LG Flatron W1941S Service Manual Download Page 18 | Manualshive

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LG Flatron W1941S Service Manual Download Page 18

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TROUBLESHOOTING GUIDE

No Power

(Power Indicator Off)

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

Measure C704 (+)
=1.8V
U701 PIN2=3.3V

Check the Adapter/Inverter
section

Check CN701 or replace
Q702, Q703, and U701

1. NO POWER

Check X401 oscillate
waveforms are normal

Replace U401

http://www.wjel.net

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Summary of Contents for Flatron W1941S

Page 1: ... www LGEservice com techsup html COLOR MONITOR SERVICE MANUAL MODEL W1941S Sales Market CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL To apply the MSTAR Chip h t t p w w w w j e l n e t ...

Page 2: ... Typ 2 2 Luminance 250Cd m2 min 300Cd m2 Typ 6500K 170Cd m2 min 9300K 2 3 Contrast Ratio 600 min 1000 Typ 3 SIGNAL Refer to the Timing Chart 3 1 Sync Signal Type Separate Sync SOG Sync On Green 3 2 Video Input Signal 1 Type R G B Analog 2 Voltage Level 0 0 7 Vp p 3 Input impedance 75 Ω 3 3 Operating Frequency Horizontal 30 61kHz Vertical 56 75Hz 4 Max Resolution D sub Analog VESA 1360 x 768 60 Hz ...

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Page 5: ... 5 h t t p w w w w j e l n e t ...

Page 6: ... 6 h t t p w w w w j e l n e t ...

Page 7: ... 7 TIMING CHART h t t p w w w w j e l n e t ...

Page 8: ...lat 2 Pull out the stand and the hinge cover 3 Remove the three screws 4 Put the front cover upward Then let the all latches are separated 5 Put the front face down disassembly back cover 6 Pull the key board out of bezel h t t p w w w w j e l n e t ...

Page 9: ... 9 7 Disassembly the bezel 8 Disassembly the connector and screw 9 Remove the screw 10 Disassemble the FFC cable 11 Main board and power board 12 The panel h t t p w w w w j e l n e t ...

Page 10: ... 1 Pull the Base 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 Separate the hinge and stand h t t p w w w w j e l n e t ...

Page 11: ... 11 BLOCK DIAGRAM h t t p w w w w j e l n e t ...

Page 12: ...ircuit 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 2 CCFL lamps Sampling Lamp open protection DIM circuit 12V 5V 100 240V h t t p w w w w j e l n e t ...

Page 13: ...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 back light la...

Page 14: ...ary 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 part function i...

Page 15: ...he signal line of monitor with DDC recorder 2 Choose the DDC RECORD program and it shows on the screen the choose the correct source base on the monitor 3 Click LoadFile then key in the manufacturer name model name product code then choose the correct model name base on the monitor as Fig 2 4 Scan serial No to DDC recorder by Bar Reader then read again in the Verify SN 5 According to the message o...

Page 16: ...heck sum It must be the same as the last byte of data table as follows picture shows Above of all must be right then if it shows the green PASS it means record succeeds the red Fail means record fails then check the power supply and signal line and ensure they are connected well then do DDC record again from the third step Fig 2 h t t p w w w w j e l n e t ...

Page 17: ... gain and offset value c AGING Select Aging mode on off d PANEL used panel type e NVRAM INIT EEPROM initialize 24C04 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 Only Figure ...

Page 18: ...make sure the AC of 100 240v is normal Measure C704 1 8V U701 PIN2 3 3V Check the Adapter Inverter section Check CN701 or replace Q702 Q703 and U701 NO NO YES YES 1 NO POWER Check X401 oscillate waveforms are normal Replace X401 Replace U401 NO YES h t t p w w w w j e l n e t ...

Page 19: ...01 PIN 3 5V Check power board and find out a short point as penning each power line 1 Check U701 2 Check C706 C707 Check C704 1 8V 1 Check Q702 Q703 2 CheckC704 C705 3 TROUBLE IN SCALER IC NO NO NO YES YES YES Check CN701 PIN 3 5V YES NO Check BL ON OFF pulse as contacting scope h t t p w w w w j e l n e t ...

