AOC LM725 Service Manual
  1. Manuals
  2. Brands
  3. AOC Manuals
  4. Monitor
  5. LM725
  6. Service manual

AOC LM725 Service Manual

17” lcd monitor
Hide thumbs
Table of Contents

Advertisement

Quick Links

AOC LM725
SERVICE MANUAL
17" LCD MONITOR
LM725
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.
1

Advertisement

Table of Contents
loading

Related Manuals for AOC LM725

Summary of Contents for AOC LM725

  • Page 1 AOC LM725 SERVICE MANUAL 17” LCD MONITOR LM725 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,...

  • Page 2: Table Of Contents

    AOC LM725 Table of Content Revision List…………………………………………………………………………………………………………. 1. Monitor Specifications………………………………………………………………………………………….. 2. LCD Monitor Description……………………………………………………………………………………….. 3. Operating Instructions………………………………………………………………………………………….. 3.1 General Instructions…………………………………………………………………………………………... 3.2 Front Panel Control…………………………………………………………………………………….……... 3.3 Adjusting the Picture………………………………………………………………………………………….. 4. Input/Output Specification……………………………………………………………………………………... 4.1 Input Signal Connector……………………………………………………………………………………….. 4.2 Factory Preset Display Modes………………………………………………………………………………..

  • Page 3: Revision List

    AOC LM725 Revision List Version Date Revision History TPV Model Name Mar-09-06 Initial Revision T782KSQHMCPGA...

  • Page 4: Monitor Specifications

    AOC LM725 1. Monitor Specifications Items Description Driving system TFT Color LCD Type LTM170EU-L21 Size 43.2cm (17.0") LCD Panel Pixel pitch 0.264mm (H) x 0.264mm (V) Viewable angle 150(H) 135(V) (CR≥10) Response time (type) 8 ms Sync. Type H/V TTL...

  • Page 5: Lcd Monitor Description

    AOC LM725 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 LM725 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 7: Adjusting The Picture

    AOC LM725 3.3 Adjusting The Picture The Description For Control Function: Main Main Menu Item Menu Sub Menu Item Menu Description Reset Value Icon Icon Recall Cool Contrast Contrast from Digital-register. Contrast Value Luminance Recall Cool Brightness Backlight Adjustment Brightness Value...
  • Page 8 AOC LM725 Adjust the horizontal position of the H. Position OSD. Adjust the vertical position of the OSD Setup V. Position OSD. OSD Timeout Adjust the OSD timeout. English Set OSD display language to English. Set OSD display language to Deutsch German.

  • Page 9: Input/Output Specification

    AOC LM725 4. Input/Output Specification 4.1 Input Signal Connector Pin No. Description Pin No. Description Green Logic Ground Blue Monitor Ground Monitor Ground DDC-Serial Data DDC-Return H-Sync R-Ground V-Sync G-Ground DDC-Serial Clock B-Ground VGA connector layout...

  • Page 10: Factory Preset Display Modes

    AOC LM725 4.2 Factory Preset Display Modes VESA MODES Horizontal Vertical Nominal Sync Nominal Sync Nominal Frequenc Polarity Freq. Polarity Pixel Mode Resolution Total +/- 1 Hz Clock +/- 0.5kHz (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 LM725 4.3 Power Supply Requirement A/C Line voltage range 100 V ~ 240 V 50 ± 3Hz, 60 ± 3Hz A/C Line frequency range Peak surge current < 55A peak at 240 VAC and cold starting Leakage current < 3.5mA...

  • Page 12: Optical Characteristics

    AOC LM725 4.4.3 Optical Characteristics * Ta = 25 ± 2°C, VDD=5V, fv= 60Hz, fDCLK=54MHz, IL = 6.5mArms...

  • Page 13: Electrical Characteristics

    AOC LM725 4.4.4 Electrical Characteristics 1. TFT LCD Module: 2. Back Light Unit:...

  • Page 14: Block Diagram

    AOC LM725 5. Block Diagram 5.1 Monitor Exploded View...

