Hughes JVC Projector 250 Sc Service Manual

							Chapter 4---Optical
4-18 
Model 250 Service Manual
  WARNING!!! Always wear an ANSI/ASTM 10,000
volt rated safety glove when working around CRTs due to the High
Voltage present there.
NOTE:
 If the ILA®/Relay Lens/CRT assembly cannot be moved close
enough to get a good spacer ball focus, loosen the CRT Lens Stopper Ring
in front of the CRT Holder Ring using a 2.5-mm Hex wrench. Move the
CRT snug against the collar to get additional range, and then, retighten the
collar.
10. Using the 4-mm hex-head wrench, loosen the two hex bolts (see Figure
4-10) on the ILA
® assembly in front of the Relay Lens.
11. Slide the Relay Lens/CRT/ILA
® assembly forward or backward to achieve
the sharpest spacer ball focus.
NOTE:
 Do not use the zoom lens focus while performing this step.
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 9-13 for other colors that need ILA
® Back Focusing. Be sure
to hide the other two colors.
To adjust the ILA
® Back Focus for a Fixed Lens:
1. Power the projector ON and allow it to stabilize for 15 minutes.
2. Remove the rear cover and tilt up the Electronic Module.
3. View Green. Hide Red and Blue.
4. Select the Focus Pattern (Test Pattern #6).
5. Select Projection Lens from the menu.
6. Use left and right arrows to focus the projection lens to get sharply
focused spacer balls.
7. Put on safety gloves (see Safety section for gloves type) then loosen the
wing nut on the Green Relay Lens, (or whichever lens is being focused).
NOTE:
 If the ILA
®/Relay Lens/CRT assembly cannot be moved close
enough to get a good spacer ball focus, loosen the CRT Lens Stopper Ring
in front of the CRT Holder Ring using the 2.5-mm Hex wrench. Move the
CRT snug against the collar to get additional range, then retighten the
collar. 
						

							Chapter 4---Optical
Model 250 Service Manual 4-19
8. Loosen the two hex bolts (see Figure 4-10) on the ILA® assembly in front
of the Relay Lens.
9. Slide the Relay ILA
®/Lens/CRT assembly forward or backward to achieve
the sharpest spacer ball focus.
NOTE:
 Do not use the projection lens focus while performing this step.
10. Tighten the hex bolts on the Green ILA
® Assembly and the wing nut on
the Green Relay Lens.
11. Repeat Steps 7-10 above for other colors that need ILA
® Back Focusing.
Be sure to hide the other two colors.
ILA
® Remove and Replace
Each projector has three ILA®s; each located on the front of a Relay Lens.
Tools Needed
4-mm Hex wrench
Parts Needed
Super Contrast
Blue   102630-14 
Green   102630-15
Red   102630-16
NOTE:
  Do not interchange Super Contrast ILA
®s. The Compensators on the
ILA®s are color specific and can not be interchanged i.e. the green ILA® can not
be put in the red channel or blue channel.
To Remove the ILA
®
1. It is not necessary to power off the projector.
2. Remove the Rear cover. It is not necessary to tilt the Electronics Module
up.
3. Loosen the two Hex nuts using a 4-mm Hex nut wrench and slide the
ILA®/Relay Lens/CRT Assembly back.
4. Loosen the two wing nuts on the ILA® and pull back the spring clip.
5. Disconnect the connector from the ILA® and remove the ILA® assembly
(it will slide out with some resistance).
It will be necessary to reset ILA
® bias, and Overlap. ILA® Compensator, G2
setting, and shading for the ILA® being replaced should be checked. 
						

							Chapter 4---Optical
4-20 
Model 250 Service Manual
4.4 Relay Lenses
The Relay Lens focuses the image light received from the CRT on the
photoconductive layer of the ILA® (see Figure 4-9). There are no service
adjustments for the Relay Lens. The Relay Lens rarely needs service and is not
considered a serviceable part.
4.5 Projection Lens
Projection Lens  - Input
Combined RGB image light from the Prism Assembly.
Projection Lens  - Output
Output image light to the screen
Projection Lens  - Operation
The projection lens receives image light from the Prism Assembly. The light is
high intensity light from the ILA® that has been modulated by the image light
from the CRT. After leaving the ILA®s the modulated light travels back through
the Prism Assembly where the red, green, and blue image light are combined. The
Projection Lens focuses this output image light onto the screen. All Projection
Lenses come with motorized focus adjustment.
The Model 250 projector comes with a choice of four standard lens options.
Motorized Zoom Lens
2:1 - 4:1
!
 Fixed Lenses
0.96: 1
1.5: 1
5.6:1
!
 Optional Lenses
2.4:1 Simulator Lens
Projection Lens  - Service Adjustments
There are no service adjustments for the Projection Lens. The focus adjustment,
both rough and fine focus adjustments, are part of the projector setup procedure
(see Model 250 User’s Guide, Setup Adjustments sections 5.4 and 5.5.15)
Projection Lens  - Remove and Replace
Tools Needed
5-mm Hex wrench
To remove the Projection Lens:
1. Remove the sponge cover that is 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.) 
						

