Hughes JVC Projector 230 Service Manual
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Chapter 2---System Description Model 230 Service Manual2-29 HIGH VOLTAGE POWER SUPPLY INPUTS DESCRIPTION G1_SUPPLY Supply for G1 grid of CRTs. About -200 V G2_SUPPLY Supply for G2 (screen) grid of CRTs. About 1200 V RED_FOCU S GRN_FOCU S BLU_FOCU SFocus supply for CRTs. about 7 KV OUTPUTS DESCRIPTION ARC_GND CRT ground (anode supply return line) HORIZONTAL/VERTICAL DEFLECTION BOARD INPUTS DESCRIPTION /SWEEP_OK Deflection detection line. open collector, low = good deflection RASTER TIMING GENERATOR BOARD INPUTS DESCRIPTION BLANKING Blanking signal. logic F type CRTS OUTPUTS DESCRIPTION RED_FOCU S GRN_FOCU S BLU_FOCU SFocus supply of CRTs. about 7 KV. RED_GRID1 GRN_GRID1 BLU_GRID1Grid 1 (G1) signal of CRTs. RED_HEAT+ GRN_HEAT +BLU_HEAT +Positive side of the heater voltage for CRTs. About 6.2 V.
Chapter 2---System Description 2-30Model 230 Service Manual RED_HEAT- GRN_HEAT- BLU_HEAT-Negative side (return line) of the heater voltage for CRTs. Ground level. RED_ CATHODE GRN_ CATHODE BLU_ CATHODEVideo output signals of the VAB. about 40 VPP with peak voltage of about 70 V. RED_GRID2 GRN_GRID2 BLU_GRID2G2 (screen) supply of CRTs. about 600 to 800 V OUTPUTS DESCRIPTION ARC_GRD Ground of CRTs ( anode supply return line). SYSTEM POWER SUPPLY INPUTS DESCRIPTION +6.2 V +6.2 V supply line (heater voltage). +15 V +15 V supply for use by Video Amplifier Board. -15 V -15 V supply for use by Video Amplifier Board. +80 V +80 V supply for use by Video Amplifier Board. Interlocks and protection: None 2.3.6 System Controller PCB The System Controller Board (SCB) is located in the electronic card cage (Figure 5-1). The Electronics System is controlled by the SCB. The SCB uses digital and analog circuits to direct the operation of image and raster generation circuits and to control the input/output of power supply operation. The SCB sets the operating parameters of the image, such as brightness and contrast. It also produces internal test patterns and generates on-screen display overlays. The SCB sets the timing for the raster generation to adjust phase, geometric corrections, shading corrections, and convergence. The program memory and the memory for all convergence and shading maps are located on the SCB. The following functions are performed or controlled by the System Controller: • Enables control for the Low Voltage Power Supply, Arc Lamp and cooling fans.
Chapter 2---System Description Model 230 Service Manual2-31 • Fault monitors the HVPS, LVPS, Arc Lamp, and fans. • Provides interboard communication via the IIC serial bus. • Controls Zoom and Focus of the Projection Lens. • IIC Interface control • Provides Video Overlays • X and Y convergence control • Threshold and Sensitivity for shading • I/O control • Two RS-232 serial interface ports • Infrared (IR) remote control interface. Accepts input from front or rear IR detectors. • A 5-wire JTAG interface port for CPU emulation support. • External 3 color system status LEDs. Green indicates normal, yellow is standby and red indicates a fault condition. • External Service Mode switch (see Figure 5-1). Pressing this switch during a power-up sequence brings the system up in a diagnostic mode (for maintenance) rather than a normal operating mode. The SCB I/O diagram (Figure 2-12) and the list of Inputs and Outputs (Table 2- 11) provide information for the technician to perform module-level troubleshooting.
