Akai LTA-15N602M Schematic
LTA15N602M
LTA15N680HCP
LTA15N686HCP
LTA19N508HCP
LTA22N680HCP
LTA22N686HCP
LCD TELEVISION
SERVICE MANUAL
CHASSIS LS03
Please read this manual carefully before service.
1
CONTENTS
PartⅠ:Specification, feature and Composition ……………………………………3
PartⅡ: Function introduction about the main integrated circuit ………………..6
PartⅢ: Signal Processing Flow chart ….………………………………………….17
PartⅣ: Typical troubleshooting processing flowchart …………………………..22
Annex: Circuit schematic diagram
2
PartⅠ: Specification , feature and Composition
Ⅰ. Main feature
1、Radio frequency input
It can receive CATV signal.
2、AV input
Convenient for watching a DVD player,VCR,pickup camera or other playback
devices.
3、Scart input
Convenient of receiving a high quality component signal from a DVD player.
4、YPbPr input
Capable of receiving the high definition YPbPr signal in 480i, 480P, 576i, 576P, 720P,
1080i, and 1080P formats.
5、Scart output
6、VGA input
a. Convenient to connect with a host computer.
b. Use as a data display terminal.
c. Connect the 3.5mm(diameter)audio jack to your computer’s soundcard to listen to
stereo sound transmitted from your home computer.
7、Program & child lock function
Capable of locking any program of the TV and the function button of the front panel.
8、Timer function
9、Blue background with noise reduction
In AV、Scart and YPbPr modes, screen displays soft blue background , if there is no
signal input.
10、 Multi Language on-screen display menu
Text and graphical user interface makes the menu operation user-friendly.
11、 Power energy Saving mode(power management mode)
When used as PC display terminal without PC signal output, the LCD TV will
automatically power off within 30 Seconds and enter Power Energy Saving Mode. It
will automatically startup again when it receives a signal from the PC.To start the TV
manually with no signal press the number buttons or【 】/【P+】/【P-】 on the remote
control.
12、Plug-and-play
No additional software is needed when the product is used as computer
terminal display.
13、Automatic picture’s quality adjustment
14、No flicker, no radiation, greenness and health
15、Auto on as time is set
16、Zoom mode（for19”,22”）
Full-screen 、16:9、cinema、Subtitle
17、Legerity, convenient, low power consumption
18、Picture quality enhancement function
Dynamic skin color correct: improve distort color in picture, make it near to real
3
color.
Black level extension: darken the large part of black section to enhance pictures
contrast in the dim background Color edge adjustment: increase the steep of color
signal edge, make the edge of color transition more clearly. Brightness edge
adjustment: increase edge gradient of brightness signal, make the edge of picture
more clearer
19、Super definition display panel
20、Dynamic comb filter
21、Headphones output(not conclude 02 series)
22、8 page teletext
Ⅱ. Circuit composition of the TV
The Europe LS03 chassis LCD TV is composed of regulating voltage Circuit, inverter
Circuit, RF circuit, video enhancement circuit, video Processing circuit, Power
amplifier circuit, VGA circuit, system control circuit and key control circuit. The
block diagram of circuit composition is below:
Ⅲ. PCB assembly introduction
All the Signal Processing are in Main board.
1、 Main board assembly
Main board Module is the main part of Signal Processing in LCD TV. The input
signal is converted into uniform digital signal which can be identified by TFT under
the control of system control circuit.
2、 Key board assembly
It is composed of 7 function keys. the user can operate the LCD TV conveniently by
4
using this assembly.
3、 Remote control receiving board assembly
It is composed of a work indicator light and a remote receive head. The user use the
remote control box by this module can operate the LCD TV conveniently and know
the LCD TV work condition.
4、 Earphone output board assembly(not conclude 02 series)
It is composed of a earphone outlet, user can Listen by earphoneconveniently.
5、 Inverter board assembly(include inverter circuit)
The function of the inverter is supply power to light tube in TFT , and lighten the back
lamp Unit of TFT module, so the user can see the image on TFT.
