP 0.1U 50V X7R C910 65G0805102 31 1000PF 50V NPO C911 65G0805104 32 CHIP 0.1U 50V X7R...
  • Page 52 AOC LM927U R108 61L0603473 RST SM 0603 RC0603 47K R109 61L0603302 CHIPR 3K OHM +-5% 1/10W R110 61L0603360 1F CHIP 3.6KOHM 1% 1/10W R113 61L0603101 RST SM 0603 RC0603 100R R114 61L0603102 RST SM 0603 RC0603 1K P R115 61L0603220...
  • Page 53 AOC LM927U U201 56L 608 1 TL1451ACD ZD901 93G 39S 12 T RLZ20B LLDS ZD902 93G 39S 17 T RLZ12B LLDS 715L1142 3AUE C101 67G215B4713KT LOW ESR 470UF16V BY HER C106 67G215B4713KT LOW ESR 470UF16V BY HER C108 67G215B4713KT LOW ESR 470UF16V BY HER...
  • Page 54 AOC LM927U R203 61G 60210352T CFR 10KOHM +-5% 1/6W R204 61G 60210352T CFR 10KOHM +-5% 1/6W R205 61G 60247352T 47KOHM 5% 1/6W R206 61G 60247352T 47KOHM 5% 1/6W R210 61G 60215352T 15KOHM 5% 1/6W R211 61G 60215352T 15KOHM 5% 1/6W...
  • Page 55 AOC LM927U 90G6081500 HEAT SINK M1G1730 8128 SCREW M3x8 D910 93G 60237 SRF20100C D911 93G 60237 SRF20100C 96G 29 1 SHRINK TUBE UL/CSA USB991A2SMT USB BOARD FOR SMT 705L980KR33 01 19" COVER ASS'Y CNU101 88L 351 2 USB COW REV:2.0 B TYPE...
  • Page 56 AOC LM927U CU116 65G0603104 32 CHIP 0.1UF 50V X7R CU117 65G0603104 32 CHIP 0.1UF 50V X7R CU118 65G0603104 32 CHIP 0.1UF 50V X7R CU119 65G0603104 32 CHIP 0.1UF 50V X7R CU120 65G0603104 32 CHIP 0.1UF 50V X7R CU121 65G0603104 32 CHIP 0.1UF 50V X7R...
  • Page 57 AOC LM927U RU117 61L0603330 CHIPR 33 OHM +-5% 1/10W RU118 61L0603330 CHIPR 33 OHM +-5% 1/10W RU119 61L0603330 CHIPR 33 OHM +-5% 1/10W RU120 61L0603330 CHIPR 33 OHM +-5% 1/10W RU121 61L1206000 RST SM 1206 JUMP MAX 0R UU102 56G 585 4...
  • Page 58 AOC LM927U CNPC980A3 715L1131 1 17 CN301 33G3802 4H WAFER 4P RIGHT ANGLE CN302 33G3802 2H WAFER 2P RIGHT ANGLE CN303 33G3802 2H WAFER 2P RIGHT ANGLE FB301 71G 55502 CORE RF BEAD FB302 71G 55502 CORE RF BEAD...

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