Hughes Model 230 Projector Service Manual

							Chapter 4---Maintenance (Removal/Replacement)
Model 230 Service Manual4-15
Figure 4-11.   Horizontal/Vertical Deflection PCB.
4.12   Video Input Cards (VICs)
Instructions for installing, removing, editing and VIC Settings are covered in
Chapter 5 of the Model 230 Users Guide.
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 3.2).
3.   Loosen the Green CRT Holder Ring (knurled knob-see Figure 3-8). 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 3-8) to help loosen it. Be careful 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 
						

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4-16Model 230 Service Manual
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 )Figure 4-12). Move the
cables out of the way.
Figure 4-12.   Video Amplifier PCB showing breakaway CRT Socket
Connectors. 
						

							Chapter 4---Maintenance (Removal/Replacement)
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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 4-12). 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.
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 4-13.   Scan Reversal PCB.
2.   Disconnect 7 connectors (Figure 4-13); 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. 
						

							Chapter 4---Maintenance (Removal/Replacement)
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4.   Remove the 4 pozidrive screws (Figure 4-13) 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.
Three CRT/Yoke Assemblies are located in the CRT Assembly area below the
card cage. To remove a CRT/Yoke Assembly (refer to Figure 4-14):
Figure 4-14.   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 3-2).
3.   Remove the two pozidrive screws from the top of the High Voltage Power
Supply (HVPS) cover (Figure 4-7) and remove the one screw at the bottom
of the cover and loosen the two screws at the top of the cover.
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 4-13). 
						

							Chapter 4---Maintenance (Removal/Replacement)
Model 230 Service Manual4-19
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 3-8). 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 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 3.4) and CRT Rotation
(Section 3.5) 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 3-2). 
						

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3.   Disconnect the connector on the top of the appropriate ILA® assembly.
(Figure 4-14).
Figure 4-15.  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
4-15).
5.   Slide the spring clip at the top of the ILA
® assembly backward (Figure 4-15).
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 the ILA
® Back Focus (Section 3.3) and the ILA® Overlap
adjustment (Section 3.7).
9.   Recheck convergence, shading, ILA
® bias and G2 and readjust, if necessary
(User’s Guide, Chapter 5).
4.17   Relay Lens
To remove a Relay Lens (refer to Figure 4-14):
1.   Remove the rear cover (Section 4.2).
2.   Tilt up the Electronic Module (Section 3.2)
3.   Remove the corresponding CRT Assembly behind the Relay Lens that is to
be removed (refer to Section 4.15). 
						

							Chapter 4---Maintenance (Removal/Replacement)
Model 230 Service Manual4-21
4.   Loosen the CRT Lens Stopper Ring (the thin collar just in front of the CRT
Holder knurled ring-Figure 4-14) 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
4-15).
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-
16) 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 4-16). 
 CAUTION!
The lens can fall out now! Carefully slide the lens out.
Figure 4-16.   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.
NOTE: When changing from a zoom to a fixed lens, or vice versa, the ILA
® Back
Focus (Section 3.3) may need readjustment. 
						

							Chapter 4---Maintenance (Removal/Replacement)
4-22Model 230 Service Manual
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 proper safety glasses as outlined in the section on safety at the front of
this manual.
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 4-14 for assemblies referenced in this procedure.
To remove the Prism Assembly:
1.   Remove front and rear covers (Section 4.2).
2.   Remove the Dichroic Shield (3 screws).
3.   Remove the lower right side panel (5 screws).
4.   Remove the Arc Lamp Assembly (Section 4.4).
5.   Remove the Ignitor Assembly (Section 4.5).
5.   Remove the Dichroic Mirror assembly by removing the remaining hex bolts
(Figure 4-17). 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 4-17).
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.
8.   Remove the Rollbar Bracket that was holding up the left side of the Rollbar
assembly.
9.   Remove the 3 ILA
® asssemblies (Section 4.16). 
						

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Figure 4-17.   Dichroic Mirror Assembly.
Figure 4-18.   Prism Assembly mount. 
						

							Chapter 4---Maintenance (Removal/Replacement)
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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.
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.
4-20   Recommended Spares
It may be advisable to maintain a supply of spares for the projector to maximize
performance. This is particularly important when projectors are being operated
on a continuous basis or when multiple projectors are needed. Table 4-1, below,
provides a list of the spares that HJT recommends for one to four projectors.
Table 4-1.   Recommended minimum spares
PART NO. DESCRIPTION QUANTITY
102583 PCA Horiz/Vert Deflection 1
102581 PCA Conv/Defl 1
105232 PCA Video Amplifier 1
105234 PCA Video Processor 1
104678 PCA System Controller 1
102589 PCA Raster Timing Gen. 1
102585 PCA Scan Reversal 1
104413 PCA Graphics Enhancer VIC 1
102520 System Power Supply 1
102566 High Voltage Power Supply 1
104787 Arc Lamp Module 1-4