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JVC 370 SC, 330, 340 SC service manual Vertical Preamps

Models: 340 SC 370 SC 330

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Vertical Preamps

Chapter 2—Functional Descriptions

Figure 2-13Vertical Deflection Board

Vertical Preamps

The vertical preamps (B, G, and R) each generate a ramp signal with the frequency determined by the incoming signal VERTDR from the Horizontal Deflection Board. The ramps generated in the preamp section have their common amplitude set by the commanded height and are corrected for vertical linearity (linearity is individually adjustable by R211, R311, and R411 and raster height is individually adjusted by R228, R328, and R428). The common raster height is adjusted by a signal sent from the SCB to the VDB via the serial bus. To control height, the operator presses the SIZE button on the remote control, then adjusts height with the up and down arrow keys. The ramp generated by the red preamp is used elsewhere in the VDB for the generation of correction signals.

2-34	Model 330. 340SC, and 370SC Service Manual

Image 46

JVC 370 SC, 330, 340 SC service manual Vertical Preamps

Contents

SERVICE MANUAL DECLARATION OF CONFORMITYHughes-JVC Technology Corporation Model Model 340 SC Model 370 SCManufacturer Hughes-JVC Technology Corporation Confidential and proprietary informationIntroduction Safety InformationSafety Equipment Warnings and CautionsInstallation Safeguards Projector WeightFans Heat SafeguardsLight Safeguards Ultra Violet and Infrared LightUltraviolet radiation, dangerous glare, and high internal gas pressure Ventilation and Foreign Object Retrieval Fluid SafeguardsPower Supply PowerSafety Model 330, 340SC, and 370SC Service ManualSafety Model 330, 340SC, and 370SC Service Manual1.0 Introduction 1.1 Acronyms Used In Manual1.4 Hardware Compatibility 1.2 Safety1.3 Updates Model 330, 340SC and 370SC Service ManualVideo Amplifier Board Contents 2.0 Functional Descriptions2.1 Cover and Base 2.2 External Power Requirements 2.3 Electronics Systems OverviewThe Model 330, 340SC and 370SC Electronics System consists of 2.4 System Power System Power SupplyFigure 2-2 Backplane Status Indicators ∇ Model 330. Model 340SC = +25V/80a Model 370SC = +30V/100a 2. +24V Standby and Arc Lamp power supplies turn on Arc Lamp Ignitor 22-30V depending on projector model High Voltage Power Supply Model 330, 340SC, and 370SC Service Manual High Voltage Power SupplyPower and Control Connector Pins 1,4,5,10 not usedCRT anode voltages are not user controllable. They are fixed at 32KV with a maximum output of 2.1mA total or 0.7mA per CRT. The anode voltage is the primary acceleration voltage for the CRT. Other bias voltages screen grid, G2, and control grid, G1 are used to control the level of beam current. The anode voltage is routed out of the top of the HVPS, into the CRT housing to three 3 bulkhead connectors. From there, the anode wires on the CRTs route the anode voltage directly to the CRT. The anode voltages are overvoltage and overcurrent protected in the event of short circuits or CRT arcing 2.5 Card Cage 340SC 2.6 Circuit BoardsDescription 370SCChapter 2-Functional Descriptions Model 330, 340SC, and 370SC Service Manual2-16 Chapter 2-Functional Description Figure 2-10 Raster Generation Block DiagramModel 330, 340SC and 370SC Service Manual 2-17Raster Timing Generator Board RTG p/n Sync Generator Sync Detector and SelectorSerration and Equalization Lockout Phase Locked LoopVSYNC Detector, Field Separator, and Mux Adjustment Counters Information Serial CommunicationDescription Raster Timing Generator I/O IICCLKHorizontal Deflection Board System Power Supply Interlocks and ProtectionHorizontal Deflection Board P/N 102523 HDB InputsVertical Oscillator Horizontal Power Supply Horizontal Phase Locked LoopHorizontal Centering Geometric Correction Flyback SwitchingOutput Section Information Horizontal Sweep Failure DetectionSerial