  • Page 15: Software Flow Chart

    AOC LM720A 5.2 Software Flowing Chart...
  • Page 16 AOC LM720A 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 17: Electrical Block Diagram

    AOC LM720A 5.3 Electrical Block Diagram 5.3.1 Main Board Crystal LCD Interface 20MHZ (CN503) (X601) Scalar IC MST8131B W78E65 (Include ADC, OSD) (U601) (U401) EPR_SDA EPR_SCL H sync D-Data V sync EEPROM Key Board D-Clock 24LC16B Control (U602) D-Sub D-Sub Crystal 14.318MHZ...

  • Page 18: Inverter/Power Board

    AOC LM720A 5.3.2 Inverter/Power Board AC input Bridge Rectifier Transformer Rectifier diodes EMI filter and Filter Start Circuit: R906、 R907 CN102 Feedback Over Voltage Circuit Control IC Protect ON/OFF OSC and MOSFET DC Convert Output Circuit Circuit Lamp Over ON/OFF...

  • Page 19: Schematic

    VAA1 VLCD VAA2 VAA3 VAA4 VCC5V onBACKLITE 5.PANEL INTERFACE onPanel_5V/3.3V VCPU VCC12V VCC3.3 VCC2.5 AdjBACKLITE AdjBACKLITE VAA1 VLCD VAA2 VAA3 VAA4 VCC5V Title VLCD 4.SCALER MST8031 / MST8131 for AOC Size Document Number 2.POWER Date: Wednesday, April 14, 2004 Sheet...
  • Page 20 DAT4- DAT5+ DAT5- clk+ CLK+ clk- CLK- JACK D306 D307 D308 D309 D310 D311 D312 D313 BAV99 BAV99 BAV99 BAV99 BAV99 BAV99 BAV99 BAV99 VCC5V Title MST8031/ MST8131 for AOC Size Document Number INPUT Date: Tuesday, November 09, 2004 Sheet...
  • Page 21 14.318MHz XOUT VAA4 C403 22pF 600 OHM BUS TYPE/NC C404 0.1uF C427 BYPASS R401 10uF/16V AVSS_LPLL C428 0.1uF R402 R401 Direct Bus 4.7K Title MST8031/ MST8131 for AOC 4.7K 3-WIRE Size Document Number SCALER Date: Wednesday, April 14, 2004 Sheet...
  • Page 22 RXE3+ LVA3P LVB3M LVBCKP LVBCKM LVB2P LVB2M CONN R502 LVB1P 　 LVB1M 1/16W LVB0P VLCD LVB0M VLCD C509 C510 C511 47uF/16V 0.1uF 0.1uF Title MST8031 / MST8131 for AOC Size Document Number PANEL INTERFACE Date: Wednesday, April 14, 2004 Sheet...
  • Page 23 R623 470 1/16W POWER 　 R624 1/16W Mute_key OUT-R+ C606 C608 C610 OUT-L+ C616 C609 OUT-L- OUT-R- C607 0.001uF 0.001uF 0.001uF 1uF/25V 0.001uF 0.001uF CONN Title MST8031 / MST8131 for AOC Size Document Number Date: Wednesday, July 21, 2004 Sheet...

  • Page 24: Power Board

    AOC LM725 6.3 Power Board 715L1103- 217A...
  • Page 25 AOC LM725  ...

  • Page 26: Audio Board

    AOC LM725 6.2 Audio Board 715L1144-1-IO OUT_L OUT_R +12V PIN-3 CN202 WAFER 2*7P 2.54mm MUTE PIN-1 VOLUME C202 C201 C203 470uF/16V 470uF/16V 0.1uF U201 PIN-1 TDA7496L CN204 C205 CN203 C204 0.47uF R201 10K　 OUTL 470uF/16V C206 0.47uF OUTR R203 10K　...

  • Page 27: Pcb Layout

    AOC LM725 7. PCB Layout 7.1 Main Board 715L1237-1...

