Hughes Jvc 200 Projector Service Manual

Chapter 2---System Description 
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...

  Chapter 2---System Description 
OUTPUT DESCRIPTION 
RED_VIDEO Red video output. 0 Volt to 1 Volt. 
GRN_VIDEO Similar to RED_VIDEO 
BLU_VIDEO Similar to RED_VIDEO 
RESTORE DC RESTORE control signal. When this signal is asserted, the 
 DC level of the video signal is clamped at the proper value 
 on the VAB. 
RED_G2 Red CRT G2 voltage adjust control signal. 
GRN_G2 Similar to RED_G2 
 BLU_G2  Similar to RED_G2 
 G1_BIAS   Control the adjustment of G1 voltage for all three CRTs 
   External Video
 INPUT...

Chapter 2---System Description 
 
 /SEL_VIC #1  Input signal from RGB VIC board which is used to select 
  input video source from VIC #1. 
 /SEL_VIC #2  Similar to /SEL_VIC #1 
 /SEL_VIC #3  Similar to /SEL_VIC #1  
 Low Voltage Power Supply 
INPUTS  DESCRIPTION 
+ 5.1 volts  Power supply to digital components 
+ 15 Volts  Power supply to analog components 
- 15 Volts  Power supply to analog components 
 
Model 200 Service Manual  2-29  

  Chapter 2---System Description 
2.3.5   Video Amplifier 
The Video Amplifier Board (VAB) is located at the back side of the 
projector under the necks of the three CRTs. It contains three 
separate video amplifiers, one each for red, green, and blue. The 
outputs from these video amplifiers connect directly to the CRTs 
and provide all electrical connections to the CRTS except for the 
anode voltages.  
The following functions are provided by VAB: 
• Amplification of video signals and driving the...

Chapter 2---System Description 
RED_VIDEOGRN_VIDEOBLU_VIDEO
BLANKINGG1 SUPPLYG1 BIAS
RESTORE
ARC_GND
BLU_CATHODE8BLU_GRID19BLU_GRID210
BLU_BEAM16
BLU_HEAT-7BLU_HEAT+6
ARC_GND3
GRN _CATHODE8GRN _GRID19GRN _GRID210
GRN_BEAM14
GRN _HEAT-7GRN _HEAT+6
ARC_GND3
RED _CATHODE 8RED _GRID1  9RED _GRID2 10
RED_BEAM        12
RED _HEAT-      7RED _HEAT+  6
ARC _GND   3
246
23
2112
13      GRN_G215      BLU_G2
1     G2 SUPPLY
11      RED_G2
19   /SWEEP_OK
3     + 8OV7     + 15V5     + 6.2V9     -15V
/VA_OK...

  Chapter 2---System Description 
Table 2-8.  Video Amplifier I/O signals 
Video Processor Board 
INPUTS DESCRIPTION 
RED_VIDEO 
GRN_VIDEO 
BLU_VIDEO 
Video preamp signals. About 0.5 VPP 
G1_BIAS Brightness control line. 0 to 5 V DC 
RED_G2 
GRN_G2 
BLU_G2 
Black level (G2) control lines 0 to 3.1 V 
RESTORE Video DC restoration pulse. logic HC positive going  4% duty cycle 
OUTPUTS DESCRIPTION 
/VA_OK VAB status line. Low = good VAB. High = Bad VAB (This signal is 
called /HV_ENABLE at the HVPS)....

Chapter 2---System Description 
Raster Timing Generator Board  
INPUTS DESCRIPTION 
BLANKING Blanking signal. logic F type 
CRTs 
OUTPUTS DESCRIPTION 
RED_FOCUS 
GRN_FOCUS 
BLU_FOCUS 
Focus supply of CRTs. about 7 KV. 
RED_GRID1G
RN_GRID1BL
U_GRID1 
Grid 1 (G1) signal of CRTs. 
RED_HEAT+
GRN_HEAT+
BLU_HEAT+ 
Positive side of the heater voltage for CRTs. About 6.2 V. 
RED_HEAT-
GRN_HEAT-
BLU_HEAT- 
Negative side (return line) of the heater voltage for CRTs. Ground 
level. 
RED_ 
CATHODE 
GRN_ 
CATHODE...

  Chapter 2---System Description 
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...

Chapter 2---System Description 
P11
B23B24
B28B29
B32
B27
B26
B31B30
Lens ZoomLens Focus
/LV_ENA/FAN_ENA
/LAMP_ENA
/HV_OK
/LV_OK
/LAMP_LIT/LAMP_OK
P10B31B30A32A31A30
A   B20-2021-2122-2223-2324-2425-2526-2627-2728-2829-29
+5.1V stby
+5.1V
+15V-15VGND
ODD_FIELD
SRC_VALIDH_DRIVE_SCV_DRIVE
B9B10B2B1B3
RED_OVER
GRN_OVER
BLU_OVER
B18B17
B16
P10
Y_RED_CONVY_GRN_CONVY_BLU_CONVX_RED_CONVX_GRN_CONVX_BLU_CONV
B4B5B6B1B2B3
BLU_THRESGRN_THRESRED_THRESBLU_SENSGRN_SENSRED_SENS
B8B9B10B11B12B13
IIC_DATA...

  Chapter 2---System Description 
IIC_DATA IIC data line. Serial line for synchronous data transfer of the followin\
g 
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...