AOC 786LS Service Manual
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AOC 786LS Service Manual

AOC 786LS Service Manual

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SERVICE MANUAL
17" LCD Monitor
786LS

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  • Page 1 All manuals and user guides at all-guides.com SERVICE MANUAL 17" LCD Monitor 786LS...
  • Page 2 All manuals and user guides at all-guides.com 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, MANUFACTURE DATA : Aug 28 2002 REVISE:...

  • Page 3: Table Of Contents

    All manuals and user guides at all-guides.com TABLE OF CONTENTS PAGE 1. SPECIFICATIONS ....................GENERAL SPECIFICATIONS ...........…....LCD MONITOR DESCRIPTION ..............INTERFACE CONNECTOR ..............……. 2. PRECAUTION AND NOTICES ................ASSEMBLY PRECAUTION ................. OPERATIONG PRECAUTION ..............STORAGE PRECAUTION …................ HIGH VOLTAGE WARNING ............... 3.

  • Page 4: Specifications

    All manuals and user guides at all-guides.com 1. SPECIFICATIONS FOR LCD MONITOR General specifications 1. LCD-Panel : Active display area 17 inches diagonal 0.264 mm x 0.264 mm Pixel pitch Pixel format 1280 x 1024 RGB vertical stripe arrangement 2. Display Color : 6-bit, 16.2 million colors 3.

  • Page 5: Interface Connector

    All manuals and user guides at all-guides.com LCD MONITOR DESCRIPTION The LCD MONITOR will contain an main board, an Inverter module, keyboard, External Adapter which house the flat panel control logic, brightness control logic, DDC and DC-DC conversion The Inverter module will drive the backlight of panel . The Adapter will provides the 12V DC-power 4.16 Amp to Main-board,and Inverter module .

  • Page 6: Precaution And Notices

    All manuals and user guides at all-guides.com 2. PRECAUTIONS AND NOTICES ASSEMBLY PRECAUTION (1) Please do not press or scratch LCD panel surface with anything hard. And do not soil LCD panel surface by touching with bare hands ( Polarizer film, surface of LCD panel is easy to be flawed) In the LCD panel, the gap between two glass plates is kept perfectly even to maintain display characteristic and reliability.

  • Page 7: Operating Instructions

    All manuals and user guides at all-guides.com 3. OPERATING INSTRUCTIONS This procedure gives you instructions for installing and using the LCD monitor display. Position the display on the desired operation and plug–in the power cord into External Adapter AC outlet. Three-wire power cord must be shielded and is provided as a safety precaution as it connects the chassis and cabinet to the electrical conduct ground.

  • Page 8: Adjustment

    All manuals and user guides at all-guides.com 4. ADJUSTMENT ADJUSTMENT CONDITIONS AND PRECAUTIONS Adjustments should be undertaken only on following function : Contras , Brightness, Black level, Phase, Clock , H/V-position , Languages, Color-(7200,6500,User), Auto level, OSD-position, Languages, Reset ADJUSTMENT METHOD Press MENU button to activate OSD Menu or make a confirmation on desired function, Press Left/Right button to select the function or done the adjustment.
  • Page 9 All manuals and user guides at all-guides.com Gain adjustment : adjust 7200 color-temperature Set the Contrast of OSD function to 45 and Adjust Brightness to chroma 7120 Y=240 ±5 cd/m Switch the chroma-7120 to RGB-mode (with press “MODE” button ) Switch the MEM.channel to Channel 01 ( with up or down arrow on chroma 7120 ) The lcd-indicator on chroma 7120 will show x = 302 ±10, y = 319 ±10, Y = 200 ±5 cd/m Adjust the Color(user)Mode: RED on OSD window, until chroma 7120 indicator reached the value...

  • Page 10: Front Panel Control Knobs

    All manuals and user guides at all-guides.com Clock adjustment Set the Chroma at pattern 63 (cross-talk pattern) or WIN98/95 shut-down mode (dot-pattern). Adjust until the vertical-Stripe-shadow as wide as possible or no visible. This function is adjust the PLL divider of ADC to generate an accurate pixel clock Example : Hsyn = 31.5KHz Pixel freq.

  • Page 11: Circuit & Software Description

    All manuals and user guides at all-guides.com 5. CIRCUIT-DESCRIPTION SPECIAL FUNCTION WITH PRESS-KEY A). press Menu button during 2 seconds along with plug-in the DC Power cord: That operation will set the monitor into “Factory- mode”, in Factory mode we can do the White balance adjustment with RS232 In Factory mode, OSD-screen will locate in left top of screen.
  • Page 12 All manuals and user guides at all-guides.com MODULE-TPYE COMPONENT: 1. ADAPTER : CONVERSION-module to convert AC 110V-240V to 12VDC, with 4.16 AMP 2. INVERTER : CONVERSION-module to convert DC 12V to High-Voltage around 1650V, with frequency 30K-80Khz, 5.6mA-13mA Main-board Block diagram Input analog RGB &...

