Hughes Model 230 Projector Service Manual

							Chapter 4---Maintenance (Removal/Replacement)
Model 230 Service Manual4-5
the fans to cool the Arc Lamp. The power interlock switches for both covers
are attached to each cover hinge.
5.   When the Latch Levers are inserted into the holding slots, lift the cover off.
Be careful not to brush against any of the internal components of the
projector when removing the cover. If any undue resistance is felt, stop to
locate the source before proceeding.
6.   Replace the covers in reverse order from above. When replacing either
cover, make sure the slot in the cover fits over the bottom of the projector
case or the cover will not close correctly.
4.3  Air Filters
Air filters should be cleaned whenever necessary. In extremely dusty or dirty
conditions, the filters should be cleaned more frequently. Remove the filters and
vacuum them or blow them clean with compressed air. They may also be
washed with soap and water.
There are 3 polyurethane air filters in the Model  230 that require periodic
cleaning. They are located as follows:
•  1 metal-framed filter in the rear of the projector in the bottom cover-
accessible when the rear cover is off.
•  1 filter on the bottom of the projector-slides out from the middle-left side of
the projector (grasp the hole in the filter frame). The filter can be peeled off
the Velcro on the frame, if necessary.
•  1 metal-framed filter in the front-left-bottom cover accessible with the front
cover off.
4.4  Arc Lamp Assembly
The Arc Lamp Enclosure Assembly consists of a the Xenon Arc Lamp module
and blower. The blower is removed and replaced together with the Arc Lamp
Module.
Caution: It is strongly recommended that the Arc Lamp current be turned down
(see Section 3.1) before installing a new Arc Lamp to help prevent possible
damage that could reduce the life of the new lamp.
 WARNING!!! Dangerous light exists in this area of the projector.
Before proceeding with the removal of any subassemblies below, verify that the
circuit breaker at the rear of the projector is turned off and the power plug is
removed from the AC outlet.
To remove the Arc Lamp Enclosure Assembly:
1.   Remove the front cover (Section 4.2).
2.   CAUTION! Ensure all fans have stopped running. 
						

							Chapter 4---Maintenance (Removal/Replacement)
4-6Model 230 Service Manual
3.   Remove the lower-right-front-side panel (5 screws).
4.   Remove the Dichroic Shield (1 screw on top-connects to Arc Lamp
enclosure, 1 screw in front-connects to Arc Lamp enclosure, 1 screw on
bottom-right-connects to Ignitor board).
Figure 4-3.   Arc Lamp Assembly
5.   Disconnect the Arc Lamp blower cable.
6.   Disconnect the Arc Lamp fan cable. This cable is routed through the bottom
of the Arc Lamp assembly enclosure (below the right side in Figure 4-3) and
provides power to the Arc Lamp door fan through the white socket shown to
the right of the Arc Lamp fan in Figure 4-3. Disconnect the cable at the
socket connection below the Arc Lamp enclosure.
Arc Lamp fan
cable is routed in
through the
bottom of the Arc
Lamp enclosure
and provides
power to this
socket. Step 6.
Arc Lamp
Blower 
						

							Chapter 4---Maintenance (Removal/Replacement)
Model 230 Service Manual4-7
Figure 4-4.   Arc Lamp cable and clamp.
7.   Label and disconnect both Arc Lamp cables from the Ignitor board (Figure 4-
5). These are called out as Positive Common and Negative Output in
Figure 4-5. Return these cables with the Arc Lamp assembly
8.   Remove the two holding bolts that secure the Arc Lamp Enclosure to the
projector (Figure 4-4).
9.   Carefully slide the Arc Lamp assembly out.
9.   Reinstall the Arc Lamp in reverse order from above.
10. After reinstalling the Arc Lamp, perform the Arc Lamp adjustment procedure
as shown in Chapter 3.
4.5  Ignitor Assembly
The Ignitor Assembly includes the Ignitor and the Laser Power Supply. When
either of these two components require replacing, the Ignitor Assembly is
returned and replaced as a unit.
To remove the Ignitor Assembly:
1.   Remove the front cover (Section 4.2).
2.   Disconnect and label the cables attached to the Ignitor (see Figure 4-5).
3.   Remove the 3 screws securing the Ignitor Assembly (refer to Figure 4-5).
4.   Replace the Ignitor Assembly in reverse order.
Holding bolts. 
						

							Chapter 4---Maintenance (Removal/Replacement)
4-8Model 230 Service Manual
Figure 4-5.   Ignitor Assembly.
4.6  Arc Lamp Power Supply
To remove the Arc Lamp Power Supply:
 CAUTION!It is strongly recommended that the Arc Lamp
current be turned down (see Section 3.1) before installing a new Arc Lamp to
help prevent possible damage that could reduce the life of the new lamp.
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.
NEGATIVE
INPUT
Positive
Common.
Disconnect to
remove the Arc
Lamp assembly
Negative Output.
Disconnect to
remove the Arc
Lamp assembly.
Remove these
three screws to
remove Ignitor
Assembly. 
						

							Chapter 4---Maintenance (Removal/Replacement)
Model 230 Service Manual4-9
Figure 4-6.  Arc Lamp Power Supply connections.
4.   Label and remove the cables from the DC OUTPUT terminal, J74 (see
Figure 4-6 for cable connections). Retain the .47µfd capacitor, connected
across the terminals, to be reinstalled on the replacement power supply.
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 Adjustment procedure as shown in Section 3.1.
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: These connectors could be a little difficult to 
						

							Chapter 4---Maintenance (Removal/Replacement)
4-10Model 230 Service Manual
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 4-7) by removing the
pozidrive screw that secures the HVPS at the bottom of the cover and
loosening the 2 pozidrive screws at the top of the front flap.
Figure 4-7.    High Voltage Power Supply cover. 
						

							Chapter 4---Maintenance (Removal/Replacement)
Model 230 Service Manual4-11
Figure 4-8   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 4-8 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 4-8) 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.
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 
						

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4-12Model 230 Service Manual
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 (for these PCB locations, refer to Figure 4-9):
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, 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.
Figure 4-9.   Projector rear with cover and rear panel off. 
						

							Chapter 4---Maintenance (Removal/Replacement)
Model 230 Service Manual4-13
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.
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 from the
Convergence/Deflection PCB (Figure 4-10). Move the cables out of the way.
Figure 4-10.   Convergence/Deflection PCB.
4.   Loosen (not necessary to remove) the 5 screws that secure the
Convergence Deflection PCB to the electronic module card cage (Figure 4-
10).
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. 
						

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NOTE: it 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. (Figure 4-11).
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.