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LG L1918S Service Manual Download Page 17

 

17 

 

TROUBLESHOOTING GUIDE 

 

 

 

 

 

 

 

 

 

 

 

 

 

No Power 

(Power Indicator Off) 

Please reinsert and 
make sure the AC of 
100-240 is normal 

Measure Q702 
Vout=1.8V U701 
PIN2=3.3V 

Check the Adapter/Inverter 
section 

Check CN701 or replace 
Q702, U701 

NO 

NO 

YES 

YES 

1. NO POWER

 

Check X401 oscillate 
waveforms are normal 

Replace U401 

 

Replace X401 

 

NO 

YES 

Summary of Contents for L1918S

Page 1: ...LOR MONITOR SERVICE MANUAL MODEL L1918S L1918S BNQ SNQ A MQP for LPL TLB2 A SQP for HSD A01 A RQP for HSD D10 A OQP for LPL TLL1 TLL3 Sales Market CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL To apply the MSTAR Chip ...

Page 2: ...3 3 Operating Frequency Horizontal 30 83kHz Vertical 56 75Hz 4 Max Resolution D sub Analog 1280 x 1024 75Hz 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 20 80 Non condensing 6 3 MTBF 50 000 HRS with 90 Confidence Lamp Life 50 000 Hours Min 7 DIMENSIONS with TILT SWIVEL Width 418 mm ...

Page 3: ... 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 within the module If the surface of panel become dirty pl...

Page 4: ...st receiver ground lead to the receiver chassis ground before connecting the test 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 ...

Page 5: ...tip as the solder melts 2 Draw away the melted solder with an 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 coati...

Page 6: ...onnection 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 technique involves the installation of a jumper wire on t...

Page 7: ...els 57 283 49 725 1152 832 32 64 224 832 x 624 V Lines 74 55 667 624 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 5 60 023 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 9...

Page 8: ...il Click After then pull down the stand 2 Push the hinge cover as arrow direction 3 Disassemble the hinge cover as arrow direction 4 Remove the four screws 5 Disassemble the bezel from the bottom with a thin card There are two clips on the button 6 Disassembly Back Cover ...

Page 9: ...9 7 Disassemble connector ...

Page 10: ... Pull the Base 2 ea Latches to inside until losing elasticity 2 Consequently pull the stand body directly 3 Separate Stand Body Stand Base 4 Fix Stand Base Stand Body 5 Remove the three screws 6 Separate the hinge and stand ...

Page 11: ...11 BLOCK DIAGRAM ...

Page 12: ...it Switching circuit PWM control IC MOSFER OVP protect circuit Diode rectifier Starting resistor 12V Rush prevention ON OFF DIM Push pull circuit Transformer conversion LC resonance VDDA ON OFF circuit PWM IC OZ9938GN Feedback circuit OVP circuit 4 CCFL lamps Sampling Lamp open protection DIM circuit 12V 5V 100 240V ...

Page 13: ...signal and outputs 8 bit R G B signal to transmitter 2 Power 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 DC 12V to AC 700Vrms and operates ba...

Page 14: ...ergy 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 protection is also monitor by this part 5 Photo Coupler isolation This p...

Page 15: ... is available for LCD Monitor only 1 Port Setup a Copy UserPort 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 ...

Page 16: ...ally sets the gain and offset value c AGING Select Aging mode on off d PANEL used panel type e NVRAM INIT EEPROM initialize 24C08 f R G B 9300K Allows you to set the R G B 9300K value manually g R G B 6500K Allows you to set the R G B 6500K value manually h R G B Offset Allows you to set the R G B Offset value manually Analog Only i R G B Gain Allows you to set the R G B Gain value manually Analog...

Page 17: ...se reinsert and make sure the AC of 100 240 is normal Measure Q702 Vout 1 8V U701 PIN2 3 3V Check the Adapter Inverter section Check CN701 or replace Q702 U701 NO NO YES YES 1 NO POWER Check X401 oscillate waveforms are normal Replace U401 Replace X401 NO YES ...

