China LT-15AMF LCD Schematic

COLOR TFT-LCD TV SERVICE MANUAL

MODEL : LT-15AMF

CAUTION !!

BEFORE SERVICING THE TFT-LCD TV, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

LT-15AMF SERVICE MANUAL

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SAFETY PRECAUTIONS

!! Important Safety Notice !!

Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the Schematic Diagram and Replacement Parts List. It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer.

Leakage Current Hot Check (See below Figure)

Plug the AC cord directly into the AC outlet. Do not use a line Isolation Transformer during this check. Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor between a known good earth ground (Water Pipe, Conduit, etc.) and the exposed metallic parts. Measure the AC voltage across the resistor using AC voltmeter with 1000 ohms/volt or more sensitivity. Reverse plug of the AC cord into the AC outlet and repeat AC voltage measurements for each exposed metallic part. Any voltage measured must not exceed 0.75 volt RMS, which is, corresponds to 0.5mA. In case any measurement is out of the limits specified, there is possibility of shock hazard and the set must be checked and repaired before it is returned to the customer.

Leakage Current Hot Check circuit

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SERVICING PRECAUTIONS

CAUTION!!

Before servicing receivers covered by this service manual, read and follow the SAFETY PRECAUTIONS on page 3 of this publication.

General Servicing Precautions

1.Always unplug the receiver AC power cord from AC power source before;

ⓐRemoving or reinstalling any component, circuit board module or any other receiver assembly. ⓑDisconnecting or reconnecting any receiver electrical plug or other electrical connection. ⓒConnecting a test substitute in parallel with an electrolytic capacitor in the receiver.

CAUTION!! A wrong part substitution or incorrect polarity installation of electrolytic capacitors

may result in an explosion harzard.

2.Do not spray chemicals on or near this receiver or any of its assemblies.

3.Do not defect any plug/socket voltage interlocks with which receivers covered by this service manual might be equipped.

4.Always connect the test receiver ground lead to the receiver chassis ground before connecting the test receiver positive lead. Always remove the test receiver ground lead last.

5.Do not connect the test fixture ground strap to power supply heatsink in this receiver

Electrostatically Sensitive(ES) Devices

Some semiconductor(solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive(ES) Device.Examples

Circuit Board Foil Repair

Excessive heat applied to the copper foil of any printed circuit board will weaken the adhesive that bonds the foil to the circuit board causing the foil th separate from or “lift-off” the board. The following guidelines and procedures should be flollowed whenever this condition is encountered.

At IC Connections

To repair a defective copper pattern at IC connections use the following procedure to install a jumper wire on the copper pattern side of the circuit board.(Use this technique only on IC connections.)

1.Carefully remove the damaged copper pattern with a sharp knife.(Remove only as much copper as absolutely necessary.)

2.Carefully scratch away the solder resist and acrylic coating(if used) from the end of the remaining coopper pattern.

3.Bend a small “U” in one end of a small guage jumper wire and carefully crimp it around the IC pin.

4.Route the jumper wire along the path of the out-away copper pattern and let it overlap the previously scraped end of the good copper pattern. Solder the overlapped area and clip off any excess jumper wire.

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CONTENTS

Safety precautions ----------------------------------------------------------- 2

Servicing precautions ------------------------------------------------------- 3

Contents ------------------------------------------------------------------------- 4

Specifications ----------------------------------------------------------------- 5

Location of control ---------------------------------------------------------- 8

Disassembly procedure ---------------------------------------------------- 11

Mechanical exploded view with part list ----------------------------- 20

Circuit descriptions --------------------------------------------------------- 21

Trouble shooting ------------------------------------------------------------- 35

Adjustment instruction with SVC mode ------------------------------ 38

Inspection instruction ------------------------------------------------------ 39

PCB Layout --------------------------------------------------------------------- 40

Part appearance -------------------------------------------------------------- 45

Packing instruction ---------------------------------------------------------- 47

Replacement Parts List ---------------------------------------------------- 48

Block diagram ---------------------------------------------------------------- 54

Connection diagram -------------------------------------------------------- 55

Schemetic diagram --------------------------------------------------------- 56

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SPECIFICATIONS

Note: Specifications and others are subject to change without notice for improvement.