Communication DescriptionHorizontal Deflection Board I/O Raster Timing Generator Interlocks and Protection Vertical Deflection Board P/N 102521VDBSystem Power Supply InputsVertical raster centering Top and bottom pincushion correction Vertical Preamps Sweep Failure Detection Vertical AmplifiersSide Pincushion and Keystone Correction Horizontal Linearity Correction Top and Bottom Pincushion and Keystone CorrectionSerial Communication Correction AmplifiersRXCORR RYCORR GXCORR GYCORR BXCORR Description General I/OInformation System Controller BoardSystem Controller Board Outputs Output Interlocks and ShutdownsInput InternalChapter 2-Functional Descriptions Model 330, 340SC and 370SC Service Manual2-42 Video Processor Board P/N 104672 VPB Decoder SG Sync Strip Video/Sync MuxV & H Sync Strip B, G, and R Brightness and Contrast AmplifiersSwitch Logic and Video Enable On-Screen SwitchGamma Correction RGB Sensitivity and Threshold Amplifier Serial Communication ILA BiasDynamic Focus Amplifier InformationInput General I/OSystem Controller Board DescriptionDescription System Controller BoardOutputs Raster Timing GeneratorVertical Deflection Board Description Image Light AmplifiersOutputs DecoderInterlocks and Protection High Voltage Power SupplySystem Power Supply OutputsOutput Video Amplifier Board P/N 103567 or 103774 VABInternal Video Signal Failure DetectionBeam Current Sense DC RestoreEnable Circuit Arc ProtectionThis section provides a comprehensive description of the inputs to and outputs from the VAB. The I/O description are arranged by the source/destination of the signal and so the assemblies communicated with are used as the primary heading of each group of signals and then are further subdivided into inputs and outputs. In each case, the signals direction is noted, with input referring to an input to the VAB, and output to an output from the VAB e.g. under Video Processor Board Input CLAMP refers to the signal CLAMP that is an input to the VAB from the Video Processor Board. When test points are provided for the I/O they are noted General I/OVideo Processor Board Inputs System Controller Board P/N 104668 SCBSystem Power Supply DescriptionGeneral Functional Description Page Working and Compressed Memory Expanded MemoryCorrection Address Generator DACsOverlay Memory Overlay Address GeneratorRS232 Interface Overlay InterfaceLED Display Buffers and Logic IR InterfaceThere are three 3 ports for receiving IR radiation. One 1 is located on the front of the projector just above the Green projection lens and the other two 2 are located on the rear panel. One of the receivers on the rear panel is located next to the LED display and, like the front receiver, is used for directly receiving IR radiation. The other rear-mounted receiver is used for connecting an IR repeater, which is an optional device that allows the user to control the projector from up to 150 feet away IIC InterfaceSerial Interface General I/OInput Video Processor BoardDescription DescriptionInput Raster Timing GeneratorDescription DescriptionInput Vertical Deflection BoardDescription DescriptionHorizontal Deflection Board Backplane Backplane Board p/n2.7 Optical Section CRT AssemblyImage Light Amplifier ILA Assembly Relay Lenslight. The vertically polarized light then passes through the prism to the projector lens. The ILA assembly combines the input signal from the CRT with the high intensity light from the arc lamp. Thus, the brightness of the screen image does not depend on the brightness of the CRT but on the light from the xenon arc lamp. A more detailed explanation of the ILA assembly is in Section 2.8 at the end of this chapter Intensity Light=Bright Image CRT ImageCombined Image and High ScreenPrism Arc Lamp AssemblyProjection Lens 2.8 Image Light Amplifier Optical SubassembliesFigure 2-20 The Hughes-JVC Image Light Amplifier Figure 2-21 Simplified illustration of the Series 300 Projector optical path Contents 3.0 Service Adjustments3.1 