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Website:http://biz.LGservice.com
E-mail:http://www.LGEservice.com/techsup.html
COLOR MONITOR
SERVICE MANUAL
CHASSIS NO. : CL-29
FACTORY MODEL: LB782G
MODEL: LCD 782LS (LB782G-GD)
*( ) ID LABEL MODEL No.
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
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CONTENTS SPECIFICATIONS ................................................... 2 ADJUSTMENT ....................................................... 11 PRECAUTIONS ....................................................... 3 TROUBLESHOOTING GUIDE .............................. 12 TIMING CHART ....................................................... 4 PRINTED CIRCUIT BOARD................................... 17 OPERATING INSTRUCTIONS ................................ 5 EXPLODED VIEW........................
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PRECAUTION WARNING FOR THE SAFETY-RELATED COMPONENT. WARNING • There are some special components used in LCD BE CAREFUL ELECTRIC SHOCK ! monitor that are important for safety. These parts are • If you want to replace with the new backlight (CCFL) or marked on the schematic diagram and the inverter circuit, must disconnect the AC adapter replacement parts list. It is essential that these critical because high voltage appears at inverter circuit about parts should be replaced with the manufactu
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TIMING CHART VIDEO B A E C F D SYNC << Dot Clock (MHz), Horizontal Frequency (kHz), Vertical Frequency (Hz), Horizontal etc... (µs), Vertical etc... (ms) >> Sync H/V DOT Total Period Video Active Front Porch Sync Duration Back Porch Mode Resolution Frequency (F) Polarity Clock (E) Time (A) (C) (D) Sort H + 31.469 800 640 16 96 48 640x350 1 25.175 70Hz V – 70.09 449 350 37 2 60 H – 31.468 900 720 18 108 54 720x400 2 28.321 70Hz V + 70.08 449 400 12 2 35 H – 31.469 800 640 16 96 48 640x480 3 25.
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OPERATING INSTRUCTIONS FRONT VIEW REAR VIEW AUDIO DC OUT Power Connector Power ON/OFF Button Power (DPMS) Indicator D-Sub Signal Port Front Control Panel SET Button MENU Button Button Power Button AUTO Button Power Indicator 1. MENU Button 3. AUTO Button Use this button to enter a selection in the on screen Use this button to enter or exit the on screen display. display. 2. Button * AUTO adjustment function PROCESSING Use these buttons to choose or adjust items in the on AUTO CONFIGURATION T
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WIRING DIAGRAM Connector Ass’y P/No.: 6631T11012W PG4 Connector Ass’y P/No.: 6631T25008R J706 J801 Connector Ass’y P/No.: 6631T20008P J710 J702 CN2 J1 CN1 CN3 Connector Ass’y P/No.: 6631T20015A - 6 -
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DISASSEMBLY BACK COVER REMOVAL Caution: When you open the Back cover, Be careful! Dont stress the Control Board Connector. (a) (b) (b) (b) (b) (a) (a) (b) (b) (a) (b) (b) (b) (b) (b) Latch Point 1) Set the Monitor face downward. 3) Set the Monitor as picture. 2) Remove four screws (a). 4) Release the bottom & side latch. 5) Set the Monitor face upward. 7) Release the center positon latch. 6) Release the up side latch. 8) Set the Monitor face downward. 9) Remove the Back cover. - 7 -
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BLOCK DIAGRAM - 8 - Tx+/-,Hs,Vs,CLK,DEN Module Power (5V) LVDS Tx DC/DC Block GM5020 ADC EEPROM + PLL (SYSTEM) 2.5V Regulator Scaling To Inverter 12V 3.3V Regulator BRT-CTL OSD MCU INV-CTL 12V(Inverter) 12V DDC 90-264V Analog (EDID) POWER BOARD Signal 5.0V (H/V Sync) (R,G,B) H SYNC DSUB AC INPUT SDA, SCL
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DESCRIPTION OF BLOCK DIAGRAM 1. Input signal part. There is one input which is analog. It comes from 15 pin D-Sub connector. 2. Pre-amp/ ADC / PLL / Video Controller. This part amplifies the level of video signal from the analog video signal to the digital video signal using a pixel clock. The pixel clock for each mode is generated by the PLL. The range of the pixel clock is from 25MHz to 135.0MHz. The Scaler gets the video signal converted analog to digital, interpolates input to 1280 X 1024
