Projector Service Manual
Table Of Contents
- DECLARATION OF CONFORMITY
- BZSAFE.PDF
- CH1INTRO.PDF
- CH2SYSDE.PDF
- Functional Descriptions
- Contents
- Cover and Base
- External Power Requirements
- Electronics Systems Overview
- System Power
- Card Cage
- Circuit Boards
- Raster Timing Generator Board (RTG) p/n 100568
- Sync Generator
- Sync Detector and Selector
- Serration and Equalization Lockout
- Phase Locked Loop
- VSYNC Detector, Field Separator, and Mux
- Adjustment Counters
- Serial Communication
- Raster Timing Generator I/O
- Interlocks and Protection
- Horizontal Deflection Board P/N 102523 (HDB)
- Vertical Oscillator
- Horizontal Phase Locked Loop
- Horizontal Centering
- Horizontal Power Supply
- Flyback Switching
- Geometric Correction
- Output Section
- Horizontal Sweep Failure Detection
- Serial Communication
- Horizontal Deflection Board I/O
- Interlocks and Protection
- Vertical Deflection Board P/N 102521(VDB)
- Vertical Preamps
- Vertical Amplifiers
- Sweep Failure Detection
- Side Pincushion and Keystone Correction
- Horizontal Linearity Correction
- Top and Bottom Pincushion and Keystone Correction
- Correction Amplifiers
- Serial Communication
- General I/O
- Interlocks and Shutdowns
- Video Processor Board P/N 104672 (VPB)
- Decoder
- Video/Sync Mux
- V & H Sync Strip
- SG Sync Strip
- B, G, and R Brightness and Contrast Amplifiers
- On-Screen Switch
- Gamma Correction
- Switch Logic and Video Enable
- RGB Sensitivity and Threshold Amplifier
- ILA® Bias
- Dynamic Focus Amplifier
- Serial Communication
- General I/O
- Interlocks and Protection
- Video Amplifier Board P/N 103567 or 103774 (VAB)
- Video Signal
- Failure Detection
- Beam Current Sense
- DC Restore
- Arc Protection
- Blanking
- Enable Circuit
- Focus
- Filament Supply
- General I/O
- System Controller Board P/N 104668 (SCB)
- General Functional Description
- CPU
- Working and Compressed Memory
- Expanded Memory
- Correction Address Generator
- DACs
- DSP
- Overlay Memory
- Overlay Address Generator
- Overlay Interface
- LED Display Buffers and Logic
- RS232 Interface
- IR Interface
- IIC Interface
- Serial Interface
- General I/O
- Backplane Board p/n 100571
- Optical Section
- Image Light Amplifier
- Functional Descriptions
- CH3ADJST.PDF
- CH4MAINT.PDF
- Maintenance Remove/Replace)
- Contents
- Introduction
- Projector Covers
- Ventilation Filters
- Arc Lamp Assembly
- System Power Supply
- Electronics Module
- Cathode Ray Tube (CRT)
- Video Amplifier Board (VAB)
- CRT Yoke
- High Voltage Power Supply (HVPS)
- Card Cage (Printed Circuit Boards)
- Image Light Amplifier Assembly
- Projection Lens
- (SCB) Socket Battery Replacement
- Recommended Spares
- Maintenance Remove/Replace)
- CH5TRBSH.PDF
- HGLOSS.PDF
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Chapter 2—Functional Descriptions
2-76 HJT Model 330, 340SC, and 370SC Service Manual
Optical Subassemblies
Cold Mirror
The Cold Mirror lets most of the infrared light pass through and reflects the rest of
the light toward the prism through an ultraviolet filter/condensing lens, dichroic
mirrors and down-steering mirrors.
The infrared light is absorbed in a series of fan-cooled screens.
CAUTION!
Cold mirrors absorb IR light and can get very
hot!
Ultraviolet Filter and Condensing Lens
The arc lamp light beam reflected off the cold mirror passes through the
Ultraviolet Filter/Condensing Lens that removes most of the Ultraviolet light and
condenses the light beam. Therefore, most of the infrared and ultraviolet light is
filtered out before the beam enters the more sensitive portions of the optics,
leaving only the visible portion. Without these filters, the infrared light would
overheat the prisms and the ILA
®
assemblies, and the ultraviolet light would
damage the ILA
®
assemblies and be hazardous to personnel.
Dichroic Mirrors and Down-Steering Mirrors
The condensed light beam strikes the first dichroic mirror that is designed to pass
red and green light but reflect blue light. The blue light is reflected to a down-
steering mirror which reflects it again directly to the prism in the blue system. The
red and green light travel on to the next dichroic mirror that passes the red light
and reflects the green light to the down-steering mirror and prism in the green
system. The red light travels on to the last Dichroic mirror which reflects the
remaining red light to the last down-steering mirror and prism in the red system.
Each of these three (3) light beams independently combines with the video image
in their own (red, green or blue) color systems at the ILA
®
assemblies as described
above.
CAUTION!
Do not attempt to realign any mirrors. They require
the use of a complex laser beam alignment fixture.
2.8 Image Light Amplifier
A closer examination of the output side of the ILA
®
assembly as illustrated in
Figure 2-20 helps in understanding its operation.
Visible light from the arc lamp passes through dichroic mirror assemblies and is
then reflected into a prism assembly that polarizes the light horizontally. The