Hughes Jvc 200 Projector Service Manual

Chapter 2---System Description 
2.3   Electronics System 
2.3.1 General Description 
The Model 200 Electronics System includes nine printed circuit 
assemblies. They provide all the controlling voltages and signals 
to adjust and correct picture settings, geometry, convergence, and 
shading (see Chapter 4 of the User’s Guide). The Electronics 
System also controls video and sync input signals, LED displays 
on PCBs at the rear and side of the projector, two RS-232 
communications ports, and two IR...

  Chapter 2---System Description 
2.3.2   Power Supplies 
The Model 200 includes three power supply assemblies. 
• Low Voltage Power Supply 
• Arc Lamp Power Supply 
• High Voltage Power Supply 
Low Voltage Power Supply (LVPS) 
P75
P76
1
3
5
1-7
8
9
10
11
12
13
14
15
16
17
18
To P8 on
BackplaneAC
INPUTLine
Earth
Neutral
LV Ret
/LV_ENA
/LV_OK
+24v Fans
+5.1v STBY
+5.1v
+6.2v
+15V
-15v
+80V
/COVER_ON
/FAN_ENA
 
Figure 2-3.   LVPS Input/Output Diagram 
Main Functions: 
• Provide all the low voltages needed...

Chapter 2---System Description 
+ 24VDC 
+ 80VDC 
/LV_OK: When /LV-ENA is enabled, this diagnostic signal 
indicates to the System Controller the status of the non-standby 
supply (all outputs working or not working). 
Operation: 
The main power is filtered via the input filter to prevent radiation 
from escaping back to the power line. From the line filter, AC 
power is fed into the Low Voltage Power Supply module where AC 
is rectified, filtered, and compensated for power factor correction. 
The +5.1V...

  Chapter 2---System Description 
/COVER_ON: Cover interlock signal. Indicates both covers are in 
place.  
/LAMP_OK: Tells the ALPS that the lamp is installed, the 
temperature is within limits, and the lamp cooling blower is 
working. 
Outputs: 
+140 VDC boost voltage to the Laser Power Supply. 
Voltage: 18 to 25 VDC to maintain the arc lamp ON. 
Current: 30 to 38 amps to maintain the arc lamp ON. 
LAMP_OUT: Lamp output voltage, positive. 
LAMP_RTN: Lamp return. 
/LAMP_LIT: Signal to SCB that the lamp...

Chapter 2---System Description 
• Generation of focus voltage (G3) for all three CRTs (RGB) 
• Generation of screen (G2 supply-Black Level) voltage for all 
three CRTs 
• Generation of G1 supply (Blanking) voltage  
• Dynamic focus amplifier using H and V parabolas 
• External ON/OFF and generation of /HV_OK signal 
The High Voltage Power Supply I/O diagram (Figure 2-5) and the 
list of inputs and outputs (Table 2-1), provide an understanding of 
the operation of the HVPS to allow the technician to...

  Chapter 2---System Description 
HVPS_SYNC Square wave HCT level with 50 or 33% duty cycle synchronized to 
horizontal sync. 
Video Processor PCB
INPUT DESCRIPTION 
/HV_ENA The HVPS enable line. A low enable the HVPS (VA_OK from VPB). 
Video Amplifier PCB
OUTPUTS DESCRIPTION 
G1_SUPPLY DC supply about -150 V for driving the G1 of CRTs 
G2_SUPPLY DC supply about 1.3 KV for driving the G2 of CRTs 
ARC_GND Return (ground) line for the CRT anodes 
Convergence/Deflection PCB
INPUTS DESCRIPTION 
H_ 
PARABOLA...

Chapter 2---System Description 
 
 
CRTs
OUTPUTS DESCRIPTION 
RED_ANODE 
GRN_ANODE 
BLU_ANODE 
Anode supply for the three CRTs. About 25 KV  
RED_FOCUS 
GRN_FOCUS 
BLU_FOCUS 
Focus voltage for the three CRTs. About 7 KV 
 
Interlocks and protection: 
This section describes the interactions between boards where one 
board may cause others to perform protection functions. 
Input  
A high signal at /HV_ENA shuts off the HVPS.  
Model 200 Service Manual  2-13  

  Chapter 2---System Description 
2.3.3   Video Input Cards 
The four types of Video Input Cards that can be used with the 
Model 200 Projector are:  
• Standard RGB Video Input Card, which is supplied with each 
projector and is used for RGB standard formats 
• Optional Four Input RGB VIC used in a similar manner as a 
switcher. 
• Optional HDTV VIC used for High Definition Television. 
• Optional Quad Standard Decoder VIC used for NTSC, PAL 
SECAM and other composite sources. 
Standard RGB Video Input...

Chapter 2---System Description 
LED indication 
The RGB VIC includes an LED which glows when the board is 
selected (i.e. when the /SEL_CH line is low) as the input for the 
Model 200 Projector. 
IIC serial bus interface section 
The RGB_VIC is controlled by the serial bus interface. The IIC bus 
comes from the System Controller Board through the Backplane 
Board. The information transferred over the IIC bus is indicated 
below (I = input to the RGB VIC, and O = output from the RGB 
VIC). The RGB VIC...

  Chapter 2---System Description 
/SEL_VIC Select line for VIC. A low indicates the RGB_VIC is selected. 
RED_VIC 
GRN_VIC 
BLU_VIC 
Video signals. about 0.7 to 1 VPP 
H_VIC Horizontal or composite sync signals 
V_VIC Vertical sync signals 
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...