Hughes Jvc 220 Projector Service Manual
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Chapter 2---System Description operation and pinouts are the same as the Standard RGBHV VIC. One of four LEDs indicates which of the four RGB inputs is currently active. HDTV YPbPr VIC This color decoder video input card (YPbPr_VIC) is located on the back side of the projector and contains three BNC input connectors which can be used for two different inputs, YPbPr or GBR. This board converts these color component signals to RGB type video signals. The following functions are provided by YPbPr_VIC: • Video input and output buffers • Conversion of color components signals to RGB video signals • Separation of syncs from the Y/G input signal • Hue, sharpness, gamma, and color adjustment • Selection of RGB input or color component input • LED indication • IIC serial bus interface RED GRN BLU HOR /SELECT Y/G Pb/B Pr/R IIC_CLK IIC_DATA +5.1V_STBY +5.1V +15V -15V B2 B4 B6 B8 B12 B13 A13 A16 B16 B15 B14 Pin callouts are to P12, P14, or P18, depending on whichVIC slot is being used. Figure 2-8. HDTV YPbPr VIC Input/Output Diagram. This VIC accepts two types of video signals, color components (YPbPr) and RGB signals. In either case the output of this VIC is RGB type signals. If the inputs are color components they will be converted to RGB type signals. Model 220 Service Manual 2-17
Chapter 2---System Description The selection between color component input mode and RGB input mode is controlled by an input. This input is controlled by the System Controller Board via the IIC serial bus interface. LED indication There are two LEDs on this VIC. The RGB LED glows when the YPbPr_VIC is selected and is in RGB input mode. The YPbPr LED glows when the YPbPr_VIC is selected and is in YPbPr input mode. Both LEDs are off when the YPbPr_VIC is not selected as the input to projector. Only one LED can be on at one time. IIC Interface The YPbPr_VIC is controlled by the serial bus interface. The IIC bus comes from the System Controller Board through the Backplane Board. All required adjustments for this board are provided via the IIC serial bus interface. The information transferred over the IIC bus is indicated below (I = input to YPbPr_VIC, and O = output of YPbPr_VIC). The selection of this VIC is accomplished through the IIC control bus which provides the /SEL_VIC signal. Table 2-4. HDTV VIC IIC Interface I/O Bits Information Description I 1 /SEL_YPbPr Selects YPbPr input mode for the YPbPr_VIC. Low = Selected YPbPr input mode. I 1 /SEL_RGB Selects RGB input mode for the YPbPr_VIC. Low = Selected RGB input mode. I 8 GAMMA Data for adjustment of Gamma correction I 8 COLOR Data for adjustment of color I 8 HUE Data for adjustment of hue I 8 SHARPNESS Data for adjustment of sharpness O 4 VIC_ID VIC identification lines. 0001 for YPbPr_VIC O 1 VIC_MODEL Revision of the YPbPr_VIC. O 1 /YPbPr_OK YPbPr_VIC status line. Low = operational YPbPr_VIC The HDTV YPbPr_VIC I/O This section provides a comprehensive description of the inputs to and outputs from the YPbPr_VIC. 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 group of signals. Those signals are 2-18 Model 220 Service Manual
Chapter 2---System Description further subdivided into inputs and outputs. Input refers to an Input to the YPbPr_VIC, output refers to an output from the YPbPr_VIC. Table 2-5. HDTV VIC Signals PROJECTOR INPUTS INPUT DESCRIPTION Y/G Pb/B Pr/R Video input signals-about 0.7 to 1 VPP VIDEO PROCESSOR BOARD OUTPUT DESCRIPTION /SELECT Selection indicator for VIC. Low indicates the selected YPbPr_VIC. RED GRN BLU Video signals. about 0.7 to 1 VPP HOR Composite horizontal / vertical sync signal SYSTEM CONTROLLER BOARD INPUTS 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 system control board and the YPbPr_VIC. OUTPUTS DESCRIPTION /IIC_INT IIC interrupt line. YPbPr_VIC does not initiate any interrupt LOW VOLTAGE POWER SUPPLY INPUTS DESCRIPTION +5.1 V +5.1 V supply for use by YPbPr_VIC. +15 V + 15 V supply for use by YPbPr_VIC. -15 V -15 V supply for use by YPbPr_VIC. Interlocks and protection Inputs: None Model 220 Service Manual 2-19
