KDL-40EX645, KDL-46EX641, KDL-46EX645, KDL-50EX645, KDL-55EX645 - Sony TV Service Manual (repair manual). Page 14

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KDL-40EX645/46EX641/46EX645/50EX645/55EX645 5
SECTION 1 - FEATURES AND OVERVIEW
CPU: The CPU internal to the MT5396 processor controls all aspects of 
the television functions. Input from the user along with monitoring of critical 
circuits is also performed by this CPU.
LVDS Transmitter: Integrated into the MT5396 is a Low Voltage Differential 
Signaling (LVDS) transmitter. This circuit converts the 8-bit parallel RGB 
video information into a set of high speed serial lines for noise-free 
transmission to the TCON circuits located internally to the LCD panel.
POWER SUPPLY BOARD
There are 4 different Power Supply boards used in the models in this 
manual. The type of board depends on the size of LCD panel. They are:
 
GL5A for the 40” models
 
GL5B for the 46” models
 
GE50 for the 50” models
 
GE55 for the 55” models
There are 3 distinct sections on the power supply:
Standby Supply: Continuously operational as long as AC power is applied, 
the standby supply generates 3.3V for the circuits requiring power while the 
unit is turned off. An unregulated 19V line is present to provide power to the 
main relay, PFC and main power supply at turn-on.
Main Supply: Once the power supply receives a power-on command from 
the CPU on the Main Board, the main switching supply is turned on to 
provide a regulated 12V source and Audio 12V.
Converter: Generates the B+ and B- voltages for the LED backlights.
IR BOARD
Designated as the H Board, the IR Board contains the power, standby and 
timer LED’s that are located on this board along with the IR remote receiver 
and light level sensor.
SWITCH UNIT
This board contains the power, channel and volume up/down and menu 
buttons. 
OVERALL CIRCUIT DESCRIPTION
The 
“Block Diagram” on page 10
 provides an overview of the AZ3FK 
chassis. The following are descriptions of the boards and their functions.
MAIN BOARD
Common to all models utilizing the AZ3FK chassis, the Main Board (A 
Board) contains most of the video processing circuitry along with all audio 
processing. Control of the television is accomplished via a CPU embedded 
within the MT5396 processor. Below is a list of the key components located 
on the Main Board.
TUNER
The tuner is a combination ATSC/NTSC unit. It can receive traditional 
analog NTSC signals via cable or terrestrial along with ATSC digital signals 
via terrestrial (8VSB) or cable (64 or 256 QAM).
MT5396 PROCESSOR
This IC performs the majority of the necessary audio and video processing 
on the Main Board.
Analog Video Input Switch: All analog video sources are selected and 
A/D converted and scaled (if necessary) to 1920 X 1080p 60HZ resolution.
Digital Audio and Video Decoder: The MPEG2 and Digital Dolby audio 
streams are received from the tuner for decompression. All video sources 
which are not native 1920 X 1080p 60HZ are scaled to this resolution. 
Digital audio content is output to the class D amplifier for processing and 
amplification.
Audio Processing: Analog audio sources are selected and A/D converted 
directly by the MT5396. The audio information is then processed digitally. 
Digital audio from the tuner and HDMI sources is also input and processed. 
Class D amplifier provides the drive for the speakers.
HDMI Input and Switching: The customer can select the HDMI1 through 
HDMI4 input. Each HDMI input contains a dedicated EDI NVM (not shown) 
to provide display information data to any device connected via the HDMI 
inputs.
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