Hughes JVC Projector 250 Sc Service Manual
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Chapter 2---System Description 2-4 Model 250 Service Manual ! Condensing Lenses (2) - The Primary Condensing Lens collects all the light from the Light Pipe and begins to bend the light rays into a straight path. The Secondary Condensing Lens works with the Primary Condensing Lens to collimate or “straighten” the light path before it enters the Dichroic Beamsplitter Assembly. ! UV Filter - The UV Filter removes much of the unwanted ultravioltet light from the white light of the Arc Lamp. ! Dichroic...
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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....
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Chapter 2---System Description 2-6 Model 250 Service Manual Printed Circuit Boards (PCB) The Model 250 Projector has eight main PCBs: ! System Controller PCB - System Controller PCB controls much of the electronics system. It uses digital and analog circuitry to generate Menu and internal pattern overlays, and directs convergence correction and shading information. It controls the IIC data bus that sends geometric correction and VIC selection data. The System Controller PCB controls and monitors the...
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Chapter 2---System Description Model 250 Service Manual 2-7 provides an interconnection interface for all the electronic components in the projector. CRT/Yoke Assemblies The CRT/Yoke Assemblies bridge between the Optical and the Electronic sections. The CRTs could be included in the Optical section because they produces the image light transmitted to the ILA ®s, but they are included in the Electronic section because they are the end user for the image signals from the VICs, Video Processor PCB, and...
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Chapter 2---System Description 2-8 Model 250 Service Manual projector. These air-borne particles can land on optics such as the ILA® and cause large diffuse dark areas on the screen. EMI Shield The Model 250 has an EMI (Electro-Magnetic Interference) Shield that traps and collects high frequency noise that is radiated by switching power supplies such as the Arc Lamp Power Supply and the Low Voltage Power Supply. This high frequency noise can interfere with the operation of radios, televisions, and other...
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Chapter 3---Electrical Model 250 Service Manual 3-1 3.0 Electrical Contents 3.1 Safety............................................................................................................ 3-1 3.2 Incoming Power Circuit ............................................................................... 3-2 AC Power Cord .......................................................................................... 3-2 AC Circuit...
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Chapter 3---Electrical 3-2 Model 250 Service Manual Left/Right Orientation: When referring to the left or right in this chapter, it is with reference to standing at the rear of the projector, facing the screen. Connectors on subassemblies and PCBs have tabs that must be released first before pulling on the connector. The proper procedure is to push slightly IN on the connector, then squeeze the tab, then pull the connector out. 3.2. Incoming Power Circuit AC Power Cord The Power Cord performs one...
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Chapter 3---Electrical Model 250 Service Manual 3-3 3.3 Power Supplies All Series 200 projectors including the Model 250 have three power supplies. These include: ! Low Voltage Power Supply ! Arc Lamp Power Supply ! High Voltage Power Supply There is a fourth power supply, the Laser Power Supply, but that power supply is used only for the Igniter Assembly during Arc Lamp lighting. Low Voltage Power Supply (LVPS) LVPS - Main Functions: ! Provides all the low voltages needed by the projector. !...
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Chapter 3---Electrical 3-4 Model 250 Service Manual Figure 3-1 Low Voltage Power Supply I/O Diagram. LVPS - Operation: AC power is delivered to the Low Voltage Power Supply from the AC line filter. The AC is rectified to a DC Voltage, filtered, and goes through a power factor correction circuit to force the current waveform to follow the voltage waveform. The +5.1V Standby is on whenever AC power is connected to the projector and the circuit breaker on the rear panel is in the ON position. When the AC...