Hughes Jvc 220 Projector Service Manual

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...

  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....

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...

  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 
•...

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...

  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...

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...

  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...

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...

  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...