LG L1942HE Service Manual Download Page 1

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COLOR MONITOR

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE UNIT,

READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

CHASSIS NO. : LM72A

MODEL:

L1942H

(L1942H

-BFT.A***

PN)

*To apply the MSTAR Chip .

(

) **Same model for Service

Website:http://biz.LGservice.com

Internal Use Only

AUTO/SET

VOLUME

Summary of Contents for L1942HE

Page 1: ...ION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL CHASSIS NO LM72A MODEL L1942H E L1942HE BFT A OPN To apply the MSTAR Chip Same model for Service Website http biz LGservice com Internal Use Only AUTO SET VOLUME ...

Page 2: ... 75Hz Digital 1280 x 1024 60Hz 5 POWER SUPPLY 5 1 Power AC 100 240V 50 60Hz 0 8A 5 2 Power Consumption 6 ENVIRONMENT 6 1 Operating Temperature 10 C 35 C 50 F 95 F Ambient 6 2 Relative Humidity 10 80 Non condensing 6 3 MTBF 50 000 HRS with 90 Confidence Lamp Life 50 000 Hours Min 7 DIMENSIONS with TILT SWIVEL Width 406 3 mm 16 00 Depth 237 5 mm 9 35 109 8 mm 4 32 Height 463 7 mm 18 26 358 0 mm 14 0...

Page 3: ...s pencil or pen as this may result in damage to the panel Protect the module from the ESD as it may damage the electronic circuit C MOS Make certain that treatment person s body are grounded through wrist band Do not leave the module in high temperature and in areas of high humidity for a long time The module not be exposed to the direct sunlight Avoid contact with water as it may a short circuit ...

Page 4: ...receiver positive lead Always remove the test receiver ground lead last 9 Use with this receiver only the test fixtures specified in this service manual CAUTION Do not connect the test fixture ground strap to any heat sink in this receiver Electrostatically Sensitive ES Devices Some semiconductor solid state devices can be damaged easily by static electricity Such components commonly are called El...

Page 5: ...n anti static suction type solder removal device or with solder braid before removing the IC Replacement 1 Carefully insert the replacement IC in the circuit board 2 Carefully bend each IC lead against the circuit foil pad and solder it 3 Clean the soldered areas with a small wire bristle brush It is not necessary to reapply acrylic coating to the areas Small Signal Discrete Transistor Removal Rep...

Page 6: ... and carefully crimp it around the IC pin Solder the IC connection 4 Route the jumper wire along the path of the out away copper pattern and let it overlap the previously scraped end of the good copper pattern Solder the overlapped area and clip off any excess jumper wire At Other Connections Use the following technique to repair the defective copper pattern at connections other than IC Pins This ...

Page 7: ... 667 624 1 3 39 8 H Pixels 65 0 48 363 1344 1024 24 136 160 1024 x 768 V Lines 60 0 806 768 3 6 29 9 H Pixels 78 75 60 123 1312 1024 16 96 176 1024 x 768 V Lines 75 029 800 768 1 3 28 10 H Pixels 100 0 68 681 1456 1152 32 128 144 1152 x 870 V Lines 75 062 915 870 3 3 39 11 H Pixels 92 978 61 805 1504 1152 18 134 200 1152 x 900 V Lines 65 96 937 900 2 4 31 12 H Pixels 108 0 63 981 1688 1280 48 112 ...

Page 8: ...ronics Inc All right reserved Only for training and service purposes DISASSEMBLY Disassemble Hinge cover Remove the screws 1 2 4 5 1 Pull the front cover upward Disassemble back cove 2 Then let the all latches are separated 3 Put the front face down ...

Page 9: ...ter 5V 12V 5V 3 3V 1 8V Vcc 5V 5V Scaler MCU Intel8032 Inverter 4 lamps 12V Regulator KEY 3 3V 1 8V Line Buffer OSD SSC EEPROM System Module 3 3V SDA SCL 3 3V Flash ROM 12V EEPROM EDID 9 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only ...

Page 10: ...ternal Use Only LAMP High Low POWER INVERTER Inverter Control IC P ch N ch Inverter Trans SMPS Lamp Current Feedback Over Voltage Protection Power Control IC Feedback Line Filter L N Drive Block 15V 13V 5V Inverter On OFF 3 3V Dimming Lamp Current Control Aux Drive Start Module Vcc Main Board Scaler DC DC converter 15V 5V ...

