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Safety instructions 

1. Instructions

 

Be sure to switch off the power supply before replacing or welding any components   or 
inserting/plugging in connection wire Anti static measures to be taken (throughout the entire 
production process!): 
a) Do not touch here and there by hand at will; 
b) Be sure to use anti static electric iron; 
c) It’s a must for the welder to wear anti static gloves. 
Please refer to the detailed list before replacing components that have special safety requirements. 
Do not change the specs and type at will. 

 

2. Points for attention in servicing of LCD 

2.1 Screens are different from one model to another and therefore not interchangeable. Be sure to 
use the screen of the original model for replacement.   
2.2 The operation voltage of LCD screen is 700-825V. Be sure to take proper measures in 
protecting yourself and the machine when testing the system in the course of normal operation or 
right after the power is switched off. Please do not touch the circuit or the metal part of the module 
that is in operation mode. Relevant operation is possible only one minute after the power is 
switched off.   
2.3 Do not use any adapter that is not identical with the TV set. Otherwise it will cause 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 immediately and do not move anything on the module lest it 
should cause fire or electric shock due to contact with the high voltage or short circuit. 
2.6 Should there be smoke, abnormal smell or sound from the module, please shut the power off at 
once. Likewise, if the screen is not working after the power is on or in the course of operation, the 
power must be cut off immediately and no more operation is allowed under the same condition.   
2.7 Do not pull out or plug in the connection wire when the module is in operation or just after the 
power is off because in this case relatively high voltage still remains in the capacitor of the driving 
circuit. Please wait at least one minute before the pulling out or plugging in the connection wire. 
2.8 When operating or installing LCD please don’t subject the LCD components to bending, twisting 
or extrusion, collision lest mishap should result.   
2.9 As most of the circuitry in LCD TV set is composed of CMOS integrated circuits, it’s necessary 
to pay attention to anti statics. Before servicing LCD TV make sure to take anti static measure and 
ensure full grounding for all the parts that have to be grounded.   

 

2.10 There are lots of connection wires between parts behind the LCD screen. When servicing or 
moving the set please take care not to touch or scratch them. Once they are damaged the screen 

Attention: 

This

 

service manual is only for service personnel to take reference with. Before 

servicing please read the following points carefully. 

 

 

Summary of Contents for LC-23Y18

Page 1: ...LCD TELEVISION LC 23Y18 America...

Page 2: ...grading The unit working principle analysis Block diagram IC block diagram Identification criteria for the bright spot and dark spot of the LCD screen Wiring diagram Troubleshooting charts Schematic d...

Page 3: ...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 immediately and do not move anything on the mod...

Page 4: ...of picture residue on the screen as commonly called ghost shadow The extent of the residual picture varies with the maker of LCD screen This phenomenon doesn t represent failure This ghost shadow may...

Page 5: ...voltage to be 12v and 5v 3 3 main board adjustment 3 3 1 IF amplifier adjustment a Turn off the J201 J202 J203 J204 J205 and J5 input 38MHz PAL SYSTEM and 45 75MHz N Write memory N300 and N400 To pro...

Page 6: ...nate 0 293 0 008 g Repeat e step to f step it must be measure a true value h The unit without VGA interface of 20 N system you should be rework c step enter VIDEO channel input Gray H 16 for NTSC syst...

Page 7: ...electrical connector or the antenna Check if the antenna is properly connected Fringe in picture Check if the antenna is correctly oriented Maybe there is electric wave reflected from hilltop or buil...

Page 8: ...system Picture is whitish or too bright in the darkest area of the picture Check if the setting for the brightness is too high Possibly the brightness grade of DVD player broadcaster is set too high N...

Page 9: ...board especially for Y main board The steps for updating software 1 Install Gprobe 5 0 The first Double click the GProbe5 1 0 0 15_S0006 EXE 09A to install it According to the prompt of Windows and f...

Page 10: ...VGA cable connect the other end to the VGA interface of the LCD 6 Turn on the LCD 7 Run Gprobe5 Click the icon of Set the Device to Parallel The click the item of Delays and Buffer Size Set Long to 50...

Page 11: ...just need to click the pull down menu to select the desired Batch file and execute it in the following screen Note Do not cut off the power or turn off the unit during the burning process or the flash...

Page 12: ...sent to FLI8125 directly For the NTSC system when the RF signal is input to the NTSC tuner the turner generates IF signal Then the IF signals goes through the pre amplifying circuit and 45 75M SAW th...

Page 13: ...11 BLOCK DIAGRAM...

Page 14: ...e inner IC block diagram and function 1 Inner block diagram of M52760 IF signal processing IC AFT QIF VIDEO OUT Descriptions of the pins Pin Description Pin Description 4 5 VIF input 13 QIF OUT 7 1ST_...

Page 15: ...13 2 Inner block diagram of LA72700 stereo decoder...

Page 16: ...multi channel selector HEF4052BT while the audio signal from the AV inputs is sent to R2S15900SP directly After the processing of bass treble balance and AVL by R2S15900S all these processed audio sig...

Page 17: ...15 5 Inner block diagram of TPA1517 6W stereo audio amplifier...

Page 18: ...D_SEL_1 10 RESETn Reset 52 AUD_SEL_2 15 XTAL Resonator output 63 PBIAS Panel s oblique line control 16 TCLK Basic clock 64 PPWR Backlight adjustment 24 SCL_RS232 SCL_RS232 90 DEN Display data 25 SDA_R...

Page 19: ...mm 5mm Total defected point 8 7 5 4 Notes 1 Definition of defected point bright spot dark spot It is identified as a defected point if its area exceeds 1 2 of a single picture element R G B 2 Definiti...

Page 20: ...18 Wiring diagram Button board B Button board A Right speaker Left speaker Back light board Power board Main board indicator light board...

Page 21: ...ainboard Vcc 18V X702 1 2 12V 3 4 GND 5 6 18V 7 8 GND 9 PBIAS 10 PWM 1 No raster no picture and no sound When the main power is turned on the unit s indicator lights up in red red indicator is control...

Page 22: ...ent from the actual frequency Connect the signal cable manually adjust the frequency to conform to the actual frequency Enter into service menu check AFT value should be about 1 6V If the difference i...

Page 23: ...ce D502 Check whether pin1 of N501 has wave Replace N502 Check whether N502 is damaged Replace N505 Check whether N505 is damaged Check whether N505 D507 is damaged Replace the damaged parts Y Y Y N Y...

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Page 31: ...APPENDIX A Exploded View...

Page 32: ...een 15 804 20429 00 Connecting board 16 360 30042 00 Power switch 17 870 10285 00 Power supply socket bracket 18 870 3A189 AF0 USB bracket 19 780 U18W1 AW0 Front cover 20 808 2C331 00 ACTIVE panel 21...

Page 33: ...A remote control 615 10629 01 Stand assy GZ 2323S 615 20506 01 Bottom speaker assy 667 LUY25 01U Main board assy 667 L23S18 09 Infrared receiving board assy 667 L23Y18 05A Button board assy 667 L23Y18...

Page 34: ...603 L23Y180 10 America Ver 1 0...

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