  • Page 28: Power Board

    AOC LM725 7.2 POWER BOARD 715L1103-217A...

  • Page 29: Audio Board

    AOC LM725 7.3 Audio Board 715L1144-1-IO 7.4 Key Board 715L1222-4-C3...

  • Page 30: Maintainability

    AOC LM725 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 31: Trouble Shooting

    AOC LM725 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 Adapter/Inverter section Measure U201 PIN2=2.5V U202 PIN2=3.3V...
  • Page 32 AOC LM725 No picture (LED orange) No picture The button if X601 oscillate Replace X601 under control waveform is normal Check reset circuit of Check Correspondent component U601 is normal Measure U201 PIN2=2.5V U202 PIN2=3.3V Replace U601 Replace U201, U202...
  • Page 33 AOC LM725 White screen White screen Measure Q204 base X601 oscillate waveform is normal is low level? Replace X601 Check Q204 is broken or Check reset circuit of CN503 solder? U601 is normal Check Correspondent Check Correspondent component. component. Replace PANEL...

  • Page 34: Power/Inverter Board

    AOC LM725 8.2.2 Power/Inverter Board 1) No power Check CN102 pin12 = 12V Check AC line volt 110V or 220V Check AC input Check the voltage of C905 (+) Check bridge rectified circuit and F901 circuit Check start voltage for the pin3 of IC901...
  • Page 35 AOC LM725 2.) No Backlight Check CN102 pin12 =12V Check adapter Check ON/OFF signal Check Interface board or main board Check U201 pin9=12V Change Q201 or Q202 Check U201 PIN10,7 have the output of sawtooth wave at short time Change U201 Check D201(-), D202(-) have the output of square wave at short time.

  • Page 36: Keypad Board

    AOC LM725 8.2.3 Keypad Board OSD is unstable or not working Is Key Pad Board connecting normally? Connect Key Pad Board Replace Button Switch Is Button Switch normally? Replace Key Pad Board Is Key Pad Board normally? Check Main Board...

  • Page 37: White-Balance, Luminance Adjustment

    6500 color temp. parameter is x = 313±20, y = 329 ±20, Y =180 cd/m 3. Into factory mode of LM725 Turn on power, press the MENU button, pull out the power cord, and then plug the power cord. Then the factory OSD will be at the left top of the panel.

  • Page 38: Edid Content

    AOC LM725 10. EDID Content 1. Analog EDID 112: 2.Digital EDID...