Page 18: ... 1 3 3V Check U701 PIN 3 5V Check power board and find out a short point as penning each power line 1 Check U701 2 Check C712 714 CHECK D701 1 8V 1 CHECK Q702 2 CHECK D701 D702 3 TROUBLE IN SCALER IC Check CN701 PIN1 5V 1 Check BL ON OFF pulse as contacting scope NO NO NO NO YES YES YES YES ...

Page 19: ...heck C421 C423 2 Check X401 3 TROUBLE IN SCALER IC SCALER PIN96 97 OSCILLATES AS 14 318MHZ No Raster OSD Is Not Displayed SCALER IC PIN27 H SYNC PIN28 V SYNC CHECK CONNECTION LINE FROM D SUB TO SCALER TROUBLE IN CABLE OR LCD MODULE NO YES YES NO ...

Page 20: ...20 4 TROUBLE IN DPM TROUBLE IN DPM SCALER IC PIN27 H SYNC PIN28 V SYNC CHECK H V SYNC LINE TROUBLE IN CABLE OR LCD MODULE NO YES ...

Page 21: ...voltage of C905 Check start voltage for the pin3 of IC901 The auxiliary voltage IC901 pin 7 is between 10V 16V jumping Check AC line Check F901 BD901 Check R906 R907 IC901 Check D902 D902 C907 1 Check IC901 T901 2 Check Q903 ZD903 ZD904 3 Check IC902 IC903 NO YES YES NO YES NO YES NO ...

Page 22: ...th wave at short time Check Q805 Q806 pin5 pin8 is 12V Check PT801 PT802 pin7 pin8 650V Check power section Check Interface section or main board Check Q801 Q802 Q803 ZD801 Check IC801 pin 5 pin6 Cut all the pin connector of Q805 Q806 check C811 12V Unplug backlight connector wire check PT801 PT802 pin7 pin8 650V Check Q801 Q802 Replace PT801 PT802 Replace backlight NO NO NO NO NO YES YES YES ...

Page 23: ...23 WIRING DIAGRAM 95G8014 8D679 89G179J30H 8 or 89G179S30H 8 95G8014 3 28 95G8014 6D643 ...

Page 24: ... 24 EXPLODED VIEW 170 010 020 140 110 040 130 030 120 050 060 080 070 090 100 160 150 190 180 ...

Page 25: ...CORD BLK 6FT For USA Mexico Panama Canada 89G410A 18N IS 6410TBW004A PWR CORD 10A 250V BLK 6FT UK for UK Malaysia 89G420A 18N IS 6410TTW001A PWR CORD BLK 6ft For Taiwan 89G412A 18N IS3 6410TSW003A PWR CORD BLK 6ft For Australia 120 PTPC6AA1 EBU36839301 LED BOARD 130 KEPC6AAB EBU36839101 KEY BOARD 140 PWPC942LL1P EBU36838201 POWER BOARD for LPL PWPC942HL1P EBU36848401 POWER BOARD for HSD 150 CBPC6G...

Page 26: ...R 16V 100N P C422 065G0603104 12 CER2 0603 X7R 16V 100N P C444 065G0603104 12 CER2 0603 X7R 16V 100N P C445 065G0603104 12 CER2 0603 X7R 16V 100N P C709 065G0603104 12 CER2 0603 X7R 16V 100N P C713 065G0603104 12 CER2 0603 X7R 16V 100N P C714 065G0603104 12 CER2 0603 X7R 16V 100N P C715 065G0603104 12 CER2 0603 X7R 16V 100N P C718 065G0603104 12 CER2 0603 X7R 16V 100N P C419 065G0603104 12 CER2 06...

