Troubleshooting | JVC 250 specs

Chapter 7---Troubleshooting

Amplifier PCB the /SWEEP_OK becomes the /VA_OK signal and checks the supply voltages such as +15 V, +6.2 V and +80 V. The /VA_OK LED illuminates (see Video Amplifier PCB LED) if the supply voltages are present and the /SWEEP_OK is low. The /VA_OK also goes to the High Voltage Power Supply. On the High Voltage Power Supply, a logical “high” shuts down the high voltage amplifier that generates the Anode, Focus, and G2 voltages. The /VA_OK signal also goes to the Video Processor PCB where a logical “high” shuts down the G2 control voltages.

Yoke Connector Detection

The CRT Protection circuit also ensures that CRT Yoke connectors are properly installed. It does this with the H_LOCK+/- circuit. This series circuit goes from the Horizontal Vertical Deflection PCB to the Scan Reversal PCB, through each CRT Yoke connector, and back to the Horizontal Vertical Deflection PCB. The H_LOCK+ has +15 V applied to it on the Horizontal Vertical Deflection PCB. If all the CRT Yoke connectors are properly installed H-LOCK+ and H_LOCK- will both measure +5 V. If the any one of the connectors is not properly installed, H_LOCK+ will measure +15 V and H_LOCK- will measure 0 V. If H_LOCK- is at 0 V. This shuts down the horizontal amplifier circuit that generates the horizontal deflection waveform.

CRT Beam Current

Another function the CRT Protection circuit performs is to monitor the beam current of each CRT. The Video Amplifier PCB outputs a current sense line (RED, GRN, and BLU BEAM) from each image amplifier circuits. The Video Processor PCB receives these current sense lines and compares them to a reference. If the beam current of any CRT exceeds 250 µA, the Beam current LED illuminates orange, and the Video Processor PCB reduces Contrast. If reducing Contrast does not bring the CRT beam current below 250 µA, the Video Processor PCB reduces the G2 voltage until the beam current drops below the limit.

7-20	Model 250 Service Manual

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JVC 250 service manual Troubleshooting

