Vector 4 - Page 86

VECTOR 4
TECHNICAL INFORMATION
SECTION IV - OVERVIEW OF THE CRT SYSTEM
Summary: This section discusses the operation of the Video Board and
the internal CRT (uses P31 phosphor). These components have controls
which can be adjusted to promde greater screen clarity. A complete
block diagram for this System is shown in Exhlbll_ll_li
The Video Board receives control signals, data and power from several subsystems.
These subsystems are shown in Exhibit II-14, [I-15 and II-16 *. As can be seen the
TTL Video signal is sent to the POT on the front panel before it is routed to the
Video Board.
The other lines (H and V Synec signals, power lmes) are routed d1rect1y the Video
Board.
A. Operati ¢ the Video Board
The Video Board contains all the circuitry used to control and operate the
internal CRT. The major components include fly-back and drive transformers,
horizontal and vertical frequency oscillator circuits, and numerous variable
resistors which are used for sereen adjustments.
The fly-back transformer develops the voltage necessary to drive (anode voltage)
the electron gun in the CRT. The oscillator circuits generate the sawtooth
waveforms which are used for both vertical and horizontal retrace periods. The
TTL Video signal is processed and used to control the cathode plate in neck of
the CRT. The remainder of the Video Boards circuitry supplements these
groups of circuitry.
The Video Board is mounted under the neck of the CRT. The schematic of this
board is shown in Exhibit VI-8 and a diagram gwmg the locations of the
components along with the various screen adjustments is shown in Exhibit TIII-1
of Part I
* A master wiring diagram showing all the interconnecting lines is shown in
Exhibit VI=9.
09-01-82 7200-0001 IT 4-1