Chapter 2---System Description Outputs: None Quad Standard Decoder VIC The Quad Standard Decoder VIC is composite and S-Video interface. It contains three BNC input connectors for Composite Video and S-Video (luminance and chrominance). This decoder VIC converts these color component signals to RGBHV type video signals. The following functions are provided by the Quad Standard Decoder VIC: • Select input source-Composite or S-video • Select standard-AUTO/NTSC/PAL/SECAM/4.43NTSC • Conversion of composite and S-video signals to RGB video signals • Separation of syncs from the input signal • Tint, sharpness, and color adjustment • LED indication of Composite or S-video • IIC serial bus interface R G B /H /SELECT Comp Y in C in IIC_CLK IIC_DATA +5.1V +15V B2 B4 B6 B8 B12 B13 A13 B16 B15 Pin callouts are to P12, P14, or P18, depending on whichVIC slot is being used. /VB10 Figure 2-9. Quad Standard Decoder I/O Diagram. LED Indication There are two LEDs on this VIC. The LED on the right side of the board glows when Composite Video is selected and the LED on 2-20 Model 220 Service Manual
Chapter 2---System Description the left glows when S-Video is selected. Only one LED can light at one time. IIC Interface The Quad Standard Decoder VIC is controlled by the serial bus interface. The IIC bus comes from the System Controller Board through the Backplane Board. All required adjustments for this board are provided via the IIC serial bus interface. The information transferred over the IIC bus is indicated below (I = input to YPbPr_VIC, and O = output of YPbPr_VIC). The selection of this VIC is accomplished through the IIC control bus which provides the /SEL_VIC signal. Table 2-6. Quad Standard Decoder VIC IIC Interface I/O Information Description I SOURCE Selects input source (Composite Video or S- Video) I STANDARD Selects signal standard (AUTO/NTSC/PAL/SECAM/4.43NTSC) Model 220 Service Manual 2-21
Chapter 2---System Description I TINT Data for adjustment of Hue I COLOR Data for adjustment of color I SHARP Data for adjustment of Sharpness I VTR Selection of VTR mode O VNR Selection of Video Noise Reduction mode Quad Standard Decoder VIC I/O This section provides a description of the inputs to and outputs from the Quad Standard Decoder VIC. 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 group of signals. Those signals are further subdivided into inputs and outputs. Input refers to an Input to the VIC, output refers to an output from the VIC. Table 2-7. Quad Standard Decoder VIC Signals PROJECTOR INPUTS INPUT DESCRIPTION Composite V Video input signals-about 0.7 to 1 VPP S-Video Video input signal-about 0.7 to 1 VPP for Luminance and about .3-.6 VPP for Chrominance (Burst) VIDEO PROCESSOR BOARD OUTPUT DESCRIPTION /SELECT Selection indicator for VIC. Low indicates the Quad VIC is selected. RED GRN BLU Video signals. about 0.7 to 1 VPP H, V Horizontal/vertical sync signals, about 1-1.25 VPP SYSTEM CONTROLLER BOARD INPUTS 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 System Control Board and the VIC. 2-22 Model 220 Service Manual
Chapter 2---System Description LOW VOLTAGE POWER SUPPLY INPUTS DESCRIPTION +5.1 V +5.1 V supply for use by The Quad Decoder VIC. +15 V + 15 V supply for use by the Quad Decoder VIC. Interlocks and protection None 2.3.4 Video Processor PCB The Video Processor Board (VPB) is the bottom-most card (see Figure 5-1) in the card cage. It is connected directly to the Backplane board through 2 connectors. When an external signal is being received, the VPB provides Horizontal Sync, Vertical Sync, and Green Sync signals to the Raster Timing Generator (RTG) board. It also provides three primary color signals, and G2, G1 bias and DC RESTORE control signals to the Video Amplifier Board (VAB). The following functions are provided by the VPB: • Video signal input and multiplexing • Sync signal stripping • Overlay signal multiplexing • Brightness and Contrast control, and DC RESTORE • Video signal gamma correction • Sensitivity and Threshold signal input and control • Automatic limiting for Contrast, G2, and internal video The Video Processor I/O diagram and the list of inputs and outputs provide information to allow the technician to perform module-level troubleshooting. Model 220 Service Manual 2-23