Page 20: ...2 Check X401 3 TROUBLE IN SCALER IC SCALER PIN 96 97 OSCILLATES AS 14 318MHZ No Raster OSD Is Not Displayed CHECK CONNECTION LINE FROM D SUB TO SCALER TROUBLE IN CABLE OR LCD MODULE NO YES YES NO SCALER IC PIN 27 H SYNC PIN 28 V SYNC h t t p w w w w j e l n e t ...

Page 21: ... 21 4 TROUBLE IN DPM TROUBLE IN DPM SCALER IC PIN 27 H SYNC PIN 28 V SYNC CHECK H V SYNC LINE TROUBLE IN CABLE OR LCD MODULE NO YES h t t p w w w w j e l n e t ...

Page 22: ...tage for the pin1 of IC901 Check IC901 pin 7 Vcc is 13v Check AC line Check F901 BD901 Check D905 R934 R929 R928 IC901 Check D902 C907 Check IC901 T901 D907 D908 ZD903 ZD902 ZD901 IC902 IC903 NO YES YES NO YES NO YES NO Check IC901 PIN6 output is PWM Check D901 Q903 ZD904 NO h t t p w w w w j e l n e t ...

Page 23: ...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 Replace PT801 PT802 NO NO NO NO NO YES YES YES Check IC801 Pin1 pin15 have the output of sawtooth Check PT801 PT802 pin7 pin8 650V Replace Q805 Q806 Check Q801 Q802 Replace backlight Replace IC801 NO YES NO YES YES NO YES NO h t t p w w w w j e l n e t...

Page 24: ... 24 WIRING DIAGRAM 95G820H 6W503 089G179J30N511 95G 825 7D504 h t t p w w w w j e l n e t ...

Page 25: ... 25 EXPLODED VIEW h t t p w w w w j e l n e t ...

Page 26: ...21CYA1 POWER BOARD 070 756GQ8CB KL005 MAIN BOARD CBPCRM5LMQ2 080 Q15G0360101 MAINFRAME 090 Q34G0460 B6 1B0100 REAR COVER 18 5 100 Q37G0104012 HINGE 110 Q34G0462 B6 1B0100 STAND TOP 120 Q34G0463 B6 1B0100 HINGE COVER 130 Q34G0464 B6 1B0132 STAND 140 Q34G0465 B6 1B0133 BASE 2 150 Q33G0240 B6 1L0100 RELEASE BUTTON 160 Q12G6600 6 FOOT 170 089G179J30N511 FFC CABLE 180 089G 728HAA 2G SIGNAL CABLE 190 08...

Page 27: ...CER 0 22UF 20 80 C402 067G 3151007KB EC 10UF M 50V 5 11 C403 065G0402104 15 MLCC 0402 0 1UF K 16V X5R C404 065G0402104 15 MLCC 0402 0 1UF K 16V X5R C405 065G0402104 15 MLCC 0402 0 1UF K 16V X5R C406 065G0402104 15 MLCC 0402 0 1UF K 16V X5R C407 065G0402104 15 MLCC 0402 0 1UF K 16V X5R C408 065G0402104 15 MLCC 0402 0 1UF K 16V X5R C409 065G0402104 15 MLCC 0402 0 1UF K 16V X5R C410 065G0402104 15 ML...

Page 28: ... AZC099 04S SOT23 6L U104 056G 662 13 IC AZC099 04S SOT23 6L U401 056G 562208 IC TSUM1PFL LF PQFP 100 SMTCR U402 100GKMG8000N11 MCU ASS Y 056G1133 81 U403 056G1133 32 IC M24C04 WMN6TP SO8 U701 056G 585 4A IC AP1117E33L 13 TRANSISTOR Q301 057G 763 1 A03401 SOT23 BY AOS A1 Q302 057G 417517 LMBT3906LT1G SOT 23 BY LRC Q406 057G 763 1 A03401 SOT23 BY AOS A1 Q701 057G 417518 LMBT3904LT1G SOT 23 BY LRC Q...

Page 29: ... RST CHIPR 10 KOHM 5 1 16W R415 061G0402101 RST CHIPR 100 OHM 5 1 16W R416 061G0402101 RST CHIPR 100 OHM 5 1 16W R417 061G0402101 RST CHIPR 100 OHM 5 1 16W R419 061G0402000 RST CHIP MAX 0R05 1 16W R420 061G0402121 RST CHIP 120R 1 16W 5 R421 061G0402104 RST CHIPR 100 KOHM 5 1 16W R423 061G0402000 RST CHIP MAX 0R05 1 16W R428 061G0402101 RST CHIPR 100 OHM 5 1 16W R429 061G0402101 RST CHIPR 100 OHM 5...