5
PartⅡ: Function introduction about the main integrated
circuit
Ⅰ. Main ICs and components
Serial
number
1 U4 MP1430DN-LF-Z Liner voltage IC
2 U8 PI5V330SQEX Video switch
3 U9 24LC21AT/SN EEPROM(save display
4 U23 24LC32AT/SN EEPROM（save user
5 U11 STV-8217 Audio processor
6 U15 TDA1517P Audio power amplifier
7 U19 TDA9886TS/V4 single and
8 U17 TDA5-E2I21RW2 RF tuner
9 U22 MST718BE-LF Processor with Video
Ⅱ. The function introduction of main IC
1 The MST718BE is a high quality ASIC for NTSC/PAL/SECAM LCD-TV
application. It receives analog NTSC/PAL/SECAM CVBS and S-Video inputs from
TV tuners, DVD or VCR sources, including weak and distorted signals, as well as
analog RGB input from GPS systems. Automatic gain control (AGC) and 10-bit
3-channel A/D converters provide high resolution video quantization. With automatic
video source and mode detection,users can easily switch and adjust variety of signal
sources. Multiple internal adaptive PLLs precisely extract pixel clock from video
source and perform sharp color demodulation. Built-in line-buffer supports adaptive
2-D comb-filter, 2-D sharpening, and synchronization stabler in a condense manner.
The output format of MST718BE supports 8-bit TTL or LVDS digital TFT-LCD
modules.
MST518 FEATURES:
Video Decoder
· Supports NTSC, PAL and SECAM video input formats
·2D NTSC and PAL comb-filter for Y/C separation of CVBS input
·Multiple CVBS and S-video inputs Supports Closed-caption and V-chip
·Supports Teletext 1.5
·ACC, AGC, and DCGC (Digital Chroma GainControl)
Analog Input
Name model Main function
parameter information)
control information）
multistandard
alignment-free
IF-PLL demodulators
Decoder
6
·Supports RGB input format from PC,camcorders and GPS
·Supports YCbCr inputs from conventional videosource and HDTV
·Supports SCART – RGB + Fast Blank
·Supports video input 480i, 480p, 576i, 576p,720p, 1080i; RGB input resolution in
640x480,800x480, 800x600, 1024x768, and 1280x1024(SXGA)
·3-channel low-power 10-bit ADCs integration for YCbCr and RGB
·Supports RGB composite sync input (CSYNC),SOY, SOG, HSYNC, and VSYNC
·On-chip clock synthesizer and PLL
·Auto-position adjustment, auto-phase adjustment, auto-gain adjustment, and
auto-mode detection
Color Engine
·Brightness, contrast, saturation, and hue adjustment
·9-tap programmable multi-purpose FIR (Finite Impulse Response) filter
·Differential 3-band peaking engine
·Vertical peaking
·Spatial noise reduction
·Luminance Transient Improvement (LTI)
·Chrominance Transient Improvement (CTI)
·Black Level Extension (BLE)
·White Level Extension (WLE)
·Favor Color Compensation (FCC)
·3-channel gamma curve adjustment
·Independent 6 color of saturation, hue, and brightness control
Scaling Engine/Panel Interface
·Supports digital panels up to 1366x768, and 1440x900
·Supports single/dual 8-bit LVDS panel outputs
·Supports 8-bit TTL panel output
·Supports various displaying modes
·Supports horizontal panorama scaling
Miscellaneous
·Built-in MCU
·3-wire serial bus interface for configuration setup
·Built-in step-down PWM circuits for input 2.5V
·Built-in internal OSD with 512 programmable fonts, 1、2 or 4 bit per pixel
color,16-color palettes, and 12-bit color resolution
·Supports external OSD
·Support CVBS out
·Spread spectrum clocks
·Optional 3.3V / 5V output pads with programmable driving current
·128-pin PQFP package
MST718 pin function:
