Akira LCT-20PSST User manual

LCT TV

Service Manual

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Model No.: LCT-20PSST Version: 1.0

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CONTENTS

SAFETY PRECAUTIONS....................................................................................................................... 4

ALIGNMENT INSTRUCTION............................................................................................................... 6

METHOD OF SOFTWARE UPGRADING ............................................................................................ 9

BLOCK DIAGRAM ..............................................................................................................................13

IC BLOCK DIAGRAM .........................................................................................................................14

WIRING DIAGRAM............................................................................................................................. 18

INDENTIFICATION CRITERIA FOR THE BRIGHT SPOT & DARK SPOT.................................... 19

TROUBLE SHOOTING ........................................................................................................................ 26

EXPLODED VIEW................................................................................................................................ 31

PART LIST............................................................................................................................................. 32

Model No.: LCT-20PSST Version: 1.0

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SAFETY PRECAUTIONS

1. Instructions

Be sure to switch off the power supply before replacing or welding any components 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

a. Screens are different from one model to another and therefore not interchangeable. Be sure

to use the screen of the original model for replacement.

b. 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 witched 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.

c. Do not use any adapter that is not identical with the TV set. Otherwise it will cause fire or

damage to the set.

d. 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.

e. 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.

f. 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.

g. 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.

Model No.: LCT-20PSST Version: 1.0

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h. When operating or installing LCD please don’t subject the LCD components to bending,

twisting or extrusion, collision lest mishap should result.

i. As most of the circuitry in LCD TV set is composed of CMOS integrated circuits, it’s

necessary to pay attention to anti static. Before servicing LCD TV make sure to take anti

static measure and ensure full grounding for all the parts that have to be grounded.

j. 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.

k. Special care must be taken in transporting or handling it. Exquisite chock vibration may leas

to breakage of screen glass or damage to driving circuit. Therefore it must be packed in a

strong case before the transportation or handling.

l. 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

Scope for storage -20 ~ +60oC

Humidity Scope for operation 20% ~ 85%

Scope for storage 10% ~ 90%

m. 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 “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

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

place.

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

screen.

c. 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.

d. 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.

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

mounting.

Model No.: LCT-20PSST Version: 1.0

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ALIGNMENT INSTRUCTION

1. Test equipment

PM5518 (Video signal generator)

K-7253 (VGA signal generator)

CA210 (White balancer)

2. The alignment flow chart

Production of main board and TV board on the line

Check the main board and supply power board

Combined test for general assembly and aging

ADC correction and white balance adjustment

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 AV/S signal and HDTV signal; check

Written N101 and N304

various functions under AV/S terminal

Model No.: LCT-20PSST Version: 1.0

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3. Written program

Written program of IC(N101, N304)

4. Main board adjustment

a. According to wiring diagram, connect main board to supply power, the indicator to red.

b. Press the POWER button in the senor control, the indicator to blue.

c. Check the picture and sound is normal of TV /SCART /YPBPR /RGB /DVI channel.

5. Aging

a. Install the set.

b. Turn on the set, select the TV channel, then let the set no signal in state.

c. Aging one hour.

6. White balance

a. Enter RGB channel

b. Input grid signal (C_Hat_16x12(w)) of 60Hz of VGA terminal, resolution to 640 x 480 of in

optimum resolution. Adjust H-center and V-center, let to the picture normal.

c. Input gray (H)-16 signal, enter the factory menu, select “VGA AUTO COLOR”

d. Exit the factory menu, select the YPBPR /YCBCR channel.

e. Input the YPBPR signal, adjust different signal.

f. Input gray (H)-8 signal, using the CA-210 test the third level, adjust brightness and contrast,

let brightness to 180nit, enter factory menu, still the green color temperature value, adjust

blue color temperature and red color temperature, let to x = 0.28 ± 0.02, y = 0.299 ± 0.02.

Input VGA signal and check if display is normal

in the state of PC and various functions (analog

quantity control, line /field center etc.)

Input YpbPr /YcbCr signal, check the screen display is

normal in the various channel and various functions

(analog quantity control, line /field center etc.)

Check accessories and then packing

Model No.: LCT-20PSST Version: 1.0

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7. Performance inspection

a. TV function

Enter the search menu → auto search, connect RF-TV terminal to the central signal source,

check if there is station skipping.

b. AV /S input terminal

Input AV /S signal, check the picture and sound is normal.

c. VGA terminal

Input the VGA signal (table 1), and auto correction it, check the picture and sound is normal.

Table 1: VGA signal format

Resolution Pixel clock (MHz) H-SYNC (KHz) V-SYNC (Hz)

640 x 480 @ 60 25.175 31.469 59.900

640 x 480 @ 75 31.500 37.500 75.000

720 x 400 @ 70 28.322 31.469 70.086

800 x 600 @ 60 40.000 37.879 60.317

800 x 600 @ 75 49.500 46.875 75.000

d. YPBPR /YCBCR terminal

Input YPBPR /YCBCR signal (table 2) and auto correction it, check the picture and sound is

normal.

Table 2: YpbPr /YcbCr signal format

Resolution Pixel clock (MHz) H-SYNC (KHz) V-SYNC (Hz)

768 x 576 @ 50i 14.750 15.625 50

776 x 482 @ 60i 15.734 15.734 60

720 x 480 @ 60p 27.027 31.500 60

720 x 576 @ 50p 27.000 31.250 50

1280 x 720 @ 60p 74.250 45.000 60

1920 x 1080 @ 50i 74.250 28.125 50

1920 x 1080 @ 60i 74.250 33.750 60

e. For factory preset.

Table3: Factory preset

Item Factory Preset Item Factory Preset

Picture mode NATURE OSD language English

Sound mode User Color temperature Standard

Volume 30 Backlight 50

Model No.: LCT-20PSST Version: 1.0

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METHOD OF SOFTWARE UPGRADING

Step of software upgrading are as follows:

1. Using the parallel port wire and DVI transfer to VGA connection wire and then connect them by

an upgrade board.

2. Enter the factory menu, select upgrading item.

3. Connect main board to PC.

4. Operation the vct49xyi_start.exe display the software interface follow as:

Model No.: LCT-20PSST Version: 1.0

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5. Click the “TVT” item:

6. Click the BOOTLOADER button, display the DOS interface, after the interface disappear, click

the BOOTLAODER VERSION, if it value form 0 to 21, connecting is normal.

7. Click the ERASE 16 BIT FLASH, erasure the program. Click the BOOTLAODER VERSION, if

it value form 21 to 1, the program is erasure.

8. After erasure the program, click the black bar,

Model No.: LCT-20PSST Version: 1.0

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Akira LCT-20PSST User manual

Specifications and Main Features

Frequently Asked Questions

User Manual