Xoceco LC-37T19 Schematic

LCD TELEVISION

LC-37T19

CONTENTS

Safety Precautions………………………………………………………………………..…

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

Software upgrade method…………………………………………….……………………

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

Block diagram………………………………………………………………………………

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

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

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

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

APPENDIX-A: 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 (LC-37T25& LC-42T17&LC-47T17)

1. Test equipment

Digital multimeter, signal generator (54200) VG849 (HDMI signal generator) CA210 (White balancer)

2. The alignment flow chart (see below Fig.1)

Write N105, N403, N607, N70, N606

To produce main board, TV board and other board

Check the TV board

Check accessories and then packing

Check the MAIN board

Input VGA signal source, check is the display is

ormal in PC state and various function (analog

control) H-V center etc. The AV-out output soun

Check the buttons board and IR receive board

is originally signal

Combined test for general assembly

Aging

ADC correction and white balance adjustment

Input the center signal source, check if various functions of TV (search channel, system identify and analog control etc.), earphone output, speake output and the picture and sound of AV-out is

Input HDMI and DVI signal source, check if the HDCP KEY is normal. The AV-out outpu

sound is originally signal

Input YpbPr/YcbCr 1/2 signal source; check if the

icture and sound analog control is normal in the COMPONENT state. The AV-out output sound is ori

inally signal

Input AV1/S/AV2 signal source, check if the various terminal functions (system identify an analog control etc.) and the picture and sound o AV-out is normal.

Fig.1 Flow process of alignment

3. Alignment instructions

3.1 the main board adjustment a. Connect the X602 of main board to the infrared receive board, the supply power plug to X1, then

the indicator of the infrared receive board is red light.

b. Press the POWER button; the indicator change to blue light, the LED1 of main board is flicker of

slow. c. Write program to N102 d. Check if various channels are normal.

3.2 The TV board adjustment a. Connect the high frequency board to main board, and connect the X501 and X502 to the supply

power. b. Press the POWER button, the indicator change to blue light. c. Check if the picture and sound of TV/AV1/AV2/S/YPBPR1/TPBPR2 and sound of HDMI/VGA

channels are normal. Check the STEREO and SAP. Check the picture and sound of the

TV/AV1/S/AV2.

3.3 the unit adjustment After install the unit, check it is normal working.

3.4 Aging a. Select the TV channel, the screen is noise wave of no signal TV b. Aging an hour.

3.5 ADC correction and white balance adjustment (use white balancer CA210 and signal generator VG849) Enter the factory menu method: press “1”→ “9” → “7” → “9” button in the window menu state. Note: warm color temperature coordinate (285, 294); warm color temperature coordinate (284, 299). LC-42T17, LC-47T17 and LC37T25/T7 cool color temperature coordinate (270, 283).

3.5.1 HDMI channel a. Input 8 level gray signal 720p/60Hz. b. Brightness to 50, contrast to 50. c. Color temperature to warm. d. Enter color temperature setup menu. e. Adjust RED GAIN, GREEN GAIN, BLUE GAIN, until the fifth level color coordinate (270, 283).

3.5.2 D-SUB channel a. Input the 16 level gray signal 1027 x 768 @ 60(TIMING: 889, PATTERN: 921) b. Brightness to 50, contrast to 50. c. Enter the ADC auto correction d. Color temperature to warm. e. Enter the color temperature setup menu. f. Input the 8 level gray signal 1027 x 768 @ 60(TIMING: 889, PATTERN: 920) g. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the third level color coordinate

(284, 299). h. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (284,

299). i. Repeat the g and h step, until the third and the seventh level color coordinate (284, 299). j. Color temperature to cool. k. Enter the color temperature setup menu. l. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the third level color coordinate

(270, 283).

m. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (270,

283). n. Repeat the L and M step, until the third and the seventh level color coordinate (270, 283).

3.5.3 high definition channel a. Input the 720P SMPTE COLOR BAR signal (TIMING: 976, PATTERN: 984). b. Brightness to 50, contrast to 50. c. Enter the ADC auto correction. d. Color temperature to warm. e. Enter the color temperature setup menu. f. Input the 8 level gray signal 720b/60Hz(TIMING: 976, PATTERN: 920). g. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the fourth level color

coordinate (284, 299).

h. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (284,

299). i. Repeat the g and h step, until the fourth and the seventh level color coordinate (284, 299). j. Color temperature to cool. k. Enter the color temperature setup menu. l. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the fourth level color

coordinate (270, 283).

m. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (270,

283). n. Repeat the l and m step, until the fourth and the seventh level color coordinate (270, 283). o. Holding the pattern signal, change the timing signal, repeat the G to the M step for 480i, 480p,

and 1080i signal.