  • Page 13: Software Flow Chart

    All manuals and user guides at all-guides.com SOFTWARE FLOW CHART Power-On Subroutine CHART POWER-ON START Initial MCU I/O, Interrupt vector & Ram Initial 1.POC (backlight counter) Check Eeprom is empty ? 2. Clr all mode value Check White-balance data(6500 & 7200) same with the backup data ? Check POC( backlight counter) data same with the backup data ? IF not same, overwrite the data with backup value.
  • Page 14 All manuals and user guides at all-guides.com MAIN SUBROTINE LOOP Main loop start Process Power-saving status ( according to below flow-chart result) Check GMZAN2 IFM status .is change or not. And check Signal cable status ( cable not connected or not ) ** IFM is the register which measured the HSYN &...

  • Page 15: Interface-Board Trouble-Shooting Chart

    All manuals and user guides at all-guides.com 6 A). INTERFACE-BOARD TROUBLE-SHOOTING CHART *Use the PC Win 98 white pattern, with some icon on it, and Change the Resolution to 640x480 60 Hz / 31 KHz **NOTICE : The free-running freq. of our system is 48 KHz / 60 Hz, so we recommend to use another resolution to do trouble shooting, this trouble shooting is proceed with 640x480 @60Hz 31Khz NO SCREEN APPEAR DC-Power Part...
  • Page 16 All manuals and user guides at all-guides.com PANEL-POWER CIRCUIT Check the PPWR panel power relative circuit, R223,R224, Q200,U202(pin 5,6,7,8) In normal operation, when LED =green, R223 check R225 should have response from 0V to 5V should =0 v, When we switch the power switch from on to off If PPWR no-response when the power switch Turn on and turn off, replace the U200-GMZAN2 OK,R225 have response...
  • Page 17 All manuals and user guides at all-guides.com II (a) THE SCREEN is Abnormal , stuck at white screen, OSD window can’t appear, but keyboard & LED was normal operation. At general, this symptom is cause by missing panel data or panel power, so we must check our wire-harness which connected to panel or the panel power controller (U202) Check if the Wire harness from CN603 loose? Tighten it.
  • Page 18 All manuals and user guides at all-guides.com II. (b)The screen had the Vertical Straight Line, might be stuck in Red, Green, Blue That symptom is cause by bad Panel issue ( might be the Source IC from Panel is cold solder or open loop ) so REPLACE THE PANEL TO NEW ONE.
  • Page 19 All manuals and user guides at all-guides.com POWER-BLOCK check *Note : the Waveform of U304 pin 2 can determined the power situation 1. stable rectangle waveform with equal duty, freq around 150K-158KHz that means all power of this interface board is in normal operation ,and all status of 5V &...
  • Page 20 All manuals and user guides at all-guides.com III.ALL SCREEN HAS INTERFERENCES OR NOISE, CAN’T BE FIXED BY AUTO KEY ** NOTE: There is so many kind of interferences, 1). One is cause by some VGA-CARD that not meet VESA spec or power grounding too bad that influence our circuit 2).other is cause by external interferences, move the monitor far from electronic equipment.( rarely happened)
  • Page 21 All manuals and user guides at all-guides.com There is interferences in DOS MODE NOTE :the criteria of doing AUTO-CONFIGURATION : must be a full-size screen, if the screen not full , the auto- configuration will fail. So in dos mode ,just set your “CLOCK” in OSD-MENU to zero or use some EDITOR software which can full fill the whole screen (ex: PE2, HE) and then press “AUTO”...

  • Page 22: Inverter -Module Spec &Trouble Shooting Chart

    All manuals and user guides at all-guides.com 6 B). INVERTER –MODULE SPEC &TROUBLE SHOOTING CHART For 786LS model , use Hydis panel, and the INVERTER is made by SAMPO SAMPO Parts No: DIVTL0085-D42 AOC Parts No.: 79LL17-3-S CONNECTOR PIN ASSIGMENT: A) CON1: INPUT MODEL NO.: S5B-PH-SM3-TB...
  • Page 23 All manuals and user guides at all-guides.com D) FUNCTION TEST CIRCUIT: 120KΩ 120KΩ CON4 CON2 10Ω 10Ω CON5 CON3 CON1 VT-181 1 2 3 4 5 120KΩ 120KΩ 10Ω 10Ω VT-181...
  • Page 24 All manuals and user guides at all-guides.com II. TROUBLE SHOOTING BLOCK DIAGRAM NO POWER: CHECKED ON FUSE TO CHANGED F1 Vin=12 FAIL F1= 4.0A/63V TO CHECKED Q4 & Q6 TO CHANGED PASS FAIL VOUT = 9V CH1: Q4/Q3/Q11 CH2: Q5/Q6/Q12 TO CHECKED L1/L2 PASS INPUT 9V TO L1 OR L2...
  • Page 25 All manuals and user guides at all-guides.com C) OUTPUT CURRENT ABNORMALITY: CHECK PWM FREQUNCY AT C6 FAIL TO CHANGE C6 CHIP OR IC CHIP CHIP THE OSCILLATOR FREQUNCY RANGE = 150 ~ 250 KHZ PASS FUNCTION TEST OK! ENBALE ABNORMALITY: IF ENABLE ABNORMALITY TO CHANGE ON Q1 1.
  • Page 26 All manuals and user guides at all-guides.com TRANSFORMER ABNORMALITY: IF TRANSFORMER ABNORMELITY TO CHECK FAIL TO CHANGE C3 & C4 OR C3 & C4 CHIP OUTLINE OR TRANSFORMER TRANSFORMER PASS FUNCTION TEST OK! G) INSTRUMENTS FOR TEST: DC POWER SUPPLY GPS-3030D AC VTVM VT:-181E...

