Hughes Jvc 220 Projector Service Manual

							Chapter 4---Maintenance (Removal/Replacement) 
4.14   Scan Reversal PCB 
The Scan Reversal PCB is located on the right side of the 
Electronic Module. 
To remove the Scan Reversal PCB: 
1.   Remove the projector rear cover. 
 
Figure 4-10.   Scan Reversal PCB. 
2.   Disconnect 7 connectors; J52, J54, J64, J65, J66, J50 
(or J50A), and J100 (or J101). To remove, push in 
slightly, squeeze the tabs, then pull connector out. 
3.   Move all cables out of the way. 
4.   Remove the 4 pozidrive screws (Figure 4-10) and lift 
the board out. 
5.   Reinstall in the reverse order from above. 
4.15   CRT/Yoke Assembly 
Warning!!! The CRT/Yoke Assemblies should 
be handled with extreme caution. If dropped they can implode and 
flying glass can cause severe injury to personnel. Be careful not to 
bump or drop the CRT. Place in a safe area immediately after 
removal. 
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							 Chapter 4---Maintenance (Removal/Replacement) 
Three CRT/Yoke Assemblies are located in the CRT Assembly 
area below the card cage. To remove a CRT/Yoke Assembly 
(refer to Figure 4-11): 
 
Figure 4-11.   View of CRTs, Relay lenses and ILA® Assemblies. 
1.   Remove front and rear covers (Section 4.2). 
2.   Tilt the Electronic Module up and lock it in place 
(Section 3-3). 
3.   Remove the two pozidrive screws from the top of the 
High Voltage Power Supply (HVPS) cover (Figure 4-5) 
and loosen the one screw at the bottom of the cover 
(do not remove the bottom screw-it is difficult to 
replace-the HVPS will slide up and over it). 
4.   Remove the CRT anode cable (for the CRT that is to 
be replaced) from the HVPS. 
5.   Disconnect the Yoke plug and cable harness from the 
Scan Reversal PCB for the appropriate CRT (see 
Figure 3-7). 
6.   Remove the wires from the cable clamp for the 
CRT/Yoke Assembly that is being removed. 
7.   Loosen the CRT Holder Ring (knurled knob in Figure 
3-5). NOTE: The CRT Holder Ring should be only 
hand-tight. If it cannot be removed by hand only, a 
flathead screwdriver can be used in the slots on the 
CRT Holder Ring to help loosen it. Do not use a tool of 
any kind to tighten this ring-it should be hand tight only. 
8.   CAUTION! For the Green CRT/Yoke Assembly 
only, this step is best performed with the Green CRT 
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							Chapter 4---Maintenance (Removal/Replacement) 
still connected to the CRT socket connector and the 
ground wire still connected from the CRT to the socket 
connector. This is because the Green socket connector 
is close to the rear of the projector and is easier to 
disconnect from the CRT after the CRT/Yoke Assembly 
is loose and is moved away from the rear. Be careful 
not to break any of these connections.  
Gently remove the CRT/Yoke Assembly by sliding it 
backward and upward as far as possible before 
unplugging the CRT socket connector from the neck. 
Use caution to avoid bumping the CRT/Yoke Assembly 
as it is being removed. 
9.   After removing the CRT/Yoke Assembly, carefully 
unplug the CRT socket connector and the ground wire 
that connects the CRT to the socket connector. NOTE: 
It may be helpful to have another person assisting for 
step 9. One person can unplug the CRT socket 
connector and ground wire, while the other person 
holds the CRT/Yoke Assembly firmly. 
10. After verifying that all cables are out of the way, 
remove the CRT/Yoke Assembly from the projector. 
11. Reinstall the CRT/Yoke Assembly in the reverse order. 
NOTE: When reinstalling the CRT/Yoke Assembly, 
plug the CRT ground wire into the CRT Socket 
Connector first, then partially plug in the Green socket 
connector into the CRT. When the CRT is completely 
installed it will be easier to fully insert  the CRT into the 
socket connector. 
12. Perform a CRT Mechanical focus adjustment (Section 
3.5) and CRT Rotation (Section 3.6) after replacing the 
CRT/Yoke Assembly. Check the CRT Mechanical 
Focus on the other two colors to verify that they are still 
correct. It is possible the other focus adjustments could 
have been disturbed by the removal and replacement 
of the CRT/Yoke Assembly. 
4.16   ILA® Assembly 
To remove an ILA® Assembly: 
1.   Remove the rear cover (Section 4.2). 
2.   Tilt up the Electronic Module (Section 3.3). 
3.   Disconnect the connector on the top of the appropriate 
ILA® assembly. (Figure 4-11). 
 
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							 Chapter 4---Maintenance (Removal/Replacement) 
 
