The EFD-74 is a panel-mounted, high-resolution, multi-color
CRT display unit. It contains a CRT assembly, deflection yoke, video
amplifiers, horizontal and vertical deflection amplifiers, a phosphor
protection circuit, and high-voltage and low-voltage power supplies. Stroke
writing techniques for drawing lines and characters are used to provide sharp
alphanumerics and symbols with greater than normal illumination. The CRT is a
custom designed, high-resolution unit using three in-line guns and a black
matrix shadow mask. The inline guns allow for convergence correction to be
included in the deflection yoke and eliminate the requirement for dynamic
convergence circuits. A multi-bandpass optical filter enhances contrast and
sunlight visibility. The filter has three optical band passes which are
matched to the wavelength of the tube phosphors. A high-efficiency
anti-reflective coating is deposited on the front of the filter. Horizontal
and vertical deflection amplifiers provide the drive currents to the
deflection yoke. The yoke magnetically deflects the electron beam to the
proper position on the active phosphor area. The deflection yoke is designed
to be self-converging, which eliminates the need for added electronic
circuits to adjust convergence. The video and deflection power supplies and
the high-voltage power supply provide the necessary voltages to operate the
EFD-74. The primary power input to the EFD-74 is +28 V dc from the aircraft
power bus. The EFD-74 can be front-mounted with or without a mooring plate or
rear mounted using a mooring plate. The EFD-74 is convection cooled with
forced-air cooling, although not required, but strongly recommended to
improve reliability. The primary requirement for the EFD-74 is to provide the
maximum convective cooling air path for the system during the design of the
aircraft instrument panel area. The EFD-74 should be mounted in the flight
instrument panel under the attitude director indicator where it is close to,
and slightly below, the pilot's line of vision.
Part Number Differences: Part Number | Bezel Color | Deflection Power Supply | Voltage Power Supply | Horizontal and Vertical Deflection |
622-6197-001 | Black | Yes | Yes | Yes |
622-6197-002 | Gray | Yes | Yes | Yes |