1.Scope.

This document is the specification of 15” TFT-LCD Color TV.

2.Power

1) Power requirement DC 12V / 3A

2)AC / DC Adapter.

Input Frequency : 50/60㎐ ±3㎐ Input Voltage : AC 100V ～ AC 230V (±10%)

Output Voltage : DC 12V

3)Power cord Use UL listed and CSA certified detachable power cord type ;SVT, 3-conductors, 18AWG For AC 120V area. Use VDE listed detachable power cord type ;HO5VV-F, 3-conductors,

18AWG for AC 220～240V area.

3.Tuning system

FVS 100

4.Sound output

1W+1Wrms Stereo (Max)

5.Antenna input impedance

VHF / UHF at 75ohm

6.OSD Type (On Screen Display)

Windows type (Center)

7.External in/output

DC Power in, PC/DTV in, PC Audio in, COMPONENT, Head Phone out, S-Video in, A/V in, ANT in.

Audio In : 0.4Vrms, over 10KΩ Video In : 1Vp-p, over 75Ω PC/DTV In: 0.7Vp, over 75Ω

8.Function

CATV/Hyper band Auto Program Manual Program Auto Sleep Quick view PSM(Picture Status memory) SSM(Sound Status memory)

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9.Receiving RF TV system

Model System 1 PAL-B 2 PAL-G 3 PAL-I, I /I 4 PAL-D 5 PAL-K 6 SECAM-B 7 SECAM-G 8 SECAM-D 9 SECAM-K

10 SECAM-K1 11 SECAM-I (6.0) 12 NTSC-3.58 / 4.5 13 NTSC-3.58 / 5.5 14 NTSC-3.58 / 6.0 15 NTSC-3.58 / 6.5 16 NTSC-3.58 / 4.5(5.0) 17 NTSC-4.43 / 5.5 18 NTSC-4.43 / 6.0 19 NTSC-4.43 / 6.5 20 PAL 5.5 / 60Hz 21 PAL 6.0 / 60Hz 22 PAL 6.5 / 60Hz 23 SECAM 5.5 / 60Hz 24 SECAM 6.0 / 60Hz 25 SECAM 6.5 / 60Hz 26 SECAM L / L'

TOTAL SYSTEM 8

SPECIFICATIONS

LT-15AMF / /

X// X// X// X// X// X// X// X// X// X//

X// O// O// O// O// O// O// O// O//

X//

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SPECIFICATIONS

10. PC Mode Scan Frequency & Timing

1)Scan Freq : H: 31 ～ 56 kHz / V : 56 ～ 85㎐

2)Preset Timing Chart

Mode Resolution H-Freq(Khz) V-Freq(Khz)

VGA

SVGA

XGA

DTV (PC)

640x480 640x480 720x400 800x600 800x600 800x600

800x600 1024x768 1024x768 1024x768 720x480p 720x576p

1280x720p

1280x720p 1920x1080i 1920x1080i

37.9KHz

37.5KHz

31.5KHz

35.1KHz

37.9KHz

48.1KHz

46.9KHz

48.4Khz

56.5Khz

60.0Khz

31.5Khz

31.2Khz

45.0Khz

37.5Khz

33.7Khz

28.1Khz

72Hz 75Hz 70Hz 56Hz 60Hz 72Hz 75Hz 60Hz 70Hz 75Hz 60Hz 50Hz 60Hz 50Hz 60Hz 50Hz

Note!! :

ⓐ If the set is cold, there may be a small “flicker” when the set is switched on. This is

Normal, there is nothing wrong with the set.

ⓑ if possible, use the VESA 1024x768 PC video mode to obtain the best image quality for

your LCD TV. If used under the other resolutions, some scaled or processed pictures may appear on the screen.

will have no impact or effect on the monitor performance.

