Xoceco LC-27R18, LC-32R18 Schematic

LCD TELEVISION

LC-27R18

LC-32R18

America

CONTENTS

Safety precautions………………………………………………………………………..…

Alignment instructions …………………………….…….………………………..…….…

Working principle analysis of the unit……………………………….………….………….

Block diagram…………………………………..……………………….………….………

IC block diagram………………………………………………………………………..……

Wiring diagram ……………………………………………………………..……………...

Troubleshooting………………………………………………………………………..……

Schematic diagram …………………………………………………………………….…..

APPENDIX-A: Main assembly list

APPENDIX-B: Exploded view

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

servicing please read the following points carefully.

Safety precautions

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

would be unable to work and no way to get it repaired.

2.11 Special care must be taken in transporting or handling it. Exquisite shock vibration may lead to breakage of screen glass or damage to driving circuit. Therefore it must be packed in a strong case before the transportation or handling.

2.12 For the storage make sure to put it in a place where the environment can be controlled so as to prevent the temperature and humidity from exceeding the limits as specified in the manual. For prolonged storage, it is necessary to house it in an anti-moisture bag and put them altogether in one place. The ambient conditions are tabulated as follows:

Temperature Scope for operation 0 ~ +50 oC

Scope for storage -20 ~ +60 oC

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 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 remain in the picture for a period of time (several minutes). But when operating it please avoid displaying still picture in high brightness for a long time.

3. Points for attention during installation

3.1 The front panel of LCD screen is of glass. When installing it please make sure to put it in place.

3.2 For service or installation it’s necessary to use specified screw lest it should damage the screen.

3.3 Be sure to take anti dust measures. Any foreign substance that happens to fall down between the screen and the glass will affect the receiving and viewing effect

3.4 When dismantling or mounting the protective partition plate that is used for anti vibration and insulation please take care to keep it in intactness so as to avoid hidden trouble.

3.5 Be sure to protect the cabinet from damage or scratch during service, dismantling or mounting.

Alignment instructions

1. Test equipment

PM5518 (Video signal generator) K-7253 (VGA signal generator) CA210 (White balancer)

2. The alignment flow chart (see below figure)

Check DDC, HDCP KEY and FLASH

Production of main board and analog board on the line.

Check CPU board and analog board

Combined test for general assembly

Connect to central signal source; check if various

TV functions (station skipping, modulate quantit

control etc), check if the output of earphone and

speaker are normal.

Input AV/S signal and HDTV signal; check various

functions under AV/S terminal

Input VGA signal and check if display is normal in

the state of PC and various functions (analog

quantity control, line/field center etc.)

Check accessories and then packing

3. The unit adjustment

Enter factory menu method: press the SOURCE→ 2→ 5→8→0 buttons one by one on the remote control to factory menu. Press the MENU button to select item. Press the DSP button to exit the factory menu.

3.1 EEPROM initialization and back light adjustment

Enter the firs page of factory menu, adjust item (OPTION-1 to 9, OPTION-2 to 5 and back light to 255(LG PANEL) or 0(SHARP and CMO panel), select the EEPROM initial after, press the VOL+

button, then display the DOING, still the DOING disappear and turn off the unit. Note: option-1 and option-2 function as follows:

Option-1 Option-2

Bit3 0: No memory function after power off for 10s

1: memory function after power off for 10s

Bit2,1 00: STANDBY

01: turn on

10: memory function of turn on

Bit0 0: without LOGO

1: With LOGO

0:no signal noise wave of TV

1:no signal blue screen of TV

00:complexion correction (OFF)

01: complexion correction (WEAK)

10: complexion correction (MIDDLE)

11: complexion correction (STRONG)