  • Page 39: Bom List

    AOC LM725 11. BOM List T782KSQHMCPGA Location Part No. for TPV Description Quantity Unit 45G 76 28 RN PE BAG FO MANUAL/BASE AUPC780A9 AUDIO BOARD CBPC782KSQAW COVERSION BOARD KEPC780KD2 KEY BOARD PWPC7425A3E12 POWER BORD 15G5786 1 VRSA BRACKET 15G5908 2...
  • Page 40 AOC LM725 M1G1140 6128 SCREW 4X6 M1G1730 6128 SCREW M3x6 Q1G 330 8120 SCREW 3X8mm Q1G 330 10 47 SCREW Q1G 330 12 47 SCREW 705L782KF34 32 BEZEL ASS'Y AM1G1740 10 47 SCREW T34G1455 72 B BASE E089B 89G 718LAA D...
  • Page 41 AOC LM725 C211 65G0805101 31 CHIP 100PF 50V NPD 0805 C212 65G0805101 31 CHIP 100PF 50V NPD 0805 C213 65G0805104 32 CHIP 0.1U 50V X7R R201 61L0603183 CHIP 18K OHM 1/10W R203 61L0603183 CHIP 18K OHM 1/10W R207 61L0603102 RST SM 0603 RC0603 1K P...
  • Page 42 AOC LM725 C307 65G0603102 32 1000PF +-10% 50V X7R C308 65G0603473 32 CHIP 0.047UF 50V X7R C309 65G0603473 32 CHIP 0.047UF 50V X7R C310 65G0603473 32 CHIP 0.047UF 50V X7R C311 65G0603330 31 CER1 0603 NP0 50V 33P P C312...
  • Page 43 AOC LM725 C607 65G0603102 32 1000PF +-10% 50V X7R C608 65G0603102 32 1000PF +-10% 50V X7R C609 65G0603102 32 1000PF +-10% 50V X7R C610 65G0603102 32 1000PF +-10% 50V X7R C611 65G0805105 22 CHIP 1UF 25V X7R 0805 C612 65G0603104 32 CHIP 0.1UF 50V X7R...
  • Page 44 AOC LM725 FB403 71G 56Z601 CHIP BEAD 600 OHM 0805 FB404 71G 56Z601 CHIP BEAD 600 OHM 0805 FB405 71G 56Z601 CHIP BEAD 600 OHM 0805 FB406 71G 56Z601 CHIP BEAD 600 OHM 0805 FB601 71G 56Z601 CHIP BEAD 600 OHM 0805...
  • Page 45 AOC LM725 R315 61L0603101 RST SM 0603 RC0603 100R R316 61L0603101 RST SM 0603 RC0603 100R R317 61L0603103 RST SM 0603 RC0603 10K R318 61L0603103 RST SM 0603 RC0603 10K R319 61L0603101 RST SM 0603 RC0603 100R R320 61L0603101 RST SM 0603 RC0603 100R...
  • Page 46 AOC LM725 R624 61L0603102 RST SM 0603 RC0603 1K P R625 61L0603103 RST SM 0603 RC0603 10K R626 61L0603103 RST SM 0603 RC0603 10K R627 61L0603103 RST SM 0603 RC0603 10K R634 61L0603101 RST SM 0603 RC0603 100R R635 61L0603101...
  • Page 47 AOC LM725 705L 780 57 18 D910/D912 ASS'Y 705L 780 5702A Q903 ASS'Y BD901 93G 50460502 KBP206G C215 65G 3J2206ET 22PF 5% SL 3KV TDK C216 65G 3J2206ET 22PF 5% SL 3KV TDK C217 65G 3J2206ET 22PF 5% SL 3KV TDK...
  • Page 48 AOC LM725 C203 65G0805105 27 CHIP 1UF Y5V 0805 C209 65G0805105 27 CHIP 1UF Y5V 0805 C210 65G0805105 27 CHIP 1UF Y5V 0805 C211 65G0805105 27 CHIP 1UF Y5V 0805 C212 65G0805105 27 CHIP 1UF Y5V 0805 C219 65G0805105 27...
  • Page 49 AOC LM725 R902 61L1206105 CHIP 1MOHM 5% 1/4W R904 61L1206105 CHIP 1MOHM 5% 1/4W R905 61L1206105 CHIP 1MOHM 5% 1/4W R906 61L1206754 CHIP 750KOHM 5% 1/4W R907 61L1206754 CHIP 750KOHM 5% 1/4W R909 61L1206472 CHIP 4.7KOHM 5% 1/4W R910 61L1206472 CHIP 4.7KOHM 5% 1/4W...
  • Page 50 AOC LM725 C908 65G 450104 7T 0.1UF +80-20% 50V Y5V C909 64G700J1040AT 0.1UF 50V PEN C911 64G700J1020AT 1000PF 50V PEN C920 65L517K102 5T6213 1000PF 10% Y5P 500V C921 65L517K102 5T6213 1000PF 10% Y5P 500V C924 67G215B4713HT 470UF 16V LTR471M1CF11V C926...
  • Page 51 AOC LM725 R218 61G 60210152T 100OHM +- 5% 1/6W R219 61G 60210152T 100OHM +- 5% 1/6W R220 61G 60215352T 15KOHM 5% 1/6W R221 61G 60215352T 15KOHM 5% 1/6W R222 61G 60212352T 12KOHM 5% 1/6W R223 61G 60212352T 12KOHM 5% 1/6W...

Table of Contents