Page 27: ...47UF 50V X7R C437 065G0603473 32 CHIP 0 047UF 50V X7R C436 065G0603473 32 CHIP 0 047UF 50V X7R C434 065G0603473 32 CHIP 0 047UF 50V X7R C433 065G0603473 32 CHIP 0 047UF 50V X7R C432 065G0603473 32 CHIP 0 047UF 50V X7R DIODEs D415 093G 39147 TZMC5V6 D413 093G 39147 TZMC5V6 D412 093G 39147 TZMC5V6 D411 093G 39147 TZMC5V6 D410 093G 39147 TZMC5V6 D409 093G 39147 TZMC5V6 D408 093G 39147 TZMC5V6 D406 09...

Page 28: ...PMBS3906 PHILIPS SMT 06 Q402 057G 417 12 T KEC 2N3904S RTK PS Q703 057G 417 12 T KEC 2N3904S RTK PS Q706 057G 417 13 T KEC 2N3906S RTK PS Q403 057G 417 13 T KEC 2N3906S RTK PS Q401 057G 417 13 T KEC 2N3906S RTK PS Q702 057G 417 17 T PZT2907A Q702 057G 41717B T tra PZT2907A PHILIPS Q704 057G 763 1 A03401 SOT23 BY AOS A1 Q704 057G 763 1A AP2305N RESISTORs R706 061G0603000 RST CHIPR 0 OHM 5 1 10W R72...

Page 29: ... KOHM 5 1 10W R701 061G0603103 RST CHIPR 10 KOHM 5 1 10W R404 061G0603103 RST CHIPR 10 KOHM 5 1 10W R406 061G0603103 RST CHIPR 10 KOHM 5 1 10W R408 061G0603103 RST CHIPR 10 KOHM 5 1 10W R413 061G0603103 RST CHIPR 10 KOHM 5 1 10W R415 061G0603103 RST CHIPR 10 KOHM 5 1 10W R416 061G0603103 RST CHIPR 10 KOHM 5 1 10W R424 061G0603103 RST CHIPR 10 KOHM 5 1 10W R425 061G0603103 RST CHIPR 10 KOHM 5 1 10W...

Page 30: ...0805 FB402 071G 56Z601 CHIP BEAD 600 OHM 0805 FB403 071G 56Z601 CHIP BEAD 600 OHM 0805 FB404 071G 56Z601 CHIP BEAD 600 OHM 0805 FB405 071G 56Z601 CHIP BEAD 600 OHM 0805 FB406 071G 56Z601 CHIP BEAD 600 OHM 0805 FB409 071G 59B121 TB160808B FB412 071G 59K300 B CHIP BEAD FCB1608KF 300T07 bullwill FB411 071G 59K300 B CHIP BEAD FCB1608KF 300T07 bullwill FB410 071G 59K300 B CHIP BEAD FCB1608KF 300T07 bul...

Page 31: ...0V X7R C908 065G0805104 32 CHIP 0 1U 50V X7R C904 065G0805104 32 CHIP 0 1U 50V X7R C832 065G0805104 32 CHIP 0 1U 50V X7R C829 065G0805104 32 CHIP 0 1U 50V X7R C828 065G0805104 32 CHIP 0 1U 50V X7R C822 065G0805104 32 CHIP 0 1U 50V X7R C821 065G0805104 32 CHIP 0 1U 50V X7R C817 065G0805104 32 CHIP 0 1U 50V X7R C802 065G0805104 32 CHIP 0 1U 50V X7R C801 065G0805104 32 CHIP 0 1U 50V X7R C830 065G0805...

Page 32: ...64 33 DIO SIG SM BAV99 PHSE R D801 093G 64 33 DIO SIG SM BAV99 PHSE R D904 093G 6432S IN4148W D807 093G 6432S IN4148W D808 093G 6432S IN4148W D809 093G 6432S IN4148W D810 093G 6432S IN4148W D811 093G 6432S IN4148W ZD801 093G 39S 24 T RLZ 5 6B LLDS ZD902 093G 39S 24 T RLZ 5 6B LLDS ZD903 093G 39S 38 T PTZ 9 1B ZD901 093G 39S 40 T RLZ 13B LLDS ZD906 093G 39S 42 T RLZ27B LLDS ZD904 093G 39S 44 T RLZ1...

