Service manual

L9CMonitor
L9C service manual Page20 of 48
- Techview Confidential -
4. THEORY OF OPERATION
This section describes the function of the LCD monitor per functional block.
L9EA monitor includes MB Board (including audio board function inside), power board and button board.
4.1 MB BOARD
The MB board is a two-layer, single-landed design with ground and ground planes provided.
The VGA cable is a signal cable that contains video signal, sync signal and DDC signal from PC VGA
adapter This system board consists of 3 functional areas : flat panel controller, Micro controller and
audio controller.
4.1.1 Flat panel controller… Mstar TSU16AK (U3)
The heart of the system board is Mstar TSU16AK. The TSU16AK is a graphics processing IC for
LCD monitor. It provides some control functions required for LCD panel. On-chip functions include a
high-speed triple-ADC , PLL, high sacling engine and OSD controller.
a) Clock Generation :
Crystal Input Clock (XTALI and XTAL). This is the input pair to an internal crystal oscillator and
corresponding logic. A 14.318 MHz crystal is recommended.
b) Hardware Reset ( Pin 32 )
Hardware Reset signal is generated by MTV312 (U5/Pin 26).It assert a reset signal at least 1 ms.
c) Analog to Digital Converter
The TSU16AK chip has three ADC's (analog-to-digital converters), one for each color (red,
green and blue) . The analog RGB signals are connected to TSU16AK as described below
Pin Name Pin Numbe
r
Red + 63
Red - 62
Green + 60
Green - 59
Blue + 58
Blue - 57