							Chapter 4---Optical
Model 250 Service Manual 4-21
3. Loosen (do not remove) the Lens holding screw at the right side (see
Figure 4-11) of the Projection Lens.
Figure 4-11   
Projection Lens holding screw and removal notch.
NOTE: 
The 0.96:1 Projection Lens has an adapter sleeve installed on
it. The Projection Lens is installed the same as other Projection Lenses
except the Holding Bolt needs to be loosened more to allow the
Projection Sleeve to clear it.
4. Rotate the Projection Lens left or right as needed so that the notch on the
lens clears the holding screw on the lens holder (see Figure 4-11).
5. Carefully pull the Projection Lens out of the projector.
6. Replace the Projection Lens in reverse order. Be sure to reconnect the
Zoom and Focus motor cables.
NOTE:
 Use the same procedure to install or remove fixed lenses. Also,
when changing from a zoom to a fixed lens, or vice versa, check the ILA
®
Back Focus adjustment (see section 4.3 ILA®). 
						

							Chapter 5 Optical
3-4-22 
Model 100 Service Manual 
						

							Chapter 5---Electronics
Model 250 Service Manual 5-1
5.0 Electronics
Contents
5.1  Safety............................................................................................................ 5-1
5.2  Introduction .................................................................................................. 5-2
5.3  System Controller PCB ................................................................................ 5-3
5.4  Video Processor PCB ................................................................................... 5-11
5.5  Raster Timing Generator PCB ..................................................................... 5-16
5.6  Horizontal Vertical Deflection PCB ............................................................ 5-21
5.7  Convergence Deflection PCB ...................................................................... 5-28
5.8  Scan Reversal PCB....................................................................................... 5-34
5.9  Video Amplifier PCB ................................................................................... 5-43
5.10 CRT/Yokes .................................................................................................. 5-51
5.11 VICs ............................................................................................................ 5-58
Standard RGBHV VIC ............................................................................... 5-59
Graphics Enhancer Plus VIC...................................................................... 5-61
4-Input (Quad) RGBHV VIC ..................................................................... 5-64
YPbPr VIC ................................................................................................. 5-67
Quad Standard Decoder VIC...................................................................... 5-70
Quad Standard Decoder/Line Doubler VIC ............................................... 5-72
5.12  Backplane PCB .......................................................................................... 5-74
5.1 Safety
  CAUTION!  Before performing procedures in this chapter,
review the chapter on Safety at the beginning of this manual
.
 WARNING!!! When performing procedures in this chapter
that require projector covers to be removed, wear high voltage gloves
(ANSI/ASTM 10,000 volt rated) when working near the CRTs, Arc Lamp,
or power supplies. Wear safety goggles (rated X5) when working
anywhere
 near the light path from the arc lamp or the projection lens. 
						

							Chapter 5---Electronics
5-2 Model 250 Service Manual
 WARNING!!!
 Never look directly at the Arc Lamp, the
lighted Projection Lens or into the lamp housing, from any distance, when
the projector is on. Direct exposure to light of this brightness can cause
severe eye injury.
5.2 Introduction
The Model 250 Electronics System includes nine printed circuit assemblies. They
provide all the controlling voltages and signals to adjust and correct picture
settings, geometry, convergence, and shading (see Chapter 4 of the User’s
Guide). The Electronics System also controls video and sync input signals, LED
displays on PCBs at the rear and side of the projector, two RS-232
communications ports, and two IR receivers for remote control of the projector.
The descriptions in this portion of the manual are based on an overall Electronics
System block diagram and simplified block diagrams for each of the nine printed
circuit assemblies.
Figure 5-1 provides an overall System Block Diagram to show how the Optical
System, Arc Lamp, and Electronics System combine to provide the bright screen
image.
Figure 5-1  
Model 250 System Block Diagram. 
						

							Chapter 5---Electronics
Model 250 Service Manual 5-3
Figure 5-2   
Model 250 Electronics Module with PCBs (side view).
  CAUTION!
  It is very strongly recommended that setup
data be downloaded (
Exported, see section 8.2 Importing/Exporting) before
performing any of the following procedures. Exporting baseline source
setup data to disk is an excellent precautionary measure. It will save the
time of setting up new source file(s) in the case of an unexpected problem
.
5.3 System Controller PCB
System Controller PCB - Main Function
!
 Enables control for the Low Voltage Power Supply, Arc Lamp and
cooling fans.
!
 Fault monitors the HVPS, LVPS, Arc Lamp, and fans.
!
 Provides IIC serial bus communication and control between PCBs.
!
 Controls Zoom and Focus of the Projection Lens.
!
 Generates Menu and Internal Patterns Overlays
!
 X and Y Convergence control
!
 Threshold and Sensitivity for shading 
						

							Chapter 5---Electronics
5-4 Model 250 Service Manual
!
 I/O control for VIC selection
!
 Two RS-232 serial interface ports
!
 Infrared (IR) remote control interface. Accepts input from front or rear IR
detectors.
!
 External 3 color system status LEDs. Green indicates normal, yellow is
standby and red indicates a fault condition.
!
 External Service Mode Switch. Pressing this switch during a power-up
sequence brings the system up in a diagnostic mode (for maintenance)
rather than a normal operating mode.
Figure 5-3  
Rear of Electronics Module with rear cover and panel removed. 
						

							Chapter 5---Electronics
Model 250 Service Manual 5-5
Figure 5-4  
System Controller PCB I/O Diagram for Power Supplies and peripherals.