Analog Interface
Pin Name Pin Type Function Pin
7
VMID
VCLAMP
REFM
REFP
Mid-Scale Voltage Bypass 2
CVBS/YC Mode Clamp Voltage Bypass 3
Internal ADC Bottom De-coupling Pin 4
Internal ADC Top De-coupling Pin 5
PRINP Analog Input Analog Pr Input of HDTV 7
PRINM Analog Input
Reference Ground for Analog Pr Input of
HDTV
8
PBINP Analog Input Analog Pb Input of HDTV 9
PBINM Analog Input
Reference Ground for Analog Pb Input of
HDTV
10
SOY Analog Input Sync-on-Y slicer input 11
YINP Analog Input Analog Y Input of HDTV 12
YINM Analog Input
Reference Ground for Analog Y Input of
HDTV
13
BINP Analog Input Analog B Input of VGA 14
BINM Analog Input
Reference Ground for Analog B Input of
VGA
15
SOGIN Analog Input Sync-on-Green slicer input 16
GINP Analog Input Analog G Input of VGA 17
GINM Analog Input
Reference Ground for Analog G Input of
VGA
18
RINP Analog Input Analog R Input of VGA 19
RINM Analog Input
C1INP Analog Input Analog Chroma Input for TV S-Video1 /
Reference Ground for Analog R Input of
VGA
20
22
Analog Composite Input of TV CVBS4
C1INM Analog Input Reference Ground for Analog Chroma Input
23
of TV S-Video1 / Analog Composite Input of
TV CVBS4
YS1INP Analog Input Analog Luma Input of TV S-Video1 / Analog
24
Composite Input of TV CVBS3
YS1INM Analog Input Reference Ground for Analog Luma Input of
25
TV S-Video1 / Analog Composite Input of
TV CVBS3
C2INP Analog Input Analog Chroma Input for TV S-Video2 26
C2INM Analog Input
Reference Ground for Analog Chroma Input
of TV S-Video2
27
YS2INP Analog Input Analog Luma Input of TV S-Video2 28
YS2INM Analog Input
Reference Ground for Analog Luma Input of
TV S-Video2
29
CVBS1P Analog Input Analog Composite Input for TV CVBS1 30
CVBS1M Analog Input Reference Ground for Analog Composite 31
8
Input of TV CVBS1
CVBS2P Analog Input Analog Composite Input for TV CVBS2 32
CVBS2M Analog Input
Reference Ground for Analog Composite
Input of TV CVBS2
33
Pin Name Pin Type Function Pin
VREXT_CDAC Analog Input
HSYNCIN1 Schmitt Trigger
Input w/
Reference Current Generator, 820 ohm
to Ground
HSYNC / Composite Sync for VGA
Input 1
116
125
5V-tolerant
VSYNCIN1 Schmitt Trigger
VSYNC for VGA Input 1 124
Input w/
5V-tolerant
HSYNCIN2 Schmitt Trigger
Input w/
HSYNC / Composite Sync for VGA
Input 2
123
5V-tolerant
VSYNCIN2 Schmitt Trigger
VSYNC for VGA Input 2 122
Input w/
5V-tolerant
Digital Panel Output Interface
Pin Name
Pin
Type
Function Pin
CLKO Output Display Clock Output 77
DEO Output Display Enable Output 78
VSYNCO Output Vertical Sync Output 79
HSYNCO Output Horizontal Sync Output 80
BOUT[7]/LVB
0M
BOUT[6]/LVB
0P
BOUT[5]/LVB
1M
BOUT[4]/LVB
1P
BOUT[3]/LVB
2M
BOUT[2]/LVB
2P
BOUT[1]/LVB
CKM
Output Blue channel Output [7] / LVDS B-Link Channel
0 Negative Differential Data Output
Output Blue channel Output [6] / LVDS B-Link Channel
0 Positive Differential Data Output
Output Blue channel Output [5] / LVDS B-Link Channel
1 Negative Differential Data Output
Output Blue channel Output [4] / LVDS B-Link Channel
1 Positive Differential Data Output
Output Blue channel Output [3] / LVDS B-Link Channel
2 Negative Differential Data Output
Output Blue channel Output [2] / LVDS B-Link Channel
2 Positive Differential Data Output
Output Blue channel Output [1] / LVDS B-Link Negative
Differential Clock Output
108
107
106
105
104
103
102
9
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