Page 11: ...er Part This part consists of the one 3 3V and one 1 8V regulators to convert power which is provided 5V in Power board 12V is provided for inverter 5V is provided for LCD panel Also 5V is converted 3 3V and 1 8V by regulator Converted power is provided for IC in the main board The inverter converts from DC12V to AC 700Vrms and operates back light lamps of module 3 MICOM Part This part is include ...

Page 12: ... Energy Transfer This part function is for transfer the primary energy to secondary through a power transformer 4 Output rectifier and filter This part function is to make a pulse width modulation control and to provide the driver signal to power switch to adjust the duty cycle during different AC input and output loading condition to achieve the dc output stabilized and also the over power protec...

Page 13: ...rt sys file to c WINNT system32 drivers folder b Run Userport exe c Remove all default number d Add 300 3FF e Click Start button f Click Exit button 2 EDID Read Write 1 Run WinEDID exe 2 Edit Week of Manufacture Year of Manufacture Serial Number a Input User Info Data b Click Update button c Click Write button 13 Copyright 2007 LG Electronics Inc All right reserved Only for training and service pu...

Page 14: ...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 b NVRAM INIT EEPROM initialize 24C08 c CLEAR ETI To initialize using time d AGING Select Aging m...

Page 15: ...01 96 Check Key Control Connector Routine Check U501 NO NO Check 3 3V Line Open Check Check 3 3V Line NO Check X TAL YES Check J703 Voltage Pin5 Pin6 5V Check U601 Pin2 Voltage 3 3V Is U501 Pin75 3 3V Voltage Check U501 Pin 96 Pulse 1 YES YES YES 15 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only ...

Page 16: ...HECK MICOM INV ON OFF PORT 1 CONFIRM BRIGHTNESS OSD CONTRL STATE 2 CHECK MICOM DIM ADJ PORT LIPS J703 PIN5 PIN6 5V J703 PIN9 5V J703 PIN10 5V CHECK PULSE AS CONTACTING SCOPE PROBE TO CAUTION LABEL CONTACT PROBE TO CAUTION LABEL CAN YOU SEE PULSE AT YOUR SCOPE YES YES YES YES 16 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only ...

Page 17: ...N U201 CHECK CONNECTION LINE FROM D SUB TO U201 U201 PIN96 97 OSCILLATE AS 14 31MHZ U201 PIN27 IS 48KHz H SYNC PIN28 IS 60Hz V SYNC IS PULSE APPEARED AT SIGNAL PINS AT MODE 12 1 2 1 2 Waveforms U201 96 97 U201 27 H SYNC 2 U201 28 V SYNC YES YES YES U201 PIN 16 75 3 3V 17 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only ...

Page 18: ...PC IS NOT GOING INTO DPM OFF MODE CHECK H V SYNC LINE CHECK R730 R731 CHECK U201 PIN 27 28 SYNC PULSE 3 3 Waveforms R730 H Syn 3 R731V Sync YES YES 18 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only ...

Page 19: ...OR OFF NO Trouble in Fuse F101 CHECK 5V 15V Line NO NO Check D104 D105 D106 D107 Check U101 Pin7 9 10V Check D102 Trouble in Q101 NO Trouble in D201 D202 D203 YES CHECK Fuse F101 OK CHECK C101 Voltage AC110V 160Vdc AC220V 304Vdc CHECK U101 Pin6 Waveform Square wave Come out Check Q101 Drain Waveform Check D201 D202 D203 Voltage YES YES YES YES NO ...

Page 20: ...Scaler Output Main Board CHECK T301 NO NO Check Q301 Q302 Check the waveform of U301 Pin1 15 Check the waveform of U301 Pin2 3 NO If waveform is no problem Check D302 D308 Or Trouble in U303 U304 YES CHECK P201 Pin9 3 3V Check U301 Pin2 5V Check U301 Pin6 VSEN Less than 3V Check U301 Pin12 SSTCMT Less than 1V Check U303 U304 Drain waveform YES YES YES NO ...

Page 22: ...300 320 310 420 400 200 330 520 510 410 970 900 910 920 930 940 950 960 430 440 ...

Page 27: ...MAR 2010 P NO MFL40349781 Printed in China ...

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