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XOCECO LC15H3S, Service Manual, Page: 25 / 31

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XOCECO LC15H3S Service Manual Download Page 25

TV board troubleshooting

No picture but have raster.

Measure the waveform of 

R.G.B Hors, Vers at X7. 

Check whether N1 has 

5V power supply.

Check whether X9 pin 1, pin 2 have 

5V power input.

Replace N2

Replace V105-V17.

Replace N1

Measure N1 pin 33, pin 35 

waveform.

Measure N1 pin 42, pin 44 

waveform.

Check V105-V107's 

output waveform. 

No

Yes

Yes

Yes

No

No

No

No

No

24

Summary of Contents for LC15H3S

Page 1: ...LCD TV LC17H3S LC20H3S LC15H3S ...

Page 2: ... fire or damage to the set 2 4 Never operate the set or do any installation work in bad environment such as wet bathroom laundry kitchen or nearby fire source heating equipment and devices or exposure to sunlight etc Otherwise bad effect will result 2 5 If any foreign substance such as water liquid metal slices or other matters happens to fall into the module be sure to cut the power off immediate...

Page 3: ...or storage 20 60 C humidity Scope for operation 20 85 Scope for storage 10 90 2 13 Display of a fixed picture for a long time may result in appearance of picture residue on the screen as commmonly called ghost shadow The extent of the residual picture varies with the maker of LCD screen This phenonmenon doesn t represent failure This ghost shadow may remain in the picture for a period of time seve...

Page 4: ...n board TV board on line Check main board Check TV board Combined test for general assembly Connect to central signal source check if various TV functions station skipping modulate quantity control etc check if the output of earphone and speaker are normal Input SCART AV S signal check different functions of SCART AV S terminals Adjust TV board Input TV AV S terminal SCART VGA signals select separ...

Page 5: ...stment 2 5 1 IF adjustment a Input DV 5V into TP2 input 12V to TP6 Input 5V to TP4 and input 0V to TP5 monitor voltage of TP3 input 38 9 MHz signal to TP1 and use a non inductance screw driver to adjust IFT L207 so that TP3 voltage is 1 65V b Input DC 5V into TP2 input 12V to TP6 Input 0V to TP4 and input 5V to TP5 monitor voltage of TP3 input 33 9 MHz signal to TP1 adjust potential meter RP202 to...

Page 6: ...blue to make x 284 y 299 This procedure may not be taken now f Enter AV mode input 8 grey degree signal adjust tint to 0 adjust brightness and contrast measure sixth degree with CA 210 make Y to 180 cd m2 enter factory menu fix green to be 50 adjust red blue to make x 284 y 299 Notice For the best discrimination rate of LCD screen see table 1 Table 1 LCD resolution of best Screen size Factory LCD ...

Page 7: ...CVBS signal color bar multi wave group observe if the picture of the set is normal The normal screen should be AV1 change SCART signal to RGB format the normal screen should be AV1 RGB c Disconnect SCART signal the set could come back to current TV state Note This special function is not applicable to VGA 3 5 VGA connector Input VGA signal K7253 signal generator input different VGA format signal l...

Page 8: ... signal receiving Maybe broadcast signal itself is not good Check if the outdoor antenna is disconnected Check if the antenna is correctly oriented Fringe in picture Check if the antenna is correctly oriented Maybe there is electric wave reflected from hilltop or building Picture is interfered by stripe shaped bright spots Possibly due to interference from automobile train high voltage transmissio...

Page 9: ...he liquid crystal TV set and make proper adjustment according to the signal types Picture too bright and there is distortion in the brightest area Check if the contrast setting is too high Possibly the output quality of DVD broadcaster is set too high It maybe also due to improper terminal connection of the video frequency signal in a certain position of the system Picture is whitish or too bright...

Page 10: ...h may lead to incorrect display of the liquid crystal TVIn this case please press auto key on the remote control so as to enable the liquid crystal TV set to recheck the signal and then to display correct picture signal Method of software upgrading Steps of software upgrading are as follows 1 Select a serial connection wire and a VGA connection wire and then connect them by means of a patch panel ...