3.5.4 the VIDEO channel a. Input the eight level gray signal of PAL b. Brightness to 50, contrast to 50. c. Enter the factory menu. d. Color temperature to warm. e. Enter the color temperature setup menu. f. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the fourth level color

coordinate (284, 299).

g. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (284,

299). h. Repeat the f and g step, until the fourth and the seventh level color coordinate (284, 299). i. Color temperature to cool. j. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the fourth level color

coordinate (270, 283).

k. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (270,

283). l. Repeat the j and k step, until the fourth and the seventh level color coordinate (270, 283).

3.5.5 the RF channel a. Input the center signal source, set to D-8 channel b. Brightness to 50, contrast to 50. c. Enter the factory menu. d. Color temperature to warm.

e. Enter the color temperature setup menu. f. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the third level color coordinate

(284, 299).

g. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (284,

299). h. Repeat the f and g step, until the third and the seventh level color coordinate (284, 299). i. Color temperature to cool. j. Adjust the RED OFFSET, GREEN OFFSET, BLUE OFFSET, until the third level color coordinate

(270, 283).

k. Adjust the RED GAIN, GREEN GAIN, BLUE GAIN, until the seventh level color coordinate (270,

283). l. Repeat the j and k step, until the third and the seventh level color coordinate (270, 283).

4 Performance check

4.1 TV terminal Input the center signal source to RF terminal, enter searching menu → auto search, check if the leak channel, half-auto search channel, fine tune, earphone and speaker are normal. Check the AV OUT.

4.2 AV1/S/AV2 input terminals Input AV1/S/AV2 signal source, check the picture and sound.

4.3 VGA terminal Input the VGA signal (K7253 signal generator), separate input VGA format signal of table 1, check the picture and sound

Table1 PC display format signal

No. Resolution H-frequency(kHz) V-frequency(Hz)

1 720 x 400 31.47 70.08 25.17 DOS

2 640 x 480 31.50 60.00 25.18 DOS

3 640 x 480 37.90 72.00 31.50 Mac.(SOG)

4 640 x 480 37.50 75.00 31.50 VESA

5 640 x 480 43.30 85.00 36.00 VESA

6 800 x 600 35.16 56.25 36.00 VESA

7 800 x 600 37.90 60.00 40.00 VESA

8 800 x 600 46.90 75.00 49.50 VESA

9 800 x 600 48.08 72.19 50.00 VESA

10 832 x 624 49.00 74.00 57.27 Mac.(H+V)

11 1024 x 768 48.40 60.00 65.00 VESA

12 1024 x 768 56.50 70.00 75.00 VESA

13 1024 x 768 60.00 75.00 78.75 VESA

14 1280 x 1024 64.00 60 108.00 SXGA

15 1280 x 1024 80.00 75 135.00 SXGA

16 1600 x 1200 75.00 60 162.00 UXGA

pixel clock pulse

frequency(MHz)

4.4 YPbPr terminal Input the YPbPr signal source (K7253 signal generator), separate input format signal in table of

remark

table 2, check the picture and sound.

Table 2 Component format signal

No. H-frequency(kHz) V-frequency(Hz) signal

1 15.735 60 SDTV 480i

2 15.625 50 SDTV 576i

3 31.47 60 SDTV 483p

4 45.00 60 HDTV 720p

5 33.75 60 HDTV 1080i

6 28.13 50 HDTV 1080i

7 67.50 60 HDTV 1080p

8 56.25 50 HDTV 1080p

4.5 HDMI terminal Input the DHMI signal source (VG849 signal generator), separate input format signal in table of table 3, check the picture and sound.

Table 3 HDMI format signal

No. H-frequency(kHz) V-frequency(Hz) signal

1 15.735 60 SDTV 480i

2 15.625 50 SDTV 576i

3 31.47 60 SDTV 483p

4 45.00 60 HDTV 720p

5 33.75 60 HDTV 1080i

6 28.13 50 HDTV 1080i

HDMI format signal of audio

channel 2

sampling rate support 32Kbit/s 44.1Kbit/s 48Kbit/s

bit wide support 16bit,20bit,24bit

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;

2. Use a serial wire to connect the PC to the patch panel and set TV set to off state;

Open the software upgrade file holder and double click FlashUpgrader.exe (window

2000/XP/NT) The following interfaces will show up after running the program:

Based on the computer features, set up the serial port (COM Port). Select corresponding serial port (if it’s unable to FLASH WRITE, change to another port). Baud is selected to be 115200. Then select Reset Target After Download. Click FLASH pushbutton, it’s ready to run. For other settings, please refer to the Fig. Above (already defaulted by the system, normally no need to change). Switch on TV set the FLASH write program begins to run;

When the upgrading is complete, a window (below) will be opened. Press “Finish” button to complete the process.

Note: Do not shut the power off or turn the TV set on during the FLASH write. Otherwise it may lead to no way for flash to rewrite.

