Page 1
Website:http://biz.LGservice.com COLOR MONITOR SERVICE MANUAL CHASSIS NO. : LM57B MODEL: L1953H (L1953H-BFQ.A**MQP) ) **Same model for Service CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. *To apply the MSTAR Chip.
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...
SERVICING PRECAUTIONS CAUTION: Before servicing receivers covered by this 9. Use with this receiver only the test fixtures specified in service manual and its supplements and addenda, read this service manual. and follow the SAFETY PRECAUTIONS on page 3 of this CAUTION: Do not connect the test fixture ground strap publication.
Page 5
General Soldering Guidelines Replacement 1. Use a grounded-tip, low-wattage soldering iron and 1. Carefully insert the replacement IC in the circuit board. appropriate tip size and shape that will maintain tip 2. Carefully bend each IC lead against the circuit foil pad and solder it.
Page 6
Circuit Board Foil Repair At Other Connections Excessive heat applied to the copper foil of any printed Use the following technique to repair the defective copper circuit board will weaken the adhesive that bonds the foil pattern at connections other than IC Pins. This technique to the circuit board causing the foil to separate from or involves the installation of a jumper wire on the "lift-off"...
TIMING CHART VIDEO SYNC Total Video Sync Front Blanking Sync MODE H / V Frequency Duration Porch Time Period Active Resolution Polarity Clock ( D ) ( C ) ( B ) ( E ) Time ( A ) H(Pixels) 25.175 31.469 640 x 350...
DISASSEMBLY-Set Hold the product as it follows and lift up the Stand Change your hold on the product as it follows and turn slightly. the Stand Base in the arrow direction until you hear a "click." Pull out the Stand to remove. Remove the screws.
Page 9
DISASSEMBLY-Stand Hold the body of the Stand as it follows. Press the two latches at the same time as it follows. Pushing Latch inside,Take the stand base from stand The body of the Stand and the Stand Base are body. successfully separated.
DESCRIPTION OF BLOCK DIAGRAM 1. Video Controller Part. This part amplifies the level of video signal for the digital conversion and converts 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 135MHz.
LIPS Board Block Diagram 50 ~ 60Hz 100KHz HVDC SWITCHING INPUT RECTIFIER OUTPUT RECTIFIER TRANSFORMER COMPONENTS AND FILTER AND FILTER LINE 100 ~ 240V SIGNAL PWM CONTROL COLLENT- PHOTO-COUPLER CIRCUIT ISOLATION PRIMARY SECONDARY INVERTER CIRCUIT High Voltage Operation description_LIPS 1. EMI components. This part contains of EMI components to comply with global marketing EMI standards like FCC,VCCI CISPR, the circuit included a line-filter, across line capacitor and of course the primary protection fuse.
ADJUSTMENT Windows EDID V1.0 User Manual 2. EDID Read & Write 1) Run WinEDID.exe Operating System: MS Windows 98, 2000, XP Port Setup: Windows 98 => Don’t need setup Windows 2000, XP => Need to Port Setup. This program is available to LCD Monitor only. 1.
SERVICE OSD 1) Turn off the power switch at the front side of the display. 2) Wait for about 5 seconds and press MENU, POWER switch with 1 second interval. 3) The SVC OSD menu contains additional menus that the User OSD menu as described below. a) Auto Color : W/B balance and Automatically sets the gain and offset value.
TROUBLESHOOTING GUIDE 1. NO POWER NO POWER (POWER INDICATOR OFF) CHECK POWER BOARD, CHECK J302 AND FIND OUT A SHORT VOLTAGE POINT AS OPENING PIN5, PIN6 (5V)? EACH POWER LINE CHECK CHECK 3.3V LINE U202 PIN 3 VOLTAGE (OPEN CHECK) (3.3V) ? NO PROBLEM CHECK KEY CONTROL...
Page 17
2. NO RASTER (OSD IS NOT DISPLAYED) – LIPS NO RASTER (OSD IS NOT DISPLAYED) CHECK POWER BOARD, J302 AND FIND OUT A SHORT PIN5, PIN6 POINT AS OPENING EACH POWER LINE CHECK MICOM INV J705 PIN9 ON/OFF PORT. 1. CONFIRM BRIGHTNESS OSD CONTRL STATE.
Page 18
3. NO RASTER (OSD IS NOT DISPLAYED) – MSTAR NO RASTER (OSD IS NOT DISPLAYED) U201 CHECK U202 PIN 16, 76 3.3V? U201 1. CHECK C108, C109 SOLDERING CONDITION PIN96, 97 OSCILLATE AS 2. CHECK X101 14.31MHZ? 3. TROUBLE IN U101 U101 PIN27 IS 48KHz H-SYNC? CHECK CONNECTION...
Page 19
4. TROUBLE IN DPM TROUBLE IN DPM CHECK PC CHECK PC IS NOT GOING R332, R333 INTO DPM OFF MODE CHECK U101 PIN 27,28 CHECK H/V SYNC LINE SYNC PULSE ? TROUBLE IN U101 Waveforms 3 R333 V-Sync R332 H-Sync - 19 -...
Page 20
5. POWER NO POWER (POWER INDICATOR OFF) CHECK Trouble in Fuse (F101) Fuse F101 OK? CHECK C101 Voltage Check BD101 (AC110V->160Vdc (AC220V->304Vdc CHECK Check U101 Pin7 : 9~10V U101 Pin6 Waveform Check D102 (Square wave Come out?) Check Q101 Drain Trouble in Q101 Waveform Check D201, D202...
Page 21
6. Raster NO Raster (Lamp Off) CHECK Check Scaler Output P201 Pin9 (Main Board) 3.3V? Check U301 Pin3 Check Q301, Q302 Check the waveform of U301 Check U301 Pin2 OVP, Pin11, 12, 19, 20 Less than 1.8V Check the waveform of U301 Check U301 Pin10 CMP, Pin11, 12, 19, 20 Less than 2.75V...
REPLACEMENT PARTS LIST CAUTION: BEFORE REPLACING ANY OF THESE COMPONENTS, READ CAREFULLY THE SAFETY PRECAUTIONS IN THIS MANUAL. MAIN BOARD AND POWER BOARD PARTS ARE DIFFERENT. * NOTE SAFETY Mark AL ALTERNATIVE PARTS DATE: 2007. 03. 02. DATE: 2007. 03. 02. *S *AL LOC.