Chapter 2---System Description 2-32Model 230 Service Manual P11 B23 B24 B28 B29 B32 B27 B26 B31 B30 Lens Zoom Lens Focus /LV_ENA /FAN_ENA /LAMP_ENA/HV_OK/LV_OK /LAMP_LIT/LAMP_OK P10 B31 B30 A32 A31 A30 A B 20-20 21-21 22-22 23-23 24-24 25-25 26-26 27-27 28-28 29-29+5.1V stby +5.1V +15V -15V GND ODD_FIELD SRC_VALID H_DRIVE_SC V_DRIVE B9 B10 B2 B1 B3 RED_OVER GRN_OVER BLU_OVERB18 B17 B16 P10 Y_RED_CONV Y_GRN_CONV Y_BLU_CONV X_RED_CONV X_GRN_CONV X_BLU_CONV B4 B5 B6 B1 B2 B3 BLU_THRES GRN_THRES RED_THRES BLU_SENS GRN_SENS RED_SENS B8 B9 B10 B11 B12 B13IIC_DATA IIC_CLK1 IIC_CLK IIC_CLK3IIC_CLK2 SYSTEM CONTROLLER BOARD TO PROJ LENS FROM LVPS FROM HVPS FROM ALPS FROM RTG FROM LVPSTO VPB TO CDB TO VPB H_F2V Figure 2-12. System Controller Board, Block Diagram. IIC Interface Communications are performed through the IIC bus to the other PCBs in the system.This three wire bus interface consists of clock line, data line and interrupt line. Data transferred over the IIC bus is listed in Table 2-9 (I/O signals). System Controller Board Input/Output This section provides a description of the inputs to and outputs from the SCB. The I/O descriptions are arranged by the source/destination of the signal. The format used is such that the assembly communicated with is used as the primary heading of each output. Input refers to an input to the SCB, output refers to an output from the SCB.
Chapter 2---System Description Model 230 Service Manual2-33 Table 2-11. System Controller Board I/O signals VIDEO PROCESSOR BOARD I/O DESCRIPTION IIC_CLK IIC clock line. Clock line for control of synchronous data transfer over the IIC bus interface. IIC_DATA IIC data line. Serial line for synchronous data transfer of the following data between Video Processor Board and SCB board. I=Input, O=Output. I BEAM CURRENT I OK DETECT O RED_CONT O GRN_CONT O BLU_CONT O BRIGHTNESS O RED_G2 O BLU_G2 O GRN_G2 O WHT_BOOST O BLK_BOOST OUTPUTS DESCRIPTION OVERLAY Overlay control signal /IIC_INT IIC interrupt line. RED_OVER Red signal of on-screen menu and/or internal test pattern GRN_OVER Similar to RED_OVER BLU_OVER Similar to RED_OVER BLU_THRES Threshold correction information for blue. Real time data at 0 volt to 1 volt. GRN_THRESSimilar to BLU_THRES RED_THRESSimilar to BLU_THRES
Chapter 2---System Description 2-34Model 230 Service Manual BLU_SENS Sensitivity correction information for BLU. Real time data at O volt to 1 volt. GRN_SENS Similar to BLU_SENS RED_SENS Similar to BLU_SENS RASTER TIMING GENERATOR INPUTS DESCRIPTION SOURCE_ VALIDThis signal indicates a new source (or valid). A high indicates a valid stable signal and low indicates change in input signal. ODD_FIELD Square wave with 50 % duty cycle which is low during the odd field of an interlace signal. This signal is high for noninterlaced signals. 280_CLK Square wave signal, 50 % duty cycle, 280 times the frequency of horizontal sync. This clock is synchronized to the horizontal sync. H_DRIVE Square wave 50% duty cycle synchronized to selected horiz sync V_DRIVE Square wave negative going pulse synchronized to selected vertical sync with pulse width of about 4 horiz lines H_F2V DC voltage proportional to horiz frequency OUTPUTS DESCRIPTION ISYNC_CLK 5 mHz clock used to generate the internal sync signals IIC_CLK IIC clock line. Unidirectional clock line for control of synchronous data transfer over the IIC bus interface. IIC_DATA IIC data line. Bidirectional serial line for synchronous data transfer between System Controller and RTG. CONVERGENCE/DEFLECTION BOARD OUTPUTS DESCRIPTION IIC_CLK IIC clock line. Unidirectional clock line for control of synchronous data transfer over the IIC bus interface. IIC_DATA IIC data line. Bidirectional serial line for synchronous data transfer between the SCB and the Convergence/Deflection board. X_RED_ CONVRed X convergence waveform. The amplitude for full scale correction is about 1 VPP. X_GRN_ CONVGrn X convergence waveform. The amplitude for full scale correction is about 1 VPP.
