![background image](http://html1.mh-extra.com/html/viewsonic/vx922-1/vx922-1_service-manual_1020055028.webp)
6. THEORY OF OPERATION
This section describes the function of the LCD monitor per functional block.
This monitor includes MB board, power board and button board.
6.1 MB BOARD
The MB board is a two-layer, single-grounded design with ground and internal planes provided. DC power from
the power board enters the board through a 6P connector. The other connector on the board is for the button board.
The VGA cable is a signal cable that carries the video, sync and DDC signals from the PC VGA adapter. This
system board consists of 4 functional areas: flat panel controller, MCU with flash ROM, and power regulators.
6.1.1 Flat panel controller: RTD2523(U7)
The heart of the system board is the Realtek RTD2523. The RTD2523 is a graphics processing IC
designed for LCD monitors. It provides all key IC functions required for LCD displays. On-chip
functions include a high-speed triple-ADC, PLL, high scaling engine and OSD controller.
a)
Clock Generation:
Crystal Input Clock (TCLK and XTAL). This is the input pair to an internal crystal oscillator and
corresponding logic. A 24.576 MHz crystal is recommended.
b)
Analog to Digital Converter:
The RTD2523 chip has three ADCs (analog-to-digital converters), one for each color (red, green and blue).
The analog RGB signals are connected to RTD2523 as described below.
Pin Name
Pin Number
Red +
37
Red -
38
Green +
34
Green -
35
Blue +
30
Blue -
31
c)
OSD: The RTD2523 has a fully programmable, high-quality OSD controller. The on-chip static
RAM (4096 words by 24 bits) stores the cell map and the cell definitions.
25
ViewSonic
Corporation
Co
nfidential
-
Do
Not
Copy
VX922-1
Содержание VX922-1
Страница 40: ...Pattern 5 Pattern6 Pattern 7 Pattern 8 Pattern 9 37 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 57: ...Step 2 Press Write to IC icon 54 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 61: ...Please press 58 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 64: ...Write DDC to IC Step 1 Select 24C02 61 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 66: ...Step 2 Press Write to IC icon 63 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 81: ...1 Display color abnormal 6 Troubleshooting Flow Chart 78 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 83: ...3 Monitor white screen 80 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 84: ...4 Monitor black screen 81 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 85: ...5 Analog input always shows NO SIGNAL 82 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 86: ...6 Digital input always shows NO SIGNAL 83 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 89: ...86 ViewSonic Corporation Confidential Do Not Copy 8 Exploded Diagram and Spare Parts List VX922 1...
Страница 92: ...9 Block Diagram 89 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 93: ...90 ViewSonic Corporation Confidential Do Not Copy VX922 1...
Страница 103: ...Main Board Control Board 100 ViewSonic Corporation Confidential Do Not Copy 11 PCB Layout Diagrams VX922 1...