Page 11: ... receiver adopts LG 20 1 inch LCD display screen as display unit It has PAL SECAM B G I D K L L color system receiving functions and at the same time with AV input S VHS input PC VGA connector and earphone output and other signal connectors The power supply is outer connection of 12V power supply adaptor LC15 17 20H3S multi media LCD TV broadcast receiver consists of RF video signal board assy dig...

Page 12: ...in processor IC PW1306 PW1306 is a main processing IC built in type X86 CPU with outer memory 8M Flash N20 and controls the whole system The input signal from V port and G port is subject to internal arithmetic process and then output in R G B of 24 bit TTL to sockets JP3 JP4 Through connection line the signal is sent to LG LCD screen port for the realization of the picture re display Converter DS...

Page 13: ...BLOCK DIAGRAM 12 ...

Page 14: ...d Ground Ground Ground VCC CTL H IN1 L IN2 Red 1 input Green 1 input Blue 1 input Red 2 input Green 2 input Blue 2 input VD 1 input VD 2 input VD output Blue output Composite sync output Composite video input Sync on Green Green output Red output HD output HD 2 input HD 1 input HD Sync signal detector BA7657F BA7657S ...

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Page 17: ... GPIO PWM IR Decoder A 19 1 D 15 0 CS 1 0 2 Wire Serial Microprocessor Bus Memory Out Bus Memory Buffer Processor Memory Interface Memory In Bus OSD VYUV 7 0 VCLK VPEN PW130 ImageProcessor Internal Block Diagram ADC VIDEO PORTD 7 0 Sync Processing HS HSYNC VSYNC SOG Stripper SOGIN FILT PLL CLK R AIN G AIN B AIN A D Clamp A D Clamp VS Pow erOn Reset RESET Reset XI XO PLL and Oscillator MCLK DCLK UC...

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Page 21: ...hift AFC Standard Supply ÏÏ ÏÏ ÏÏ L switch VCO 21 20 18 Loop filter 14 Ï Offset comp optional 26 FPLL 0 90 VIF amp 6 7 8 15 VIF CAGC CBL Take over point SIF input switch CAGC 22 12 4 9 16 13 Standard switch 23 VS Ï Ï 17 CRef Intercarrier FM NICAM 24 FM det AM det SIF amp 25 AF AM AFC Video 95 10851 Ï Video det Control ÏÏ ÏÏ 19 AFC switch Ï Ï ÏÏ Figure 1 Block diagram ...

Page 22: ...V R L R Audio L S video HIGH VOLTAGE HIGH VOLTAGE MSP3420G ...

Page 23: ...ight size remains unchanged 3 Definition of dark spot It is identified as a dark spot if it is dark in the state of white field and its dark size remains unchanged 4 Definition of two neighboring points Defects of a group of picture elements RB RG GB 15 17 20 Sell area Europe Europe Europe America LCD panel Samsung 335 15012 00 Samsung 335 17050 00 Chimei 335 2000F 00 Back light board 667 L15H3 14...

Page 24: ... signal Check whether U1 pin 11 have output waveform Check N8 pin3 pin 5 s input signal Replace N8 Yes No Yes No No No Yes No No 23 Troubleshooting guide No raster Does the logo appear on the screen when turning on the set Check whether the adapter supply 12V power to Digital Board Check whether X101 is properly inserted Check U125965V Check whether FUSE is melted Replace adapter Check whether U18...

Page 25: ...G B Hors Vers at X7 Check whether N1 has 5V power supply Check whether X9 pin 1 pin 2 have 5V power input Replace N2 Replace V105 V17 Replace N1 Measure N1 pin 33 pin 35 waveform Measure N1 pin 42 pin 44 waveform Check V105 V107 s output waveform No Yes Yes Yes No No No No No 24 ...

Page 26: ...LC15H3S 01 ...

Page 27: ...LC15H3S 02 ...

Page 28: ...LC15H3S 03 ...

Page 29: ...LC17H3S ...

Page 30: ...LC20H3S 01 ...

Page 31: ...LC20H3S 02 ...

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