Chapter 2---System Description Model 230 Service Manual2-35 X_BLU_ CONVBlu X convergence waveform. The amplitude for full scale correction is about 1 VPP. Y_RED_ CONVRed Y convergence waveform. The amplitude for full scale correction is about 1 VPP. Y_GRN_ CONVGrn Y convergence waveform. The amplitude for full scale correction is about 1 VPP. Y_BLU_ CONVBlu Y convergence waveform. The amplitude for full scale correction is about 1 VPP. CORR_ SYNCSquare wave HCT level synchronous signal for horiz axis. HORIZONTAL/VERTICAL DEFLECTION BOARD OUTPUTS DESCRIPTION IIC_CLK IIC clock line. Unidirectional clock line for control of synchronous data transfer over the IIC bus interface.
Chapter 2---System Description 2-36Model 230 Service Manual IIC_DATA IIC data line. Bidirectional serial line for synchronous data transfer between the SCB and the Horizontal/Vertical Deflection board. I=Input, O=Output. O V_RED_LIN_CONTROL O V_GRN_LIN_CONTROL O V_BLU_LIN_CONTROL O V_RED_EDGE_CONTROL O V_GRN_EDGE_CONTROL O V_BLU_EDGE_CONTROL O L/R_KEY_CONTROL O L/R_PIN_CONTROL O WIDTH_CONTROL O H_RED_CENT_CONTROL O H_GRN_CENT_CONTROL O H_BLU_CENT_CONTROL O V_RED_CENT_CONTROL O V_GRN_CENT_CONTROL O V_BLU_CENT_CONTROL O FRONT/REAR O FLOOR/CEIL HIGH VOLTAGE POWER SUPPLY INPUT DESCRIPTION /HV_OK The high voltage status line. Low = operational HVPS. LOW VOLTAGE POWER SUPPLY INPUTS DESCRIPTION + 5.1V Power for digital portion of SCB +15V Power for the analog portions of the SCB -15V Power for the analog portions of the SCB +5.1V_Stby Standby power to the CPU and peripherals. /LV_OK Tells SCB status of non-standby supply (all outputs working or not)
Chapter 2---System Description Model 230 Service Manual2-37 OUTPUTS DESCRIPTION FAN_ENA Signal to enable the 24V standby power LV_ENA Signal to enable the LVPS ARC LAMP POWER SUPPLY INPUTS DESCRIPTION /LAMP_OK Informs SCB that the Arc Lamp is installed, temperature is within limits, and lamp cooling blower is working /LAMP_LIT Informs the SCB that the Arc Lamp is lit or not lit OUTPUTS DESCRIPTION /LAMP_ENA Enables ALPS power PROJECTION LENS OUTPUTS DESCRIPTION LENS_FOCUSSignal to lens focus motor LENS_ZOOM Signal to lens zoom motor FRONT IR INPUTS DESCRIPTION /FRONT_IR Input from front infrared receiver /REAR_IR Input from rear infrared receiver 2.3.7 Raster Timing Generator PCB The Raster Timing Generator (RTG) is located in the electronic card cage (Figure 5-1). The RTG I/O diagram (Figure 2-13) and the list of inputs and outputs (Tables 2-10 and 2-11) provide information to allow the technician to perform module level troubleshooting. The following functions are provided by RTG board: • Internal sync generation • Sync detection and selection • Serration and equalization pulse removal • Phase locked loop • Blanking pulse generation
Chapter 2---System Description 2-38Model 230 Service Manual • Horizontal and vertical phase adjustments • Interlace detection and odd field pulse generation • Horizontal frequency band selection • Horizontal line count and vertical count generation • IIC interface • Video clamp pulse generation • Source change detection • HVPS sync generation • Horizontal deflection enable circuitry The RTG I/O Diagram (Figure 2-13) and the list of inputs and outputs (Tables 2- 12 and 2-13) provide information for the technician to perform module level troubleshooting. Horizontal frequency band selection and LED logic. The RTG produces a voltage that is proportional to the horizontal frequency which is used by the Horiz/Vert Deflection board, System Controller Board, and the phase locked loop (PLL) section of the RTG board. This DC voltage is used to create the following frequency bands: Band A: from 15 KHZ to 24.5 kHZ. Band B: from 24 KHZ to 29.5 kHZ Band C: from 29 KHZ to 56 kHZ Band D: from 55.5 KHZ to 90 kHZ. These bands are outputted through the IIC interface to be used by the System Controller Board. These lines are also outputs of the RTG board through the Backplane Board. The Horizontal/Vertical Deflection Board uses these lines for proper selection of retrace times.