11. TFT – LCD Panel Character

1) Feature

Size :15" Diagonal (38Cm) LCD Type :Color Active Matrix TFT Pixel Pitch :0.297 mm(H) x 0.297 mm(V) Pixel Format :1024x768 Pixels, RGB Stripe Active Video Area :304.1mm(H) x 228.1mm(V) Surface treatment :Haze 25, Anti-Glare & Hard coating(3H) Response Time(Typ) :25mS(Typ) Viewing Angle<CR≥10> : Hor [Left/Right] Æ 70Deg (Typ) / 70Deg (Typ),

Ver [High(Top)/Low(Bottom)] Æ 60Deg (Typ) / 65Deg (Typ)

Luminance(Typ) : 450 cd/㎡(Typ)

Contrast Ratio(Typ) : 350(Typ) Display Color : 16,2M Color Back Light : 4 CCFL

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LOCATION OF CONTROL

All the function can be controlled with the remote controller. Some functions can also adjusted with the buttons on the controls on the TV front panel.

12-1. Remote controller Note !! : Before you use the remote controller, please install the batteries.

1.POWER:

Turns the TV on from standby or off to standby mode.

2.MUTE:

Turns the sound on and off

3.NUMBER buttons:

Select channel numbers.

4.PSM (Picture Status Memory):

Recalls your preferred picture setting.

5.SSM (Sound Status Memory):

Recalls your preferred sound setting.

6.MENU:

Displays a main menu.

7. ST / SAP:

Selects the MTS-Stereo, Mono and SAP

8.Q.VIEW:

Returns to the previously viewed Programme.

9.TV / AV: Selects TV, COMPONENT,

VIDEO, S-VIDEO, RADIO(Only when the set is Radio On.) or PC mode. / Clears the menu from the screen.

10.CH ▲▼ ( Channel Up/Down):

Selects next channel or a menu item.

11.OK:

ccepts your selection or displays the

current mode.

12.VOL ◀▶ ( Volume Up/Down):

Adjusts the sound level or a menu Setting.

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LOCATION OF CONTROL

12-2. Remote controller Note !! : Before you use the remote controller, please install the batteries.

13.CC

Sets the caption function.

14.MEMORY

Stores or removes the current channel.

15.SLEEP

Sets the sleep timer.

16.PC/*

Selects PC mode directly.

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13. Controller of Panel

< FRONT VIEW>

1). MENU:

Display a menu.

2). + CH - ( Channel Up/Down):

Selects a channel or a menu item.

3). POWER INDICATOR:

Illuminates in red when the TV is in power standby mode. Illuminates green when the TV is switched power on mode. Illuminates blinked when the when the power save mode.(only PC mode.)

4). ON/OFF. Switches TV set on or off.

5). REMOTE CONTROL SENSOR.

Accepts the IR signal of remote controller.

6). + VOL - ( Volume Up / Down)

Adjusts the volume. / Adjusts menu settings.

7). TV/AV:

Selects TV, COMPONENT, VIDEO, S-VIDEO, RADIO(Only when the set is Radio On.) or PC mode. / Clears the menu from the screen.

LOCATION OF CONTROL

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DISASSEMBLY PROCEDURE

14. Deassembly procedure

1).Removal of Stand

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2).Removal Backcover

DISASSEMBLY PROCEDURE

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DISASSEMBLY PROCEDURE

3-1).Removal of Terminal metal plate

3-2).Removal of Terminal metal plate

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DISASSEMBLY PROCEDURE

4).Note on refitting terminal metal plate

5) Removal of metal chassis cover

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DISASSEMBLY PROCEDURE

6-1).Removal of Main PCB

6-2).Removal of Main PCB

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DISASSEMBLY PROCEDURE

7).Removal of Inverter PCB

8)Removal of Control PCB

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DISASSEMBLY PROCEDURE

9-1).Removal of LCD Module chassis

9-2).Removal of LCD Module chassis

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