  • Page 27: Mechanical Of Cabinet Front Dis-Assembly

    All manuals and user guides at all-guides.com MECHANICAL OF CABINET FRONT DIS-ASSEMBLY...

  • Page 28: Svc_Bom Listing For Lge Part No

    All manuals and user guides at all-guides.com SVC_BOM LISTING FOR LGE PART NO 786LS SVC BOM LG Part No. Desc. AOC Part No. Desc. Q'TY 3911TKK425B Main Board Ass'y CBPC782KKGLM Main Board Ass'y ( = Conversion Board ) 3911TKK425C Control Board Ass'y...
  • Page 29 All manuals and user guides at all-guides.com LCD PANEL HT17E11- 3911TKK425A LCD Panel 750LLK70-300 95L 900 3911TKK425H 31(Harness) Connector (Power) 95L8018-30- P980 5(harness) 3911TKK425J Connector (Panel) CN603 33L801724A H 3911TKK425K CN302 33L3802 9H Connector (Key) 3911TKK425L Cn303 33L3802 5H Connector (Inverter) Screw Screw Assy M1L330-6-128...

  • Page 30: Power System And Consumption Current

    All manuals and user guides at all-guides.com POWER SYSTEM AND CONSUMPTION CURRENT ADAPTER MODULE INVERTER MODULE Input AC 110V, 60Hz/240V, 50Hz Input DC 12V Output DC 12V 5A Output AC 1500V/30K-80KHz Current 14mA Main board power system LM2596S-5, 12V to 5V (5A SPEC) To CPU, Eeprom, 24c21, control-inverter-on.off 860mA when Cable not Connected 841mA when Normal operation...

  • Page 31: Pcb Layout

    All manuals and user guides at all-guides.com PCB LAYOUT MAIN PCB LAYOUT DDC chip RT9164 LVDS power ( LT1117) 5V to 2.5v 5V to 3.3v Input Connector LVDS Gmzan2 AIC1084 5V to 3.3v Panel- Power Control Inverter-connector Keyboard-connector LM2596 convert 12V to 5V Audio-connector...
  • Page 32 All manuals and user guides at all-guides.com 11. SCHEMATIC DIAGRAM TOP-LEVEL FLOW Power block POWER +3.3V +3.3V +12V +2.5V +2.5V +5.0V +3.3V +2.5V AIC1084-3.3V RT9164-2.5V LM2596-5.0V .Gmzan2 block LVDS block +3.3V PANEL(HYUNDAI-300) SCALER ZAN2 LVDS1 ERED ERED[0-7] INPUT EGRN EGRN[0-7] TX0-/+E TX0-/+E EBLU...
  • Page 33 All manuals and user guides at all-guides.com +D5V +3.3V GMZAN2 Block +3.3V L200 C956 DVDDA 1000pF +B2.5V +A2.5V 600(1206) C200 C201 C202 DVDDA SVDDA RVDDA R221 VDDA RP300 100uF 0.1 uF 0.1 uF 10 K PGND U200 L201 SVDDA 600(1206) C203 C204 C205...
  • Page 34 All manuals and user guides at all-guides.com AVDD_3.3 LVDS Block C601 C602 C603 EVEN 0.1uF 0.1uF 100uF U601 NT7181 TSSOP56 EDGE PD36 PD36 TXIN0 PWRDWN PD37 PD37 TXIN1 TX0-E TXE0 TXIN2 TXOUT0- TXE1 TX0+E PD[0..5] TXIN3 TXOUT0+ TX1-E TXE2 TXIN4 TXOUT1- TX1+E TXE3...
  • Page 35 All manuals and user guides at all-guides.com MCU Block R431 R239 R235 10 K(OP) 4.7K(OP) 4.7K(OP) R238 0 MUTE 8XC51/PLCC (Panel-Select)* ? STDBY U302 R319 K/E Select Q201 R237 0 HDATA0 T2/P1.0 P2.0/A8 MFB7 T2EX/P1.1 P2.1/A9 MFB8 P1.2 P2.2/A10 R236 10 K(OP) MFB9 P1.3 P2.3/A11...
  • Page 36 All manuals and user guides at all-guides.com +12V U304 LM2596S-5.0 / Si8050 FB301 +12V POWER TO263 Vout T300 C307 C308 330 uF/35V 0.1 uF C309 D300 33 uH(OP) 330 uF/35V C941 INDUCTOR-P B320 0.1 uF L906 GND F CHOKE POWER Block JP301 (OP) +A5V...

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