Contents

Model 250 Projector Declaration of Conformity Manufacturer Hughes JVC Table of Contents Parts TroubleshootingSoftware and Protocol Contents Safety Updates Acronyms Used Secam Contents Introduction Electrical Section Incoming Power CircuitPower Supplies Arc Lamp Module Igniter AssemblyOptical Section Optical Path ILA s Image Light Amplifier CRTs Front Projection Lens Electronic SectionRelay Lens Assemblies Input Cards VICs Printed Circuit Boards PCB Miscellaneous Items EMI Shield System Description Safety Electrical AC Circuit Breaker Incoming Power CircuitAC Power Cord AC EMI Filter Lvps Main Functions Power SuppliesLow Voltage Power Supply Lvps Lvps Inputs 1Low Voltage Power Supply I/O Diagram Lvps Operation Lvps Remove and Replace Arc Lamp Power Supply AlpsLvps Service Adjustments Alps Main Functions Alps Inputs Alps Outputs 2Arc Lamp Power Supply signals and voltages Alps Operation Alps Service Adjustments Alps Remove and Replace High Voltage Power Supply Hvps Hvps Main Functions Hvps Inputs Hvps Outputs Hvps Service Adjustments Hvps Operation 5High Voltage Power Supply cover Hvps Remove and Replace PIN # Electrical Igniter Assembly Outputs Igniter AssemblyIgniter Assembly Inputs Igniter Assembly Operation Igniter Assembly Service Adjustments Igniter Assembly Remove and Replace Electrical Optical Arc Lamp Main Functions Arc Lamp Service AdjustmentsArc Lamp Arc Lamp Inputs Optical 2Arc Lamp alignment fixture 3Arc Lamp Assembly access door Arc Lamp Remove and Replace Optical Optical Path Optical Path Main Function Optical Path Operation Optical Path InputsOptical Path Outputs Optical 6Optical Path Optical Path Service Adjustments 7Optical Path 8XY Positioner adjust holes ILA Inputs ILAILA Main functions ILA Outputs ILA Service Adjustments ILA Operation Optical Optical Optical Optical ILA Remove and Replace Relay Lenses Projection Lens Optical Optical Electronics 1Model 250 System Block Diagram System Controller PCB System Controller PCB Main Function Electronics Electronics 5System Controller PCB I/O Diagram for other PCBs System Controller PCB Inputs System Controller PCB Outputs System Controller PCB Operation Electronics System Controller PCB Remove and Replace Video Processor PCB Inputs Video Processor PCBVideo Processor PCB Main Functions 7Video Processor PCB I/O diagram for VICs and Power Supplies 8Video Processor PCB I/O diagram for PCBs Video Processor PCB Outputs Video Processor PCB Operation 9Video Processor PCB LEDs Video Processor PCB Remove and Replace Raster Timing Generator PCB Raster Timing Generator PCB Main Functions 11Raster Timing Generator for other PCBs Raster Timing Generator PCB Inputs Raster Timing Generator PCB Outputs Raster Timing Generator PCB Operation 12LEDs on the Raster Timing Generator PCB Raster Timing Generator PCB Remove and Replace Horizontal Vertical Deflection PCB Inputs Horizontal Vertical Deflection PCBHorizontal Vertical Deflection PCB Main Functions 13Horizontal/Vertical I/O Diagram Electronics Horizontal Vertical Deflection PCB Outputs Horizontal Vertical Deflection PCB Operation Horizontal Vertical Deflection PCB Service Adjustments 16Red image needs vertical adjustment decrease Electronics Convergence Deflection PCB Main Functions Convergence Deflection PCBHorizontal Vertical Deflection PCB Remove and Replace Convergence Deflection PCB Inputs Convergence Deflection PCB Outputs 19Convergence Deflection PCB I/O Diagram 20Convergence Deflection PCB I/O Diagram 21Physical layout of the Convergence/Deflection PCB Convergence Deflection PCB Operation Convergence Deflection PCB Remove and Replace Scan Reversal PCB Inputs Scan Reversal PCBScan Reversal PCB Main Functions Scan Reversal PCB Outputs 22Scan Reversal PCB I/O Diagram Electronics 24Scan Reversal PCB I/O Diagram for CRT Yokes Scan Reversal PCB Operation Electronics Scan Reversal PCB Service Adjustments Electronics 1Projection orientation jumper settings Video Amplifier PCB Main Functions Video Amplifier PCBScan Reversal PCB Remove and Replace Video Amplifier PCB Inputs 26Video Amplifier PCB I/O Diagram Video Amplifier PCB Outputs Video Amplifier PCB Operation Video Amplifier PCB Remove and Replace Electronics 28Video Amplifier PCB showing CRT Socket Connectors CRT/Yoke Assemblies Inputs 10 CRT/Yoke AssembliesCRT/Yoke Assemblies Main Function CRT/Yoke Assemblies Output CRT/Yoke Assemblies Service Adjustments CRT/Yoke Assemblies Operation Electronics Electronics Electronics 30View of CRTs, Relay lenses and ILA Assemblies CRT/Yoke Assemblies Remove and Replace Video Input Cards VICs Standard Rgbhv VIC Rgbhv VIC Main Functions Rgbhv VIC Outputs Rgbhv VIC Service AdjustmentsRgbhv VIC Inputs Rgbhv VIC Operation Graphics Enhancer Plus Rgbhv VIC Grahics Enhancer Plus Rgbhv VIC Main Functions Graphics Enhancer Plus VIC Inputs Graphics Enhancer Plus VIC Outputs Graphics Enhancer Plus VIC Remove and Replace Graphics Enhancer Plus VIC Service AdjustmentsGraphics Enhancer Plus VIC Operation Input Quad Rgbhv VIC Inputs Input Quad Rgbhv VICInput Quad Rgbhv VIC Main Functions 364-Input Quad Rgbhv VIC Input Quad Rgbhv VIC Operation Input Quad Rgbhv VIC Service AdjustmentsInput Quad Rgbhv VIC Outputs Input Quad Rgbhv VIC Remove and Replace YPbPr VIC YPbPr VIC Main Functions YPbPr VIC Operation YPbPr VIC InputsYPbPr VIC Outputs YPbPr VIC Service Adjustments YPbPr VIC Remove and Replace Quad Standard Decoder VIC Quad Standard Decoder VIC Main Functions Quad Standard Decoder VIC Operation Quad Standard Decoder VIC InputsQuad Standard Decoder VIC Outputs Quad Standard Decoder VIC Remove and Replace Quad Standard Decoder VIC Service AdjustmentsQuad Standard Decoder/Line Doubler VIC Electronics 42Backplane Diagram left side Backplane PCB See Figure 44Backplane Diagram right side Electronics Miscellaneous Items Projector Covers Electronics Module Tilt-up Ventilation 1Electronics Module hinge and locking mechanism EMI Filter Air FiltersIR Detectors Cleaning Lenses, ILA Assemblies and Mirrors Miscellaneous Items Troubleshooting LEDs Backpanel LEDs Troubleshooting Troubleshooting Video Processor PCB LEDs Video Processor Test Points Video Processor LEDs Raster Timing Generator PCB LEDs 6Raster Timing Generator LEDs Raster Timing Generator PCB LEDs Convergence Deflection PCB LED Video Amplifier PCB LED Backplane PCB LEDs Diagrams Command on Timing Troubleshooting Image Path Deflection Path Troubleshooting Troubleshooting 14CRT Deflection path between the Scan Reversal PCB and CRT CRT Protection Troubleshooting 16CRT Protection path between the Scan Reversal PCB and CRT Error Codes IIC Handler Troubleshooting Troubleshooting Troubleshooting Guide Problem Check Possible Solution Section Troubleshooting on the Backplane PCB 17Backplane Diagram left side Lamplit Lampok Lampena Coveron GND 19Backplane Diagram right side Troubleshooting Software and Protocol Software Updating Command Software and Protocol Updating Configuration Importing/Exporting Exporting Windows Terminal Transfers + Receive Text File Similar message is displayed on the projector screen Importing Stop, Pause, % complete bar, Sending EXPORT1.TXT Data Transfer Error Example Model 250 Menu will display Null Modem Adapter Terminal Preferences Terminals and Communication ProtocolsTerminals Communications Protocol POS RGB Software and Protocol Software and Protocol Replacement Parts List Description Description Spares Description Quantity Parts List Arc Lamp Cross-member AssemblyAmorphous Aspect Ratio Frame Laser Power SupplyField Horizontal Scan Luminance ResolutionLumen Noise Saturated Color Vertical ResolutionVideo Scan Vertical Synchronization Vertical Scan FrequencyVertical Scan Frequency