Hughes Jvc 220 Projector Service Manual

							Chapter 4---Maintenance (Removal/Replacement) 
 
Figure 4-4.  Ignitor Assembly and Arc Lamp Power Supply 
4.6  Arc Lamp Power Supply 
To remove the Arc Lamp Power Supply: 
1.   Remove the front cover (Section 4.2). 
2.   Remove the lower-right-front-side panel by removing 
the 5 pozidrive screws securing it. 
3.   Remove the 2 pozidrive screws from the bottom of the 
EMI shield and slide it out of the way to the left. 
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							 Chapter 4---Maintenance (Removal/Replacement) 
 
Figure 4-5.  Arc Lamp Power Supply connections. 
4.   Remove and label the cables from the DC OUTPUT 
terminal, J74 (see Figure 4-5 for cable connections).  
5.   Disconnect J71 (AC Input). 
6.   Disconnect J72 (SIGNAL CABLE). 
7.   Disconnect J73. 
8.   Remove the 2 screws at the bottom of the ALPS and 
carefully slide it out of the projector. 
9.   Replace the Arc Lamp Power Supply in reverse order 
from above. NOTE: When replacing the cables on the 
± terminals on J74, a mechanical pickup tool is very 
useful to start the screws.  
10. Perform the Arc Lamp Focus, Alignment, and Current 
Setting procedures as shown in Section 3.1 and 3.2. 
4.7  Low Voltage Power Supply 
To remove the Low Voltage Power Supply: 
1.   Remove the front cover. 
2.   Remove the lower-right-side panel by removing the 5 
pozidrive screws securing it. 
3.   Remove the 2 pozidrive screws securing the EMI 
Shield. Slide the shield to the left and remove it. 
4.   Remove J76 (DC Output) and J75 (AC Input) from the 
left side of the Low Voltage Power Supply. NOTE: 
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							Chapter 4---Maintenance (Removal/Replacement) 
These connectors may be difficult to remove and it may 
be necessary to angle the LVPS partly out of the 
chassis in order to get a firmer grip on the connectors. 
5.   Remove the 2 screws on the bottom side of the LVPS 
and carefully slide it out of the projector. 
6.   Reinstall the LVPS in reverse order. After the LVPS is 
installed, recheck Timing, Geometry, Electronic Focus, 
ILA® Bias/Sensitivity, Convergence, G2, and Shading. 
4.8  High Voltage Power Supply 
To remove the High Voltage Power Supply: 
1.   Remove the front and rear covers (Section 4.2). 
2.   Remove the High Voltage Power Supply cover (Figure 
4-5) by removing the 2 pozidrive screws that secure 
the HVPS at the top of the cover and loosening the 1 
pozidrive screw at the bottom of the front flap (Do not 
remove this bottom screw-it is difficult to reinstall. The 
HVPS will slide up and over it). 
 
Figure 4-5.    High Voltage Power Supply cover. 
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							 Chapter 4---Maintenance (Removal/Replacement) 
 
Figure 4-6   High Voltage Power Supply. 
3.   Carefully slide the cover upward and outward to 
remove it. 
NOTE:  For the remainder of this procedure refer to Figure 
4-6 above. 
4.   Disconnect the 3 CRT anode cables. 
5.   Disconnect P44-G2 Out (at the middle-front of the 
HVPS). 
6.   Unsnap the cable clamp at the top of the HVPS. 
7.   Remove the anode cables and the P44 cable from the 
cable clamp. 
8.   Disconnect P45 (“Control”) at upper left of HVPS. 
9.   Disconnect and label the 3 Focus cables. The square 
tabs on these cables (see Figure 4-6) may have to be 
lifted up by gently prying with a flathead screwdriver. 
10. Remove all cables from the slot in the cable guide at 
the left side of the HVPS. 
11. Verify that all plugs and cables are removed and out of 
the way so the HVPS is free to be removed. 
12. Loosen (do not remove) the 2 pozidrive screws (at the 
bottom of the HVPS) that secure the HVPS metal 
housing to the projector. 
13. Remove the 2 pozidrive screws that hold the top of the 
HVPS metal housing to the projector frame. 
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							Chapter 4---Maintenance (Removal/Replacement) 
14. Grasp the HVPS at the bottom and lift upward and 
outward so that it slides away from the bottom screws. 
15. Reinstall the HVPS in the reverse order from above. 
When reinstalling, be sure that the HVPS slides over 
the bottom screws and the lip at the top of the projector 
frame. Make sure each anode cable “snaps” back into 
its receptacle. The receptacles are about 2” inside the 
hole where the cable fits into. Also, be sure the rear 
flap on each focus cable connector snaps over the 
square socket securely-wiggle the connector a little to 
make it fit over. 
16. Replace the HVPS cover. After the HVPS is replaced, 
recheck CRT Mech Focus, Yoke Alignment, G2, and 
Electronic Focus.  
17. Replace the projector covers. 
4.9  Raster Timing, System Controller, Video Processor 
PCBs 
All electrical connections to the Raster Timing Generator, System 
Controller, and Video Processor boards are routed through the 
backplane board. There are no connectors to remove. 
To remove the Raster Timing Generator, Video Processor, or 
System Controller PCBs: 
1.   Turn off power at the remote control and at the circuit 
breaker on the projector rear panel. 
2.   Remove the projector rear cover. 
3.   For the Raster Timing Generator and Video Processor 
PCBs, grasp the card extractor tabs at both ends of the 
boards and pull out. To remove the System Controller 
Board, use a small, flathead screwdriver and remove 
the screw in the bracket in the center of the System 
Controller Board (this bracket holds the SCB to the 
card cage). Grasp the bracket and pull out the SCB. 
4.   When replacing boards, verify that power is off at the 
circuit breaker, the power plug is disconnected and 
there are no bent pins on any connectors. Make sure 
the board is properly and securely seated before 
reapplying power. 
 