0: Video and Graphic channel white balance no share

1: Video and Graphic channel white balance no share

3.2 HDMI channel adjustment

Input the VG-848 TIME854(800X600/60Hz) and PATTERN92 8-LEVEL gray signal, enter the factory menu2(white balance adjustment menu), adjust the third step and the seventh step. Adjust R-OFFSET, G-OFFSET and B-OFFSET item, still the third step and the seventh step color coordinate to (285, 293). Adjust R-GAIN, G- GAIN and B- GAIN item, still the seventh step color coordinate to (285, 293). Repeat adjustment R-OFFSET, G-OFFSET and B-OFFSET item and R-GAIN, G- GAIN and B- GAIN item, still two step gray to (285, 293). Enter the factory menu3 (cool and warm color temperature difference menu):

R-offset-D

Warm

Cool

TV MODE

27CMO 0 -1 1 0 -7 -22

32LG 0 0 0 0 -9 -26

26SHARP -1 -1 1 0 -11 -27

32SHARP 2 3 3 0 -13 -25

27CMO 0 -1 0 -25 -9 0

32LG -1 1 0 -24 -5 0

26SHARP 0 0 0 -23 -7 0

32SHARP 5 3 2 -30 -11 0

27CMO

32LG 0 -7 0 0 0 0

26SHARP 0 -5 0 0 -3 0

32SHARP

elta

G-offset-D

elta

B-offset-D

elta

R-Gain-

Delta

G-Gain-

Delta

B-Gain-

Delta

Note: R-OFFSET, G-OFFSET and B-OFFSET values must be an item value to 128 at least; R-GAIN, G- GAIN and B- GAIN values must be an item value to 255 at least.

3.3 VGA channel adjustment

3.3.1 mode pre-set Input the VGA signal of VG-848 (PATTERN 980:1 dot ON/OFF), select the TIME877 (720x400/70Hz) signal, press auto-adjust button to all screen or adjust PC setting menu to auto correction. Separate auto adjust for TIME854 (800x600/60Hz) and TIME854 (800x600/60Hz).

3.3.2 VGA channel auto color adjustment Input the VG-848 TIME854(800x600/60Hz) and PATTERN920(GRAY 8 STEP(H)), enter the factory menu1, select the AUTO COLOR after, press the VOL+ button to select AUTO COLOR.

3.4 YPBPR channel adjustment

Input the VG-848 TIME972(1080i/60Hz) and PATTERN976(64 GRAY & Color), enter the factory menu1, select the AUTO COLOR after, press the VOL+ button to select AUTO COLOR.

3.5 Other setting Separate Factory Menu 4, Factory Menu 5, Factory Menu 6, Factory Menu 7 adjustment as follows:

Factory Menu 4 Factory Menu 6

Bright Max 148 Picture_Mode Soft Normal Bright

Bright Center 128 Brightness 50 50 55

Bright Min 78 Contrast 35 50 75

Contrast Max 154 Color 40 50 60

Contrast center 118 Sound_Mode Music Movie News

Contrast Min 28 Bass 80 50 30

Color Center 128 treble 60 50 40

Factory Menu 5

27CMO 32LG 26SHARP 32SHARP

Volume_1 48 52 S2310_Color 142

Volume_25 100 102 S2310_Contrast 120

Volume_50 114 116 S2310_Bright 133

Volume_100 123 121

Bright_Cen_Delt 0

Bright_Max_Delt 2

Cont_Cen_Delt 10

Cont_Max_Delt 12

Factory Menu 7

4. Performance check

4.1 TV function Input center source signal to RF-TV terminal, check if the channel is leak for auto searching.

4.2 AV/S and YPBPR terminal Input AV/S and HDTV signal, check if the signal is normal.

4.3 VGA terminal Input 640 x 480 @60Hz VGA format signal, check if the signal is normal.

4.4 HDMI terminal Separate input HDMI and DVI signal; check the picture and sound is normal, check if the HDCP function is normal.

4.5 check the sound channel

4.6 ex-factory setting Enter the first page of factory menu, select the factory out after, press the VOL+ button to display “doing”, then “doing” disappear while it can auto ex-factory setting.