Page 30: ...HM 5 1 8W C809 065G0805473 32 CHIP 0 047UF 50V X7R C810 065G080556131G MLCC 0805 560PF G 50V NPO C811 067G215P4714AV CAP 105 470UF M 25V C813 065G0805102 31 CAP CHIP 0805 1000PF J 50V NPO C814 065G0805105 22 CAP CHIP 0805 1UF K 25V X7R C819 065G0805473 32 CHIP 0 047UF 50V X7R C820 065G0805472 32 CAP CHIP 0805 4700PF K 50V X7R C822 065G0805104 32 CAP CHIP 0805 0 1UF K 50V X7R C825 065G 6J1206ET 12P...

Page 31: ...C922 067G215D4713KT 105 EC 470UF M 16V KINGNICHI C923 067G 2046812KT CS CAP 680UF 10V 8 11 MM C925 067G215S10915T3964 EC CAP 1 0UF 450V 8 11MM C930 065G 2K222 2T6921 CAP CER 2200PF K 2KV Y5P C931 065G 2K152 1T GP CERAMIC CAP C932 065G0603102 32 1000PF 10 50V X7R C934 065G 2K152 1T GP CERAMIC CAP DIODE BD901 093G 50460 38 BRIDGE KBJ408G 4A 800V KBJ BD901 006G 31500 EYELET D801 093G 64 33 DIO SIG SM...

Page 32: ...8B LLDS ZD906 093G 39S 42 T RLZ27B LLDS TRANSISTOR IC IC801 056G 608 10 IC OZ9938GN B SOIC 16 IC901 056G 379 79 IC LD7522PS SOP 8 IC902 056G 139 7 1 IC EL817MA M TYPE IC902 056G 139 3A IC PC123Y22FZ0F IC903 056G 158 7 AP431V TO 92BY ATC IC903 056G 158 10 T IC AS431AZTR E1 TO 92 IC903 056G 158 12 KIA431A AT P TO 92 Q801 057G 417 12 T KEC 2N3904S RTK PS Q802 057G 417 12 T KEC 2N3904S RTK PS Q803 057...

Page 33: ...ST CHIPR 5 1 OHM 5 1 4W R840 061G0805105 RST CHIPR 1M OHM 5 1 8W R841 061G0805430 0F RST CHIPR 430 OHM 1 1 8W R842 061G1206519 RST CHIPR 5 1 OHM 5 1 4W R844 061G0805105 RST CHIPR 1M OHM 5 1 8W R846 061G0805511 RST CHIPR 510 OHM 5 1 8W R847 061G0805105 RST CHIPR 1M OHM 5 1 8W R858 061G0805751 RST CHIPR 750 OHM 5 1 8W R901 061G1206684 RST CHIPR 680K OHM 5 1 4W R902 061G1206684 RST CHIPR 680K OHM 5 1...

Page 34: ...R 250 OHM 5 2WS R936 061G0805471 RST CHIPR 470 OHM 5 1 8W R937 061G0805102 RST CHIPR 1K OHM 5 1 8W TRANSFORMER PT801 080GL22T 1 H XFMR INVERTER 86 7UH DADON PT801 006G 31502 1 5MM RIVET T901 006G 31502 1 5MM RIVET T901 S80GL22T2V TRANSFORMER SUBASSEMBLY OTHER CN801 033G8021 2E F WAFER CN801 033G8021 2E U INVERT CONNECTOR CN802 033G8021 2E F WAFER CN802 033G8021 2E U INVERT CONNECTOR CN901 087G 501...

Page 35: ...clk shield 22 clk 23 clk 24 GND 26 GND 25 CN102 NC R104 1K 1 16W 5 R138 NC DDC2_SDA C113 5pF 50V V_Sy nc ZD105 RLZ5 6B 1 2 FB102 BEAD R125 4K7 1 16W 5 VGA_PLUG RX1P R124 4K7 1 16W 5 A0 1 A1 2 A2 3 VSS 4 SDA 5 SCL 6 WP 7 VCC 8 U102 NC A0 1 A1 2 A2 3 VSS 4 SDA 5 SCL 6 WP 7 VCC 8 U101 NC C124 NC VCC3 3 VGA_R DDC2_SCL VGA_B RX2P R137 NC DSUB_5V VGA_PLUG VGA_G R122 NC C107 1000pF HDCP_CTRL 2 3 1 2 D108...

