![background image](http://html1.mh-extra.com/html/viewsonic/optiquest-vs11578/optiquest-vs11578_service-manual_1020499020.webp)
ViewSonic Corporation
Confidential - Do Not Copy
Q19wb-3
1
7
6. THEORY OF OPERATION
This section describes the function of the LCD monitor per functional block.19” monitor includes MB
board (including audio board function inside), inverter board, (including adapter function inside) and button board.
6.1 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.
6.1.1 Flat panel controller…… TSUM16AK-LF-1 (U4)
The heart of the system board is Mstar TSUM16AK-LF-1. The TSUM16AK-LF-1 is a graphics processing IC for
LCD monitor. It provides all key IC control functions required for LCD panel. On-chip functions include a
high-speed triple-ADC , PLL, high sacling engine Micro processor and OSD controller ,manages other devices in
the system such as the keypad, the backlight, LED and audio general purpose input/output pins.
a) Clock Generation :
Crystal Input Clock (XTALI and XTAL). This is the input pair to an internal crystal oscillator andcorresponding
logic. A 14.318 MHz crystal is recommended.
b) Hardware Reset ( Pin 19 )
Hardware Reset signal is generated by TSUM16AK-LF-1 (U4/Pin 19).It assert a reset signal at least 1 ms.
Pin number
Pin name
Pin function
23 GPIO_P00/SAR1
Key-Menu
24 GPIO_P01/SAR2
Key-Sel/Auto
25 GPIO_P02/SAR3
Key-Power
on/off
26 GPIO_P03
Key-Right
27 GPIO_P06
Key-Left
28 GPIO_P07
Key-Down(NC)
29 PWM0/GPIO_P26
Key-Up(NC)
30 GPIO_P13
LED-Green
31 GPIO_P14
LED-Orange
35 GPIO_P16/PWM2
Audio-MUTE(NC)
69 GPIO_P15/PWM0
Audio-Stby-Power
78 PWM2/GPIO_P24
Audio-Volume
21 PWM1/GPIO_P25
Backlight-adi
36 DDCD_SDA
SDA-VGA
(Debug)
37 DDCD_SCL
SCL-VGA
(Debug)
65 DDCA_SDA/RS232_TX
SDA(Debug)
66 DDCA_SCL/RS232_RX
SDA(Debug)
Summary of Contents for Optiquest VS11578
Page 53: ...ViewSonic Corporation Confidential Do Not Copy Q19wb 3 50...
Page 64: ...ViewSonic Corporation Confidential Do Not Copy Q19wb 3 61 11 PCB Layout Diagrams...
Page 65: ...ViewSonic Corporation Confidential Do Not Copy 62 Q19wb 3...
Page 66: ...ViewSonic Corporation Confidential Do Not Copy 63 Q19wb 3...
Page 67: ...ViewSonic Corporation Confidential Do Not Copy 64 Q19wb 3...
Page 68: ...ViewSonic Corporation Confidential Do Not Copy 65 Q19wb 3...
Page 69: ...ViewSonic Corporation Confidential Do Not Copy 66 Q19wb 3...