Working principle analysis of the unit

The RF via integrative tuner TUNER1 after, the FBAS is generated. The FBAS, AV1/SVHS(SVHS priority) and AV2 and so on, its sent N7 (TVP5160) to switch selection and decode. The video is decoded and generates an AV output. The signal via N7 decode after, it sent 8-bit ITU-R656 format signal to N10 (FLI2310) non-interlaced processing. It sent 16bit YC signal to main processing control chip N15(GM1501/1601). Two ways YPBPR signal via HDTV switch N36(CBT3257C) selection after, it sent RGB switch N4(CT3257C) and 24bit RGB from pc signal to GM1501/1601. The HDMI via receiver N34(MST3383MB) processing after, it output VGA signal of 24bit to GM1501/1601. They sent to GM1501/1601 picture processing, therein YPBYP or RGB to A/D conversion after, it and other two signal are switched selection and digital display processing, it include OSD, GAMMA correction, brightness and contrast processing, then LVDS conversion to LCD panel display. The SIF of tuner output signal to audio processing NA6(MSP3420),The audio of AV1/SVHS/AV2 via switch conversion NA3(HEF4052) to MSP3420, the audio of two YPBPR via switch conversion NA5(HEF4052), the HDMI via MST3383MB decode to audio, it audio via N26(CS4334) D/A conversion to MSP3420, the audio of VGA sent to MSP3420. The stereo of the SIF with other four ways audio switch conversion selection to volume control and audio processing. it output right/left channel audio, one way signal sent SRS processing NA7 (M62494) to SRS sound stereo processing. It via sound amplifier NA9(TPA3008D2) to speaker; other way signal to earphone and AV OUT R/L output.

Block diagram

VGA

YPbPr 1 YPbPr 2

HDMI

AV/S IN 1

AV IN 2

Tuner

AV OUT

L/R_YPbPr1

L/R_YPbPr2 L/R_USB L/R_VGA L/R_HDMI

L/R_AV1 L/R_AV2

EDID

24C02

EDID

24C02

HDTV Switch

CBT3257C

HDCP KEY

24C04

HDMI RX

MST3383MB

YUV_SW

Audio Switch

TC4052

Audio Switch

TC4052

Hs Vs

R G B

HDTV Switch

CBT3257C

OPTION

Media Player

(USB)

Video Decoder Deinterlacer

TVP5160 FLI2310

SIF

L/R_

Y Pb/Cb Pr/Cr

YUV/USB

SC1_OUT ANA_IN1

SC1_L/R

SC2_L/R SC3_L/R

SC4_L/R

Audio Processor

MSP3420G

SN74AHC14

RGB Switch CBT3257C

YUV/VGA

DACM_L/R

SC2_OUT

Hs Vs

R G B

Y Pb/Cb Pr/Cr

EEPROM

Power_ON,IR,KeyA,KeyB,Led1,Led2 Mute,HP_SW,VGA_CAB,DVI_CAB YUV/VGA,YUV_SW,YUV/USB