Chapter 2---System Description B31 RED_VIC#1B29 RED_VIC#2B27 RED_VIC#3 B23 GRN_VIC#2B21 GRN_VIC#3B19 BLU_VIC#1 B25 GRN_VIC#1 B24 RED_THRESHB23 GRN_THRESHB22 BLU_THRESH B25 BLU_SENS B17 BLU_VIC#2B15 BLU_VIC#3B13 H_VIC#1 B9 H_VIC#3B7 V_VIC#1B5 V_VIC#2 B11 H_VIC#2 B3 V_VIC#3 GRN_G2 A20BLU_G2 A21 G1_BIAS A11 RED_G2 A19 B20 GRN_BEAMB21 BLU_BEAMA13 /VA_OK (/HV_ENA) B19 RED_BEAM A8 +5.1VA9 +15V A10 -15V B12 IIC_CLKB13 IIC_DATAA12 /IIC_SINT B27 RED_SENSB26 GRN_SENS B29 OVERLAY B15 CLAMPB15 BLANKING RESTORE B16 A2 /SEL_VIC#1B1 /SEL_VIC#2 GRN_VIDEO B4RED_VIDEO B2 BLU_VIDEO B6 V_SYNC A16H_SYNC A17 GRN_SYNC B17GRN INPUT A28 A1 /SEL_VIC#3 B32 RED_OVERB31 GRN_OVERB30 BLU_OVER J17 J16 J16 EXTERNALVIDEO FROMSCB FROM RTG FROMSCB FROM/TO VAB FROMLVPS TORTG TOVAB TOVAB TOVAB VIDEO PROCESSOR BOARD Figure 2-10. Video Processor I/O Diagram IIC Interface The VPB communicates with the SCB via the IIC bus. The information transferred over the bus (as shown in Table 2-8) is indicated as follows (I = Input to the VPB, O = Output from the VPB): Table 2-8. Video Processor IIC communication I/O Information Description I RED_CONT Red Contrast level I GRN_CONT Green Contrast level I BLU_CONT Blue Contrast level 2-24 Model 220 Service Manual
Chapter 2---System Description I BRIGHTNESS Brightness level I BEAM CURRENT Beam Current I RED_G2 Red G2 Control I GRN_G2 Green G2 Control I BLU_G2 Blue G2 Control I WHT_BOOST Gamma correction I BLK_BOOST Gamma correction I G1_BIAS G1 bias level O /VA_OK Issues to SCB that Video Amplifier is OK O BEAM_CURRENT Beam current control O OK_DETECT Issues to SCB that VPB is OK Video Processor I/O This section provides a comprehensive description of the inputs to and outputs from the VPB. The I/O descriptions in Table 2-9 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 group of signals. Those signals are further subdivided into inputs and outputs. Inputs refers to an input to the VPB, while output refers to an output from the VPB. Table 2-9. Video Processor I/O signals SYSTEM CONTROLLER BOARD INPUT DESCRIPTION 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 OVERLAY Overlay control signal RED_SENS Sensitivity correction information for red. Real time data at 0 volt to 1 volt. GRN_SENS Similar to RED_SENS Model 220 Service Manual 2-25
Chapter 2---System Description BLU_SENS Similar to RED_SENS RED_THRES Threshold correction information for red. Real time data at 0 Volt to 1 Volt GRN_THRES Similar to RED_THRES BLU_THRES Similar to RED_THRES I/O DESCRIPTION IIC_DATA IIC data line. Bidirectional serial line for synchronous data transfer between SCB and other circuit boards. See detailed description for list of signals transferred and data direction IIC_CLK IIC clock line. Unidirectional clock line for control of synchronous data transfer over IIC bus. IIC_INT Interrupt output to SCB RASTER TIMING GENERATOR INPUT DESCRIPTION CLAMP Pulse signal input from the RTG board. Indicates the commanded timing and duration of the DC RESTORE. BLANKING Pulse signal input from the RTG board. Indicates the commanded BLANKING interval during the scan. OUTPUT DESCRIPTION H_SYNC Horizontal sync signal to RTG board V_SYNC Vertical sync signal to RTG board GRN_SYNC Green sync signal to RTG board GRN_INPUT Green video signal to RTG board VIDEO AMPLIFIER INPUT DESCRIPTION RED_BEAM Voltage signal proportional to cathode current averaged over several horizontal lines in the red CRT. Voltage level is + mV/µA 2-26 Model 220 Service Manual