Akai LTA-26C904, Service Manual

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4. Introduction of printed board module
Akai LCD TV with LS01 is made up of power board, side AV board, remote control
reception board, key board, and mainboard. The table below is the introduction of the function
of all printed board modules.
No.
Designation of
module
Function description
1
Mainboard
module
Mainboard module is the core part of LCD TV signal processing. Under
the control of the system control circuit, It undertakes the task of
converting the external input signal into the unified digital signal that the
LCD screen could identify. Mainboard controls the whole machine
through MCU bus, decode VIDEO signal, controls the image analog
quantity (brightness, contrast, chroma, hue, definition etc), adjusts white
balance, generates OSD, de-interlaces signal, converts signal frequency,
and finishes signal A/D and D/A conversion, video enhancement, LVDS
signal coding and output; it has Scart interface, “S” terminal, AV terminal,
Ypbpr, HDMI and PC interface, Tuner input, sound demodulation, sound
effect treatment, sound power amplifier, and online upgrade of program.
2
Remote
reception board
module
The remote reception board module is constituted by an indicator-light
and a remote reception-head. Customer could manipulate the LCD TV by
using remote controller very conveniently. By the color of the indicator
light, the operation mode of the LCD TV could be judged (red is standby,
green is power on).
3
Built-in power
board module Convert the 100V
～
240V AC into DC, output have +24v, +12V, +5V, and
the +5V_stb in standby state.
4
Keyboard
module
Keyboard module has 7 function keys (program increase/decrease,
volume increase/decrease, AV/TV switch, menu key, on/standby control),
customer could use the key of the machine to manipulate the LCD TV.
5
LCD screen
module
LCD screen has built-in inverter that convert DC into high voltage AC
signal to ignite the backlight CCFL (Cold Cath
ode Fluorescent Light); the
LCD screen process the video signal from signal board and reappear.
6 Side AV board Side AV board is used for earphone output.