Page 33: ...4 AM9945N Q806 057G 763 14 AM9945N Q801 057G 417 12 T KEC 2N3904S RTK PS Q802 057G 417 12 T KEC 2N3904S RTK PS Q803 057G 417 12 T KEC 2N3904S RTK PS Q805 057G 763 6 AO4828L Q806 057G 763 6 AO4828L Q903 006G 31502 1 5MM RIVET RESISTORs R905 061G152M10458F 100K OHM 5 2W R914 061G152M43858F RST MOFR 0 43OHM 5 2WS NR901 061G 58005 W RST NTCR 5 OHM 3A THINKING JR801 061G0805000 0 OHM 1 10W JR821 061G08...

Page 34: ...51 KOHM 5 1 8W R917 061G0805683 68K 8 1 10W R824 061G0805751 RST CHIPR 750 OHM 5 1 8W R858 061G0805751 RST CHIPR 750 OHM 5 1 8W R827 061G0805752 RST CHIPR 7 5 KOHM 5 1 8W R831 061G0805752 RST CHIPR 7 5 KOHM 5 1 8W R814 061G0805754 RST CHIPR 750 KOHM 5 1 8W R823 061G0805823 RST CHIPR 82 KOHM 5 1 8W R830 061G0805823 RST CHIPR 82 KOHM 5 1 8W JR904 061G1206000 0 OHM 1 8W JR903 061G1206000 0 OHM 1 8W J...

Page 35: ... RST CHIPR 680 KOHM 5 1 4W R903 061G1206684 RST CHIPR 680 KOHM 5 1 4W NR901 006G 31502 1 5MM RIVET R822 061G212Y625 KT MGFR 6 2MOHM 5 1 2W R832 061G212Y625 KT MGFR 6 2MOHM 5 1 2W TRANSFORMER PT801 080GL19T 8DN1 X FMR DARFONTK 2006M 101 PT802 080GL19T 8DN1 X FMR DARFONTK 2006M 101 T901 080GL19T 25 L X FMR 550uH PT 0076563 3 T901 080GL19T 25 YS X FMR 550uH YS04160073 PT802 S80GL19T8V1 TRANSFORMER AS...

Page 36: ...36 L902 S73L17455VG TRANSFORMER ASS Y L901 006G 31502 1 5MM RIVET L902 006G 31502 1 5MM RIVET F901 084G 33 10 FUSE CLIP F901 084G 41 3 3 15AH 250V FB901 071G 55 29 FERRITE BEAD ...

Page 37: ...SCHEMATIC B5 5 PANEL INTERFACE VLCD B 0 9 A 0 9 VLCD 5V B4 4 SCALER RIN GIN SOG BIN GNDR GNDG GNDB HSYNC VSYNC Adj_BACKLIGHT VCC1 8 Vcc3 3 VCTRL A 0 9 B 0 9 DDCA_SDA DDCA_SCL DET_VGA on_BACKLIGHT on_Panel 5V DDC_WP VCC1 8 VCC1 8 B 0 0 PC5V B2 2 POWER on_Panel on_BACKLIGHT Adj_BACKLIGHT VCC1 8 VLCD 5V VCTRL VCC5V VCC3 3 PC5V LVDS OUTPUT VCC3 3 5V VCC5V 1 SCALER ...

Page 38: ...L_ADJ C718 0 1uF 16V 47 R728 150Ω 1 10W 5V 5V Q701 NC 5V 3 4 U702 U701 TO 263 C712 10uF 16V R727 10KΩ 1 10W X VCC3 3 C709 0 1uF 16V R723 51 KOHM 5 1 10W on_BACKLIGHT 4 0V 3 3V 1UF C702 4 7uF VCC3 3 3 4 C711 NC 5V VCC5V C708 X R711 10KΩ 1 10W 5V C714 0 1uF 16V 1UF 5V 3 4 4K7 X R714 10KΩ 1 10W R701 Q701 R705 R702 51Ω 1 10W C708 R717 10KΩ 1 10W BL_ADJ 5V R712 4 7KΩ 1 10W R708 10KΩ 1 10W N C R701 10KΩ...

