Hughes JVC 100, Service Manual

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Chapter 2---System Description
2-2 Model 100 Service Manual
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The Power Supply Section consists of three power supplies: the Arc Lamp
Power Supply, the Low Voltage Power Supply and the High Voltage
Power Supply. The Arc Lamp Power Supply supplies constant adjustable
current to the arc lamp. The High Voltage Power Supply drives the CRTs
with anode voltage, G
2
voltage, the focus voltage and the G
1
voltage. The
Low Voltage Power Supply provides the standby voltages and bias voltage
for all the digital and analog circuits. It also supplies the CRT filament
voltage and some supply voltages for the Horizontal Deflection PCB, and
the Video Amp PCBs.
!
The Projector Electronics Section is located mainly in the back half of the
projector. It consists of the Electronics Module that houses 6 of the
electronics printed circuit boards used in the projector, and their associated
cabling. It also contains the Backplane PCB which is used to electrically
interconnect the printed circuit boards, power supplies and other units in
the projector, the Video Amp PCBs and Regulator PCB, and the Video
Input Cards that interface with different kinds of input signals.
2.2 Optical System
The Arc Lamp Module
The Arc Lamp Module includes a 750-Watt Xenon Arc Lamp that is located
directly below the Front Projector Lens in the front of the projector. The Arc
Lamp is driven by the Arc Lamp Power Supply, which sits in the front of the
projector opposite the Arc Lamp Module.
The Illumination Path
The illumination path is a very complex optical system of condensing lenses and
integrator lenses, reflective steering mirrors and Dichroic Filters, polarizing
optics, beamsplitters and combining prisms (see Figure 2-1 for physical layout).
The illumination path actually consists of two sections: the light path and the
image path. The light path begins with a light source, the Arc Lamp, then passes
through Primary Condensing Lens and is reflected off the #1IR Filter/Cold Mirror
where the infrared heat radiation is filtered out.
CAUTION!
The term "cold mirror" is used because the
mirror passes infrared light and its reflection contains only "cold' light that
does not transmit appreciable heat. As a result of the absorption of
infrared heat radiation, "cold" mirrors can get very hot.
From the #1 Cold Mirror the high intensity light passes through the Secondary
Focusing Lens, a UV Filter and into the Integrator, which consists of two “fly’s
eye” integrating lenses. The Primary Condensing Lens collects all the light from