Working principle analysis of the unit

The unit has two MCU, the main MCU is PW218 (N601): it is used to control all the chips’ working status on the main board (including image processing, channel switch, sound processing, image display etc.), sub CPU, OSD, searching channels, image effect adjustment, buttons control, infrared remote control etc.; the sub CPU is ATMEGA8L (N606): it is used to control power supply, including standby and turning on the unit by using remote control etc.. The two MCU correlates with each other through pin 14 INT (interruption) of ATMEGA8L, pin 28 and 29 SDA, SCL. The unit has one integrative tuner (including HF and IF amp. circuits). The signal received by antenna is sent to tuner, under the control of MCU PW218 (N601) SDA and SCL, proper channel selection and right system switching will be done by the tuner, then video signal and audio signal will be output by the tuner through decoding and by high and intermediate amplification. Video signal of the tuner will then be sent to Decoder PW2300 (N201). Audio signal of the tuner will then be sent to AV switch box M52797 (N400), the audio signal of AV1, AV2 and HD2 of the main board will also be sent to M52797 (N400) at the same time. The selected audio signal after switching will be sent to R2S15900 (N301), and then switching selection will be done towards the above audio signal together with the audio signal of VGA, HDMI and HD1. The two chips are controlled by PW218 (N601), after the above process the finally selected way will be set to X300 earphone socket after under the control of volume, treble and bass which is finished by R2S15900 (N301), the earphone socket has the switching function, when earphone is plugged, sound will be sent to earphone amplifier NJW1109 (N302), then sent back to earphone socket after power amplification. If earphone is unplugged, sound will be sent to sound amplifier TPA3008 to do amplification and then sent to speaker. Image parts: Video signal of the tuner will be sent to AV switch box M52797 (N400), video signal of AV1 and AV2 will also be sent to M52797 (N400) at the same time, two groups of video output will be obtained after switching, one group of video output together with its audio output will be sent to AV_OUT terminal to treat as AV OUT. The other group of video output together with other video signals such as S-VIDEO, YpbPr1, YpbPr2 and VGA will be sent to PW2300 to do video decoding or AD transformation, then output 24bit digital RGB signal and some corresponding synchronous signals. Items such as 3D comb filter, channel switching, 5 lines Y/C separation and color decoding etc. are primarily done by PW2300. 24bit digital RGB signal and some corresponding synchronous signals outputted by PW2300 will then be sent to PW218 (N601). HDMI signal will also be sent to AD9398 (N101) to de decoding and output 24bit digital RGB signal as well as some corresponding synchronous signal, which will be sent to PW218 (N601). PW218 is a new generation chip of Pixelworks, which has ability to deal with images, 24bit digital RGB signal and some corresponding synchronous signals outputted by AD9398 and PW2300 will be sent to this chip to deal with images. The chip has functions such as converting from interleaved into line-by-line and image enhancement etc.. PW218 has SCALER function which can do format conversion towards different input formats so as to meet the format needs of the screen and finally output 24bit RGB signal. The interface standard of PDP screen is generally LVDS (low voltage differential signal), so the digital RGB signal outputted from PW218 is needed to send to converting interface chip N6 DS90C387 of LVDS to obtain LVDS signal, then it will be sent to the screen. PW218 is also the main CPU, its programs are stored in periphery device flash N701, and software upgrade through RS-232 interface is virtually upgrading the stored programs through PW218 towards N701.

Chief functions: High definition 1080P LCD 16:9 wide screen Support several kinds of HDTV wide voltage range, low standby power consumption (less than 1W) One group of D-SUB, S-VSH (Y/C), RS232, AVOUT, HEADPHONE, HDMI, two groups of YPbPr/YCbCr, AV.

Block diagram

RF Audio

RF V ideo

YPbPr1 YPbPr2

EEPROM

LA72700V

STERO/SAP decoder

Audio and video

MAX3232C

KEY

N400

M52797SP

switch

AD9880 AD9398

SRS processor

M62494

PW2300

memory

PCM1742

I2S D/A

PC Audio HDMI Audio

R2S15900

TPA3008D2

NJW1109

AV Audio Out

V port

G port

Flash

PW218

DDR 256M

SDRAM

I2C1

Earphone

socket of

with switch

I2C2

MEGAL8

DS90C387 LCD panel

EEPROM

24LC32

KEY

IC block diagram

1. AD9880 and AD9398

AD9880 have HDMI digital and analog terminal of working frequency 165Hz, it support 1080P (non-interlaced scanning) and UXGA (1600 x 1200/60Hz) video format, also it support eight audio channel of 192KHz. AD9398 without analog terminal. Internal Block Diagram

PIN configuration

AD9880 (AD9398) PINS FUNCTIONS

Pin Name Function Pin Name Function

2-9 GGE(0-7) Converter output 44 RXC+ DVI input

12-19 GBE(0-7) Converter output 49 DDC_CLK HDCP Slave Serial Port

Data Clock

92-99 GRE(0-7) Converter output 50 DDC_DATA HDCP Slave Serial Port

Data I/O

20, 21 MCLK Control clock output 51 MCL HDCP Master Serial Port

Data Clock

22 I2S_SCK Audio serial clock output 52 MDA HDCP Master Serial Port

Data I/O

23 I2S_WS Bus clock data output 82 SCL-1 Serial Port Data Clock

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