NOTE: To remove connectors on the printed circuit boards in the 
sections below, push the connector in slightly, then squeeze the 
tab and pull the connector out. 
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							 Chapter 4---Maintenance (Removal/Replacement) 
4.10  Convergence/Deflection PCB. 
The Convergence/Deflection PCB is located on the bottom side of 
the Electronic Module card cage. 
To remove the Convergence/Deflection PCB: 
1.   Remove the rear cover (Section 4.2). 
2.   Tilt the Electronic Module up. (Section 3.3). 
3.   Disconnect 6 connectors; J31, J32, J33, J38, J39, and 
J40. (Figure 4-6). Move the cables out of the way. 
 
Figure 4-7.   Convergence/Deflection PCB. 
4.   Loosen (not necessary to remove) the 5 screws that 
secure the Convergence Deflection PCB to the 
electronic module card cage (see Figure 4-7).  
5.   Remove the Convergence Deflection PCB by sliding it 
upward so the mounting screws will clear the access 
holes, then angle the right side outward. NOTE: In 
order to get the right side out, it may be necessary to 
first move the board out enough to clear the access 
holes, then angle the left side out just enough for the 
top 2 fins of the heat sync to fit over the electronic 
module frame lip (this will allow a little more clearance 
for the right side to be removed), then maneuver the 
right side out. 
6.   Reinstall the Convergence/Deflection PCB by lowering 
the right side in first  until it clears the electronic 
module edge, then lowering the left side in. NOTE: it 
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							Chapter 4---Maintenance (Removal/Replacement) 
may be necessary to fit the top 2 fins of the heat sync 
over the electronic module frame lip at the left to get 
enough clearance for the right side to be installed. 
Carefully fit the board over the mounting screws and 
slide the board into position. Tighten the screws and 
reconnect the connectors. 
4.11   Horizontal/Vertical Deflection PCB 
The Horizontal/Vertical (H/V) Deflection PCB is located in the 
upper portion of the Electronic Module card cage. 
To remove the Horizontal/Vertical (H/V) Deflection PCB: 
1.   Remove the rear cover (Section 4.2). 
2.   Disconnect 6 connectors; J34, J35, J36, J41, J42, and 
J43. (see Figure 4-8). Move the cables out of the way. 
3.   Loosen (not necessary to remove) the 5 pozidrive 
screws that secure the H/V Deflection Board to the 
electronic module cage.  
4.   Remove the H/V Deflection PCB by sliding it toward 
the left side of the projector (this is the upward direction 
if the electronic module is raised up) so that the 
mounting screws clear the access holes. Then lift the 
side of the board that is nearest the front of the 
projector first and angle it upward so that the side 
closest to the rear clears the lip of the electronic 
module frame. Be careful when removing or reinstalling 
the board to avoid gouging it on the fan screws or 
cable clamps. 
5.   Reinstall the HV Deflection PCB by lowering the side 
that is nearest to the rear of the projector in first until it 
clears the electronic module edge, then lowering the 
other side. Carefully fit the board over the mounting 
screws and slide the board into position. Tighten the 
screws and reconnect the connectors. 
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							 Chapter 4---Maintenance (Removal/Replacement) 
 
