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Chapter 2---System Description

Model 250 Service Manual 2-5

Relay Lens Assemblies (3)

There are three Relay Lenses, one for each color. The Relay Lens focuses the

image light from the CRT onto the photosensitive layer on the input side of the

ILA

. The Relay Lens is physically connected to the CRT (see Figure 2-2).

Front Projection Lens

The Model 250 comes with a choice of four standard lenses. These include a

motorized Zoom Lens or one of three Fixed Lenses. All Projection Lenses have

motorized focus.

Motorized Zoom 2:1-4:1

Fixed Lens

0.96

1.5:1

5.6:1

2.4

Electronic Section

The electronics section consists of the Input Cards (VICs), the Printed Circuit

Boards (PCBs), and the CRT/Yoke assemblies.

Input Cards (VICs)

There are two standard Input Cards and four optional VICs. The Input Cards are

the first stop for the source input signal. They provide the RGB and Sync

interface for the projector. All VICs are IIC controlled.

Standard VICs:

Standard RGBHV VIC - The RGBHV VIC is a straight feed-through with

an IIC selection control.

Graphic Enhancer Plus VIC - The Graphics Enhancer Plus VIC is exactly

the same as the RGBHV VIC except for a Menu controlled adjustment for

black on white graphics and text display

Optional VICs:

YPbPr VIC - Composite Video Decoding for YPbPr

Quad Standard Decoder VIC - Composite Video Decoding (NTSC,

SECAM, and PAL)

Quad Standard Decoder and Line Doubler VIC - Composite Video

Decoding (NTSC, SECAM, and PAL) with Line Doubling

Four-Input RGBHV - Four- Input RGBHV with IIC controlled Mux

(switcher)

JVC 250 User Manual

Questions and Answers: