Main Board Section - LG 42PJ350 Training Manual

MAIN BOARD SECTION

MAIN BOARD SECTION
The following section gives detailed information about the Main board. This board contains the
Microprocessor, Audio section, video section and all input, outputs. It also receives all input
signals and processes them to be delivered to the Control board via the LVDS cable. The main
tuner (Silicon Tuner using discreet components) which provides VSB (NTSC), 8VSB (Over the Air
Digital Broadcast) and QAM (Cable Digital) is located on the main board. This board is also where
the television's software upgrades are accomplished through the USB input.
This board has no mechanical adjustments.
The Main Board Receives its operational voltage from the SMPS:
DURING STAND-BY: From SMPS
• STBY 5V
DURING RUN From SMPS : (STBY 5V remains):
• +5V for Video processing
• 17V for Audio
OUTPUTS:
• Distributes power supply turn on commands to the SMPS.
• Distributes Key 1 and Key 2 to the Front IR Board then to the Front Key Pad.
• Receives Intelligent Sensor data from the Front IR Board (via SCL/SDA).
• Drives front Power LEDs.
• Distributes +3.3V_ST and +3.3V_MST to the Front IR Board.
• Routes 10 bit LVDS video signals to the Control Board.
106 August 2010 42PJ350 Plasma