Service Cover-Off Power-On Sequence Chapter 3---Service AdjustmentsMain AC Circuit Breaker 3.2 CRT Yoke Rotation 7. View R 3.3 Vertical Size Tracking 3.4 Vertical Linearity Tracking 3.5 Horizontal Size Tracking 3.6 ILA Bias Settings Note On Super Contrast Ila Assemblies3.7 CRT Mechanical Focus The lower-left rod adjusts the CRT to ILA distance z- axis 2. Increase Size to 100% horizontal and vertical 3.8 Electronic Focus 3.9 Jumper Settings Front/Rear JumpersR E A R p ro jectio n F R O N T p ro jectio nJ200 J201 J600 J400 Inverted Vertical JumpersJ300 J301 J500 J501 J601G2 Setting 3.10 G2 AdjustmentSensitivity/Threshold Offset To set G2 1. Cut off R and B and view G 3.11 Arc Lamp Alignment and Focus Model 330 Arc Lamp Alignment and FocusTo refocus the Model 330 Arc Lamp Y-Axis Plate Model 340SC and 370SC Arc Lamp Alignment and FocusX-Axis Plate Z-Axis Screwplate 3.12 Arc Lamp Current Adjustment Figure 3-9. Model 340SC and 370SC Arc Lamp Adjustments2. Measure the number of millivolts between pins 3 and 4 on SPS J505 Model 330, 340SC, 370SC Service Manual Chapter 3---Service Adjustments3-23 Contents 4.0 Maintenance Remove/Replace4.1 Introduction Model 330, 340SC, and 370SC Service ManualWARNING!!! Disconnect AC power from the projector before performing any removal and replacement proceduresModel 330, 340SC, and 370SC Service Manual Chapter 4-MaintenanceFigure 4-1 Major components of the Model 330 Projector Model 330. 340SC, 370SC Service Manual Chapter 4-MaintenanceFigure 4-2 Major components of the Model 340SC and 370SC Projectors 4.2 Projector Covers 4.3 Ventilation Filters4.4 Arc Lamp Assembly Model 330 Ignitor and Arc Lamp Assembly P/N 900611S RemovalJ503 and J504 Ignitor Assembly Ignitor Wire ColorWire goes to Location onJ503 J504 J505 Interlock Switch Lamp Current Adjust Interlock Switch Fan Connector Circuit BreakerStart Capacitor Squirrel Cage Fan Cable Collimating Condensing Lens Adjustment 3-mm Set Screw Mounting Screws4.5 System Power Supply AC Power Terminal Block Ground Main AC Circuit Breaker Mounting screws under lip4.6 Electronics Module 11. Replace the module in the reverse order 4.7 Cathode Ray Tube CRT Model 330 CRT Removal5. Remove the video amplifier board from the CRT Assembly Section Chapter 4-Maintenance Figure 4-10 Model 340SC and 370SC CRT AssemblyFigure 4-11 CRT Z-Axis Focus Adjustment Rods circled Model 330, 340SC, and 370SC Service ManualModel 340SC and 370SC CRT Removal 4.8 Video Amplifier Board VABTo remove a VAB see Figure 4-9 or Figure 4.9 CRT Yoke To remove the CRT yoke see Figure 4-9 or Figure4.10 High Voltage Power Supply HVPS 4.11 Card Cage Printed Circuit Boards 4.12 Image Light Amplifier Assembly 4.13 Projection Lens Lens Locking RodsTable 4-2 for reference to part numbers, if necessary Chapter 4-MaintenanceModel 330. 340SC, 370SC Service Manual 4-24Lens Throw 4.14 SCB Socket Battery ReplacementCAUTION! Never place the socket battery on a metal Lens Part Number or DesignationCAUTION! Never place the socket battery on Quantity 4.15 Recommended SparesDescription 340SC5.1 General Information 5.0 TroubleshootingContents Page 5.2 Power-On Codes Code Second SetDescription Meaning 5.3 Break PointsCode DescriptionCode Resetting the ProjectorBreak Trap Data from the Diagnostics Menu DescriptionChapter 5---Troubleshooting 5.4 Main Menu StructureVersion 5.1.0 Software Menu Diagram Model 330, 340SC, and 370SC Service ManualService Problem andPossible Solution Symptom toService Problem andPossible Solution Symptom toService Problem andPossible Solution Symptom toService Problem andPossible Solution Symptom toService Problem andPossible Solution Symptom toService Problem andPossible Solution Symptom toIntermittent Glossary of Terms Cold Mirror Test pattern of black-to-white gradation bars. The more levels Intensity Lumen Raster Phase adjustmentResolution RetraceScan temporarily with the Executive I/R remote See Arc LampModel 330, 340SC, and 370SC Service Manual Glossary