Frash/ROM

LCD TV Controller

GM1601/GM1501

SRS Audio AMP

Head Phone

AMP

Frame Buffer

HP_SW

DDR

BK Control

PANEL

INVERTER

VBL

Power_ON,+5V_STB,VCC,VBL

Power Supply

IC block diagram

1.MSP3420

The MSP 34x0G family of single-chip Multistandard Sound Processors covers the sound processing of all analog TV-Standards worldwide, as well as the NICAM digital sound standards. The full TV sound processing, starting with analog sound IF signal-in, down to processed analog AF-out, is performed on a single chip. Figure 1–1 shows a simplified functional block diagram of the MSP 34x0G. This new generation of TV sound processing ICs now includes versions for processing the multichannel television sound (MTS) signal conforming to the standard recommended by the Broadcast Television Systems Committee (BTSC). The DBX noise reduction, or alternatively, Micronas Noise Reduction (MNR) is performed alignment free. Other processed standards are the Japanese FM-FM multiplex standard (EIA-J) and the FM Stereo Radio standard. Current ICs have to perform adjustment procedures in order to achieve good stereo separation for BTSC and EIA-J. The MSP 34x0G has optimum stereo performance without any adjustments. All MSP 34xxG versions are pin compatible to the MSP 34xxD. Only minor modifications are necessary to adapt a MSP34xxD controlling software to the MSP 34xxG. The MSP 34x0G further simplifies controlling software. Standard selection requires a single I2C transmission only. The MSP 34x0G has built-in automatic functions: The IC is able to detect the actual sound standard automatically (Automatic Standard Detection). Furthermore, pilot levels and identification signals can be evaluated internally with subsequent switching between mono/ stereo/bilingual; no I2C interaction is necessary (Automatic Sound Selection). The MSP 34x0G can handle very high FM deviations even in conjunction with NICAM processing. This is especially important for the introduction of NICAM in China. The ICs are produced in submicron CMOS technology. The MSP 34x0G is available in the following packages: PLCC68 (not intended for new design), PSDIP64, PSDIP52, PQFP80, and PLQFP64.

Fig. 1–1: Simplified functional block diagram of the MSP 34x0G

2. TVP5160

The TVP5160 device is a high quality; digital video decoder that digitizes and decodes all popular baseband analog video formats into digital component video. The TVP5160 decoder supports the A/D conversion of component YPbPr and RGB (SCART) signals, as well as the A/D conversion and decoding of NTSC, PAL, and SECAM composite and S-Video into component YCbCr. Additionally, component progressive signals can be digitized. The chip includes two 11-bit, 60-MSPS, A/D converters (ADCs). Prior to each ADC, each analog channel contains an analog circuit, which clamps the input to a reference voltage and applies a programmable gain and offset. A total of 12 video input terminals can be configured to a combination of YPbPr, RGB, CVBS, and S-Video video inputs. Progressive component signals are sampled at 2x clock frequency (54 MHz) and are then decimated to the 1x rate. In SCART mode the component inputs and the CVBS inputs are sampled at 54 MHz alternately, then decimated to the 1x rate. Composite or S-Video signals are sampled at 4x the ITU-R BT.601 clock frequency (54 MHz), line-locked for correct pixel alignment, and are then decimated to the 1x rate. CVBS decoding utilizes advanced 3D Y/C filtering and 2-dimensional complementary 5-line adaptive comb filtering for both the luma and chroma data paths to reduce both cross-luma and cross-chroma artifacts. 3D Y/C color separation may be used on both PAL and NTSC video signals. A chroma trap filter is also available. On CVBS and Y/C inputs, the user can control video characteristics such as hue, contrast, brightness, and saturation via an I2C host port interface. Furthermore, luma peaking with programmable gain is included, as well as a patented color transient improvement (CTI) circuit. Attenuation at higher frequencies or asymmetrical color subcarrier sidebands are compensated using the IF compensation block. Frame adaptive noise reduction may be applied to reduce temporal noise on CVBS, S-Video, or component inputs. 3D noise reduction and 3D Y/C separation may be used at the same time or independently. The TVP5160 decoder utilizes Texas Instruments’ patented technology for locking to weak, noisy, or unstable signals and can auto-detect between broadcast quality and VCR-style (nonstandard) video sources. The TVP5160 decoder generates synchronization, blanking, field, active video window, horizontal and vertical syncs, clock, genlock (for downstream video encoder synchronization), host CPU interrupt and programmable logic I/O signals, in addition to digital video outputs. The TVP5160 decoder includes methods for advanced vertical blanking interval (VBI) data retrieval. The VBI data processor (VDP) slices and performs error checking on teletext, closed caption, and other VBI data. A built-in FIFO stores up to 11 lines of teletext data, and, with proper host port synchronization, full-screen teletext retrieval is possible. The TVP5160 decoder can pass through the output formatter 2x sampled raw Luma data for host-based VBI processing. Digital RGB overlay can be synchronously switched with any video input, with all signals being oversampled at 4x the pixel rate.

INTERNAL BLOCK DIAGRAM:

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