Page 36: ...8 LVA0P PA 0 9 LVB2M PB5 PA1 LVA3M LVB0M PB9 CMVCC PA6 LVA1P PPWR_ON 2 LVBCKP PB2 PA3 LVACKM LVBCKM PB3 LVB2P PB4 PA7 LVA1M Q301 AO3401 LVB1P PB6 R305 0 OHM 5 1 8W PANEL_VCC PB 0 9 PA 0 9 2 PB 0 9 2 AO3401L 2 1 C303 NC C304 NC S D R302 4K7 1 16W 5 3 G PANEL_VCC R301 330 OHM 1 4W C301 0 1uF 16V 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 CN301 CONN LVA0P RXE0 RX...

Page 37: ...03 300 OHM C710 0 1uF 16V C711 0 1uF 16V Mute BKLT EN 3 1 2 D702 NC DSUB_5V BKLT VBRI Volume BKLT EN CMVCC CMVCC R702 10K 1 16W 5 C706 100UF25V C701 0 1uF 16V R703 10K 1 16W 5 C708 0 1uF 16V C702 NC 1 2 3 4 5 6 7 8 9 CN701 CONN R705 10K 1 16W 5 R704 4K7 1 16W 5 C707 100UF25V C709 0 1uF 16V R706 1K 1 16W 5 Q701 2N3904S RTK PS MVCC_1 FB701 NC C705 0 1uF 16V DGND 1 2 3 CMVCC VCC1 8 Mute 2 Volume 2 on...

Page 38: ...M 1 16W R440 10K 1 16W 5 C434 0 1uF 16V PB9 R412 10K 1 16W 5 VCC3 3 PB5 VMPLL C416 NC R426 NC PB0 PA7 C409 0 1uF 16V PB 0 9 C402 10UF50V FB404 300OHM C423 0 22uF16V R403 0 OHM 5 1 8W 3 2 1 Q404 NC C422 0 1uF 16V LED_GRN BLUE C403 0 1uF 16V C410 0 1uF 16V AVDD C431 NC VDDC R420 120R 1 16W 5 VCC3 3 EE_WP C406 0 1uF 16V C407 0 1uF 16V C405 0 1uF 16V LED_GRN BLUE C414 0 1uF 16V VCC3 3 C435 0 1uF 16V R...

Page 39: ...uF 50V 65G0805103 32 D902 FR103 93G 6038T52T R925 3 6 K 1 1 8W 61G0805360 1F R926 1KΩ 1 8W 61G0805102 1 2 ZD903 RLZ13B 93G 39S 40 T VAR901 NC 61G 46 11 R937 1K 1 8W 61G0805102 R936 470 1 8W 61G0805471 C932 0 001uF 65G0603102 32 Q904 PMBS3904 57G 417 4 D904 NC R908 2KΩ 1 8W 61G0805202 C925 1UF450V 67G215S10915T3964 R930 100Ω 1 4W 61G1206101 C924 NC NC 1 2 JP903 BEAD 71G 55 29 R912 61G1206103 OTP 3 ...

Page 40: ... R832 3PF 3KV Q810 RK7002 R814 750K OHM 1 8W C817 0 1uF 0805 R819 82OHM 5 1 4W OPT2 R806 10KΩ 1 8W OPT3 C830 1uF 25V 61G0805102 R801 82OHM 5 1 4W OPT4 R829 82OHM 5 1 4W C828 0 1uF 1 2 JP934 BEAD C803 NC R818 82OHM 5 1 4W R822 C810 560PF 50V R840 1MΩ 1 8W C813 1000pF R805 470 1 4W 93G 64 33 C802 0 1uF 93G 6432S 61G0805102 3 1 2 D805 BAV99 93G 6432S 61G0805513 C816 12PF6KV VCC 61G1206519 R817 20K 1 ...

Page 41: ... 41 Oct 2008 P NO Printed in China h t t p w w w w j e l n e t ...

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