Figure 4-12.  ILA® Assembly top view. The overlap screws shown are 
visible after the ILA® assembly is removed. 
4.   Loosen the two wingnuts at the top of the appropriate 
ILA® assembly (Figure 4-12). 
5.   Slide the spring clip at the top of the ILA® assembly 
backward (Figure 4-12). This will free the ILA® 
assembly. 
6.   Grasp the ILA®  assembly by its housing and slide it 
out.  
7.   Replace the ILA® in the reverse order from above. 
8.   Recheck convergence, shading, ILA® bias and G2 and 
readjust, if necessary (User’s Guide, Sections 5.8, 
5.10, 5.7, 5.9). 
9.   Recheck the ILA® Back Focus (Section 3.4) and the 
ILA® Overlap adjustment (Section 3.8). 
4.17   Relay Lens 
To remove a Relay Lens (refer to Figure 4-11): 
1.   Remove the rear cover (Section 4.2). 
2.   Tilt up the Electronic Module (Section 3.3) 
3.   Remove the corresponding CRT Assembly behind the 
Relay Lens that is to be removed. 
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							Chapter 4---Maintenance (Removal/Replacement) 
4.   Loosen the CRT Lens Stopper Ring (the thin collar just 
in front of the CRT Holder knurled ring-Figure 4-11) 
and slide it off the back of the Relay Lens. 
5.   Loosen the wing nut on top of the Relay Lens mount 
(the bracket at the rear of the Relay Lens). 
6.   Remove the 2 long hex bolts at the front of the Relay 
Lens (shown in Figure 4-12). 
7.   Remove the 2 hex bolts at the rear of the Relay Lens 
(these bolts are level with the bottom of the Relay Lens 
and hold the bracket in place). 
8.   Remove the Relay Lens. Leave the Relay Lens 
Bracket and the CRT Lens Stopper Ring in the 
projector-do not send them back with the Relay Lens. 
9.   Replace the Relay Lens in reverse order from above. 
4.18   Projection Lens 
To remove the Projection Lens: 
1.   Remove the sponge cover from around the front of the 
Projection Lens. 
2.   Disconnect and label the Projection Lens Focus and 
Zoom motor cables (The Focus motor is at the top of 
the Projection Lens. The Zoom motor is at the bottom.) 
3.   Loosen (do not remove) the Lens holding screw at the 
right side (Figure 4-13) of the Projection Lens. 
4.   Rotate the Projection Lens left or right so that the notch 
on the lens clears the holding screw on the lens holder 
(Figure 4-12). CAUTION! The lens can fall out now! 
Carefully slide the lens out.  
 
Figure 4-13.   Projection Lens holding screw and removal notch. 
5.   Replace the Projection Lens in reverse order. NOTE: 
The same basic procedure above is used to install or 
remove optional fixed lenses. 
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							 Chapter 4---Maintenance (Removal/Replacement) 
NOTE: When changing from a zoom to a fixed lens, or vice 
versa, the ILA® Back Focus (Section 3.4) may need 
readjustment. 
4.19   Prism Assembly 
CAUTION! The removal of the Prism Assembly 
requires removing the Dichroic Mirror Assembly (X-Plate). In most 
cases this necessitates an optical realignment. HJT does not 
recommend performing this replacement in the field. Optical 
alignment is critical and requires projector power to be on. This 
results in an additional safety hazard due to the high intensity light 
beam emanating from the optical area with the optical cover off. If 
removal and replacement is absolutely necessary, proceed with 
extreme caution and wear safety glasses. 
The Prism Assembly requires removing more components and 
assemblies than any other assembly. Be sure to have storage 
cabinets or tables to house the items as they are removed to 
provide access to the Prism Assembly. Allow 2-4 hours to perform 
the removal and replacement of the Prism Assembly. Refer to 
Figures 4-1 and 4-11 for assemblies referenced in this procedure. 
To remove the Prism Assembly: 
1.   Remove front and rear covers (Section 4.2). 
2.   Remove the Optical Shield (4 screws). 
3.   Remove the lower right side panel (5 screws). 
4.   Remove the Arc Lamp Base Assembly (arc lamp, 
ignitor, laser power supply, and blower). First, 
disconnect the Ignitor cables from the ALPS (J74) and 
the fan cables from the Arc Lamp fan and blower. Then 
remove the screws holding the base assembly (see  
Fig 4-14). 
5.   Remove the Dichroic Mirror assembly by removing the 
last hex bolt (Figure 4-14). Use care when lifting the 
mirror assembly. Place it in a safe, level storage area.  
6.   Remove the 2 hex bolts from the front of the Prism 
assembly (Figure 4-15). 
7.   Remove the Rollbar assembly (2 pozidrive bolts/nuts 
on left side and two nuts on right side). Disconnect and 
label the 2 connectors on the hinge assembly for the 
shutter motors (1 in front and 1 in rear). Remove and 
label the jumper that connects the front interlock switch 
to the rear interlock switch. 
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							Chapter 4---Maintenance (Removal/Replacement) 
8.   Remove the Rollbar Bracket that was holding up the 
left side of the Rollbar assembly. 
9.   Remove the 3 ILA® asssemblies (Section 4.15). 
 
Figure 4-14.   Dichroic Mirror Assembly. 
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							 Chapter 4---Maintenance (Removal/Replacement) 
 
Figure 4-15.   Prism Assembly mount. 
10. Remove the remaining three hex bolts from the rear of 
the Prism assembly. These screws are located in the 
cavities where the ILA® assemblies were removed (see 
Figure 4-15). 
11. The Prism is now free to be removed. 
CAUTION! The Prism assembly is 
heavy (about 70 lbs). Use two people to lift it out of the 
projector. 
12. Replace the Prism assembly in the reverse order. 
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							Chapter 4---Maintenance (Removal/Replacement) 
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							Chapter 5---Troubleshooting 
5.0  Troubleshooting 
Contents 
5.1   Status LEDs........................................................................\
.....5-1 
5.2   Error Codes........................................................................\
......5-4 
5.3   Troubleshooting Guide.............................................................5-6 
 
5.1   Status LEDs 
The illustrations below indicate where various LEDs are located that ind\
icate 
proper or improper operation of the System Controller, the Raster Timing\
 
Generator, the Video Processor Board, the Scan Reversal Board, the 
Convergence/Deflection Board, the Video Amplifier Board, the Low Voltage\
 
Power Supply, and the High Voltage Power Supply.  
 
Figure 5-1.   Projector rear with cover and rear panel off. 
Model 220 Service Manual  5-1