Page 39: ...MM5V6 5V 2 4 C438 0 047uF50V RIN 4 VSYNC 4 PC5V R441 100Ω 1 10W R436 56Ω 1 10W PC5V R438 75 OHM 1 1 10W U404 M24C02 RMN6TP 1 2 3 4 5 6 7 8 A0 A1 A2 VSS SDA SCL WP VCC BIN 4 DDCA_SDA 4 R444 10KΩ 1 10W D404 BAV99 3 1 2 D407 BAV70 3 1 2 5V RED C447 NC R439 75 OHM 1 1 10W C433 0 047uF50V FB411 30 OHM 1 2 R454 100Ω 1 10W R447 1KΩ 1 10W R449 2 2KΩ 1 10W GIN 4 VCC3 3 FB410 30 OHM 1 2 GREEN D412 ZMM5V6 VS...

Page 40: ... 3 MENU LEDA R417 NC R404 10KΩ 1 10W R406 10KΩ 1 10W on_PANEL 2 RIN 3 A6 FB401 600 OHM GNDR 3 DDC_WP 3 adj_BACKLIGHT 2 R483 10KΩ 1 10W VCC1 8 GNDG 3 B5 RIGHT VCC3 3 SPI_WP R409 100Ω 1 10W KEY_POWER R410 NC POWER VCC3 3 VMPLL R408 10KΩ 1 10W B 0 9 5 B 0 9 FB403 600 OHM R419 47Ω 1 10W C408 10uF 16V C426 330pF KEY_MENU 23 20 21 18 22 19 17 27 28 15 26 25 37 39 38 40 47 86 59 96 97 60 61 62 63 64 65 6...

Page 41: ...VB2M LVBCKM LVACKP LVA2M LVB2M CN102 CONN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 B1 LVB1M B 0 9 LVA0P A8 A1 LVA3P LVA0M LVA3M LVA3P B5 LVBCKP LVB0P LVA1P LVA1M LVA2P VLCD LVB3P LVA3M LVBCKM B0 A7 B 0 9 4 B7 A3 A 0 9 A2 B6 LVB2P LVA3M LVBCKP LVB0M B9 B2 A4 LVB0M B3 A5 LVB0P LVA0P A0 ...

Page 42: ...35 4 7 K 1 4W ON OFF 61G0805751 PT801 POWER X FMR 5 3 7 4 1 8 61G212Y625 KT Q804 RK7002 C817 0 1uF 0805 61G0805473 C808 180 K1 8W Q810 RK7002 65G0805104 32 R803 10KΩ 1 8W R807 22 1 4W 93G 6432S 57G 759 2 65G0805222 31 D804 BAV99 3 1 2 65G 3J3096ET Q802 PMBS3904 67G215L471 4H R808 47KΩ 1 8W D803 BAV99 3 1 2 D805 BAV99 3 1 2 61G1206472 61G1206472 61G1206220 61G0805102 Q808 RK7002 R831 7 5 K 1 8W 93G...

Page 43: ...61G1206151 D904 1N4148W 61G1206103 C903 0 47uF 275V R917 68KΩ 1 8W 61G1206154 IC903 AZ431AZ AE1 65G0805104 32 BD901 GBU408 2 1 3 4 R914 0 43 2W C930 0 0015uF 2KV 5V 93G 39S 40 T 65G 2K152 1T GP R905 100KΩ 2W C919 0 1uF D907 SP10150 1 2 3 57G 667516 C904 0 1uF R910 10Ω 1 4W 71G 55 29 061G0805330 2F 56G 139 3A 61G0805103 T901 6 9 5 4 2 1 7 3 10 8 R919 150 1 4W R901 680KΩ L901 73L 174 53 LG GP 1 4 2 ...

Page 44: ...Jan 2007 P NO MFL36713631 Printed in China ...

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