Hughes Jvc 220 Projector Service Manual

Chapter 3 Service Adjustments 
3.4 ILA® Back Focus 
The ILA® Back Focus adjustment moves the ILA®/Relay Lens/CRT 
assemblies together to adjust the focal length. This adjustment 
allows the zoom lens’ tracking to remain focused throughout the 
entire range. Use focus test pattern to perform this adjustment one 
color at a time. This procedure performs the Green ILA® Back 
Focus. 
For best results, perform ILA® Back Focus with 2 people.  One 
person will watch the screen close-up and the other will move...

Chapter 3---Service Adjustments 
12. Repeat Steps 6-11 until the spacer balls stay in focus through 
the entire zoom range. The spacer balls may go slightly out of 
focus in spots while zooming up or down, but they should be in 
focus at the smallest and largest images. 
13. Tighten the hex bolts on the Green ILA® Assembly and the 
wing nut on the Green Relay Lens. 
14. Repeat Steps 6-11 above for any other assembly needing ILA® 
Back Focusing. Be sure to hide the other 2 colors. 
 
NOTE: The CRT...

Chapter 3 Service Adjustments 
(be careful not to loosen the CRT thumbscrew which could 
cause the CRT to rotate). 
8. Tighten the set screws first, then the CRT focus lock screw. 
NOTE: Tighten set screws before focus lock screw. The focus 
lock screw can slightly defocus or rotate the CRT as it is being 
tightened if the set screws are loose. 
9. Repeat the above steps for the Red and Blue CRTs. 
 
Figure 3-5.   CRT Mechanical Focus adjustments. 
3.6 CRT Rotation 
The CRT tilt adjustment aligns the CRT...

Chapter 3---Service Adjustments 
1. Select Test Pattern 8, Center/Lin. 
2. View the color for the CRT that requires rotation. Hide the other 
2 colors. 
3. In the Geometry menu, set “Reg Enable” to off by unchecking 
the box. Unchecking the Reg Enable box temporarily disables 
any convergence corrections that have been performed with a 
different CRT/Yoke assembly and sets these values to the 
default levels so that CRT Rotation can be accomplished 
correctly. 
4. In the Geometry menu, access Bow, Skew,...

Chapter 3 Service Adjustments 
4. Adjust the Green Electronic Focus (Figure 3-6) for a sharp 
focus of the H pattern at the center of the screen. 
5. Repeat the above steps for Red and Blue. 
 
Figure 3-6.   RGB Electronic Focus adjustments. 
3.8 ILA® Overlap 
This adjustment positions the ILA® assemblies in their sockets. 
Adjustment should only be made once or whenever an ILA® is 
replaced. 
To determine if this adjustment is necessary: 
1. Note the value of the ILA® bias for Red, Green and Blue so...

Chapter 3---Service Adjustments 
2. Loosen the 2 wing nuts at the top of the ILA® assembly to be 
adjusted (Figure 4-12). 
3. If the overlap is at the left or right, grasp the ILA® assembly and 
slide it to the right or left so that the edges coincide with the 
edges of the other two ILA® assemblies. CAUTION! To avoid 
damaging the connector, grasp the ILA® assembly itself, not 
the connector at the top. 
4. If the overlap is at the top or bottom, be sure the projector is 
level, then slide the spring...

Chapter 3 Service Adjustments 
 
Figure 3-7.   Scan Reversal Board. 
To set the Horizontal Scan Jumper: 
1. Turn power off at the projector and wait for the arc lamp to cool. 
2. Remove the projector rear cover (Section 4.2). 
3. Verify that the jumper is plugged into JA50 and J101 for rear 
projection or J50 and J100 for front projection (See Figure 3-7). 
Change jumper if necessary. 
4. Replace the projector cover. 
5. When changing jumpers for front or rear screen projection, 
Centering, convergence...

Chapter 3---Service Adjustments 
4. Verify that the vertical jumper is inserted in the correct jacks for 
appropriate application, (see Figure 3-7).  Change jumpers if 
necessary. 
5. Replace the electronic module and rear cover. 
6. When changing jumpers for floor or ceiling screen projection, 
Centering, convergence and shading will need to be rechecked. 
3.10 Vertical and Horizontal Size Settings 
Adjust the vertical height pots and horizontal size coils when 
replacing the Horizontal/Vertical...

Chapter 3 Service Adjustments 
top and higher at the bottom, adjust Red vertical pot to correct 
the error. 
 If Red is higher than Green at the top and bottom, or lower than 
Green at the top and bottom, this is most likely caused by Red 
not being centered correctly and can be corrected with the 
centering adjustment (User’s Guide, Section 5.5.11).  
 If the Red height pot does not completely eliminate the 
difference in height between Red and Green, balance the error 
at the top and bottom. Too much...

Chapter 3---Service Adjustments 
To perform software upgrade: 
1. Verify that the projector circuit breaker is off. Use a Null Modem 
cable to connect a PC to the projector’s Serial Port A. 
2. Start Windows 3.1. 
3. Click on the terminal icon from the Accessories Directory. 
4. From the Terminal menu, select Settings-Terminal Emulation 
and click on DEC-VT-100(ANSI).  
Select OK. 
5. Under Settings choose Terminal Preferences. 
6. Under Terminal Preferences the following selections are 
appropriate;...