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BLOCK DIAGRAM POWER BOARD 12V 50 ~ 60Hz 100KHz 5V HVDC EMI INPUT RECTIFIER ENERGY OUTPUT RECTIFIER COMPONENTS AND FILTER TRANSFER AND FILTER GND LINE 100 ~ 240V PWM CONTROL PHOTO-COUPLER SIGNAL CIRCUIT ISOLATION COLLENTION SECONDARY PRIMARY DESCRIPTION OF BLOCK DIAGRAM 1. EMI components. This part contains of EMI components to comply with global marketing EMI standards like FCC the circuit included a line-filter, across line capacitor and of course the primary protection fuse. 2. Input rectifie
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220 VGS MONITOR ADJUSTMENT All adjustment are thoroughly checked and corrected 2. Adjustment for White Balance when the monitor leaves the factory, but sometimes 1) Display Black pattern at SXGA/60Hz. several minor adjustment may be required. 2) Set External Bright to MAX position and Contrast to Adjustment should be following procedure and after 80 Position. warming up for a minimum of 10 minutes. 3) Select PRESET START → BIAS CAL command and Enter. • Alignment appliances and tools. 4) No attem
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TROUBLESHOOTING GUIDE 1. NO POWER NO POWER (POWER INDICATOR OFF) CHECK J801 NO TROUBLE IN INPUT VOLTAGE BULT-IN POWER (12V) ? YES CHECK J801 NO TROUBLE IN 5VST VOLTAGE BULT-IN POWER (5V) ? YES CHECK U501’s PIN 6. NO TROUBLE IN IS THIS PIN U501 or X501 OSCILLATED? YES TROUBLE SOMEWHERE ELSE - 12 -
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2. NO RASTER NO RASTER CHECK NO TROUBLE IN J702 PIN 1, 2, 3 POWER ADATER (12V) ? or L703, L704 YES CHECK NO TROUBLE IN J702 PIN 8 (5V) ? INVON PATTERN YES CHECK NO TROUBLE IN X501 X501 H. PULSE ? YES CHECK NO TROUBLE IN U201(GM5020) ? U201 YES CHECK NO TROUBLE IN L201, L202, L203 U201 PULSE? - 13 -
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YES CHECK NO TROUBLE IN L204 U201 PULSE ? YES CHECK NO CHECK DOT CLOCK U401 PIN 10 PATTERN PULSE ? YES CHECK NO CHECK U401 PIN 8 V.PULSE? DVS PATTERN YES CHECK NO CHECK U401 PIN 7 DHS PATTERN V.PULSE? YES TROUBLE IN LCD MODULE - 14 -
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3. NO CLOCK (CLOCK GENERATOR) NO DOT CLOCK YES CHECK NO TROUBLE IN X201 24MHz ? X201 YES CHECK NO TROUBLE IN L201 U201 CLOCK ? - 15 -
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4. TROUBLE IN DPM TROUBLE IN DPM CHECK PC CHECK NO PC IS NOT GOING R233, R234? INTO DPM OFF MODE YES CHECK NO U501 PIN 6 TROUBLE IN WAVEFORM X501 (24MHz) ? YES CHECK NO TROUBLE IN U501 PIN 11 SIGNAL CABLE (0V) ? YES TROUBLE IN PC - 16 -
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L821 L811 U502 J801 X501 D801 C710 R804 C701 C840 R805 J702 R562 R501 C502 C501 C510 C503 U501 U801 R809 40 U503 C531 30 A C818 R581 U802 R810 R450 C820 C408 R564 R582 R539 C707 C819 A R807 C406 C834 U821 C811 C407 MODEL:LG708G GM5020 P/N :6870T487A11 RA222 RA218 RA212 RA208 RA204 R818 R830 U401 20 R817 R829 C404 R816 R828 C232 C236 R815 R827 R236 R814 R826 R813 R820 DATE :2002.04.03 R403 RA216 R812 R819 RA206 RA224 RA220 C208 RA202 RA214 C210 C234 R811 R831 C212 C224 C231 L201 L204 C871 C217 R
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4. POWER BOARD (Component Side) 5. POWER BOARD (Solder Side) - 18 -
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EXPLODED VIEW a b 3 15 11 13 12 8 7 10 6 9 14 5 4 c 2 1 - 19 -
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EXPLODED VIEW PARTS LIST Ref. No. Part No. Description 1 3091TKL031H CABINET ASSEMBLY, LB782G BRAND ANALOG ONLY EXPORT 2 6304FHD004A LCD(LIQUID CRYSTAL DISPLAY) HT17E11-300 HYUNDAI TFT COLOR SXGA 17 INCH LVDS 3 3809TKL021A BACK COVER ASSEMBLY, LB782F 3808TKL026 PC+ABS 4 3043TKK037M TILT SWIVEL ASSEMBLYLB782F . NO USB 5 4951TKS082F METAL ASSEMBLY, FRAME LB782G -HYDIS MODULE 6 6633TZA011A INVERTER ASSEMBLY, LG-PHILIPS NMC1804,4-LAMP AU MODULE LB782 7 4814TKK200A SHIELD INVERTER LB782F 8 3313TL7004
