Hughes Jvc 220 Projector Service Manual

Chapter 2---System Description 
 
X_GRN+ Output of horizontal green convergence amplifier 
X_BLU+ Output of horizontal blue convergence amplifier 
Y_RED+ Output of vertical red convergence amplifier 
Y_GRN+ Output of vertical green convergence amplifier 
Y_BLU+ Output of vertical blue convergence amplifier 
OUTPUTS DESCRIPTION 
X_RED- Current feedback of horizontal red convergence amplifier 
X_GRN- Current feedback of horizontal green convergence amplifier 
X_BLU- Current feedback of horizontal blue...

  Chapter 2---System Description 
 
GRN_LOCK+ Interlock for green yoke. 5 V when closed or 15 V when open. 
GRN_LOCK- Interlock for green yoke . 5 V when closed or 0 V when open.  
V_GRN_YOK+ Top of green vertical yoke 
V_GRN_YOK- Bottom of green vertical yoke 
X_GRN_YOK+ Top of  green horizontal convergence yoke 
X_GRN_YOK- Bottom of green horizontal convergence yoke 
Y_GRN_YOK+ Top of green vertical convergence yoke 
Y_GRN_YOK- Bottom of green vertical convergence yoke- 
BLUE YOKE CONNECTOR
NAME...

Chapter 2---System Description 
2.3.11 Backplane PCB 
The Backplane PCB is the interface that connects the Power 
Supplies, VICs, PCBs, and other components together, either 
through a direct connection to a connector on the Backplane or 
through cables to connectors on the Backplane PCB. Signals are 
not modified in any way by the Backplane. It serves only as an 
interconnecting point. Refer to Figure 2-17 for a general idea of 
how the projector wiring is interconnected through the Backplane 
PCB....

  Chapter 2---System Description 
2.4   Image Light Amplifier Technology 
Section 2.2 explained how the various units, including the ILA® 
assemblies, in the Optical System work together to produce the 
image on the screen. This section focuses mainly on how the ILA® 
assembly itself works. 
An Image Light Amplifier (ILA®) assembly (Figure 2-18) is a 
device that uses low-intensity images to modulate a high-intensity 
light through a liquid crystal layer. It is the key component in 
producing very...

Chapter 2---System Description 
High intensity light from a Xenon Arc Lamp is applied, through a 
prism (where it is polarized), to the output side of the ILA® 
assembly where the liquid crystal layer is located. The polarized 
light passing through the liquid crystal is modulated (changing the  
polarity of the light waves), in accordance with whatever image is 
on the input side of the ILA® assembly.  
The axis of the polarized light is proportional to the brightness on 
the input side of the ILA®...

Chapter 3---Service Adjustments 
3.0  Service Adjustments 
Contents 
3.1   Arc Lamp Focus........................................................................\
...............3-1 
3.2   Arc Lamp Current Setting........................................................................\
3-5 
3.3   Electronic Module Tilt-up........................................................................\
.3-5 
3.4   ILA® Back Focus........................................................................\...

Chapter 3 Service Adjustments 
4.   From the System menu, select Maintenance, then select #3, 
ILA® Bias. Record the ILA® Bias present value (the Green 
bias will be readable). This bias value will be returned to when 
this procedure is complete. Only the Green value needs to be 
recorded. Red and Blue return to their original values when 
Green is reset. 
5. Use the right arrow key to increase the ILA® Bias so the Flat 
Field turns white. If the screen begins to turn from white to a 
yellow-tinge, use...

Chapter 3---Service Adjustments 
 
       Vertical 
Adjustment 
   Horizontal 
Adjustment Slightly 
loosen these 
three screws 
Figure 3-1.  First Condensing Lens (rear of Arc Lamp). 
WARNING!!! The next step reapplies power to the projector. 
Dangerous light exists in the mirror area where the Optical Shield was removed. 
It is crucial that hands and other parts of the body be kept away from t\
he Arc 
Lamp light beam. Severe burns can result from even short exposures to the light 
beam. Do not allow...

Chapter 3 Service Adjustments 
F. Reapply power to the projector. 
G. CAUTION! The First Condensing lens may still be hot! 
Using a small, flathead screwdriver, adjust the horizontal or 
vertical screw (Figure 3-1) on the First Condensing Lens 
Retainer Ring to center the hot spot on the screen. 
H. Retighten the 3 retainer ring screws (Figure 3-1). 
7. Adjust the focus screw for overall brightness from the center to 
the edges with minimum rolloff. NOTE: Rolloff is the gradual 
difference in brightness...

Chapter 3---Service Adjustments 
every 500 hours of operation. This procedure is performed using a 
DVM and a clamp-on type current meter such as AMPROBE 
Model AC/DC 1000 or equivalent.  
To perform the Arc Lamp Current Setting: 
1. Verify that power is off to the projector, or turn power off with 
the remote (it is not necessary for the circuit breaker to be off).  
2. Place a DVM (set to read up to 200VDC) across the Arc Lamp 
± terminals (refer to Figure 4-4 for DVM location).  
3. Turn projector...