Figure 4-8.   Horizontal/Vertical Deflection PCB. 
4.12   Video Input Cards (VICs) 
The 4 types of Video Input Cards, RGB Standard, 4X RGB Mux (4 
RGB Input), Quad Decoder, and HDTV (YPbPr) are all removed 
and inserted in the same manner.  
To remove a VIC: 
1.   Disconnect all video input connections from the VIC to 
be removed. 
2.   Remove the 2 flathead screws that secure the VIC to 
the projector rear panel. 
3.   Grasp the VIC connector bracket and pull the VIC out 
(Wiggle the VIC a little, if necessary, to extract it). 
4.13   Video Amplifier PCB 
The Video Amplifier PCB for the 3 CRTs is located under the 
Electronic Module, on the bottom frame of the projector behind 
and under the CRT assemblies. 
To remove a Video Amplifier PCB: 
1.   Remove the front and rear covers (Section 4.2). 
2.   Tilt the Electronic Module up (Section 3.3). 
3.   Loosen the Green CRT Holder Ring (knurled knob-see 
Figure 3-5). Read the Caution below this step before 
removing the CRT Holder Ring completely. NOTE: The 
holder ring should only be hand-tight. If it cannot be 
removed by hand, a flathead screwdriver can be used 
in the slots on the CRT Holder Ring (Figure 3-5) to help 
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							Chapter 4---Maintenance (Removal/Replacement) 
loosen it. Use care not to let the flathead screwdriver 
slip out of the slot and possibly damage components. 
Do not use a screwdriver or any other tool to tighten 
this ring-it should be hand-tight only.  
CAUTION! This step is performed with the CRT Socket 
Connector still connected to the Green CRT and the 
ground wire still connected from the CRT/Yoke Assembly 
to the CRT Socket Connector. This is because the Green 
CRT 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 of the projector. Use extreme care not to break any of 
these connections when removing the CRT/Yoke 
Assembly.  
4.   Carefully remove the Green CRT/Yoke Assembly by 
sliding it backward and upward as far as possible 
before disconnecting the Green CRT Socket Connector 
from the CRT neck. Use care to avoid bumping the 
CRT as it is being removed and to avoid breaking any 
of the wires that connect from the CRT Socket 
Connector to the Video Amplifier. 
5.   Move the Green CRT/Yoke Assembly away from the 
rear of the projector, then disconnect the Green CRT 
Socket Connector and the ground wire between the 
CRT/Yoke Assembly and the CRT Socket Connector. 
NOTE: It may be helpful to perform this step with a 
partner-one person to hold the CRT/Yoke Assembly 
firmly and the other to remove the CRT Socket 
Connector and the ground wire. 
6.   Gently lay the Green CRT Socket Connector on the top 
of the Video Amplifier PCB. 
7.   Place the Green CRT Assembly in a safe location on 
or against one of the other CRT Assemblies. 
8.   Disconnect the Red and Blue CRT Socket Connectors 
and gently lay them on the top of the Video Amplifier 
Board. 
9.   Disconnect the 3 connectors (push in slightly, squeeze 
the tabs, and pull out), J67, J68, and J69 from the 
Video Amplifier PCB. Move the cables out of the way. 
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							 Chapter 4---Maintenance (Removal/Replacement) 
 
Figure 4-9.   Video Amplifier PCB showing breakaway CRT Socket 
Connectors. 
10. Disconnect the 3 Focus cables that run from the CRT 
Socket Connectors to the Focus connectors on the 
HVPS. NOTE: Observe that each of the 3 Focus 
cables (large, red wires that run from each CRT Socket 
Connector to the Focus connectors on the HVPS) is 
joined near the CRT by a coupler plug and jack. 
Disconnect (and label) the focus cables at these 
couplers. 
11. Loosen the 6 pozidrive screws that secure the Video 
Amplifier PCB to the projector frame. 
12. Make sure everything is out of the way, then slide the 
Video Amplifier PCB toward the left so the mounting 
screws will clear the access holes and remove the 
board from the projector.  
13. Reinstall in the reverse order from above. NOTE: The 
Video Amplifier PCB is shipped with the 3 CRT Socket 
Connectors attached at the end in a “breakaway” 
arrangement (Figure 4-9). Use a pair of diagonal 
cutters and carefully cut the socket connectors away 
from the Video Amplifier PCB. The spacers between 
the CRT Socket Connectors can be discarded. 
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