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...

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...

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...

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...

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...

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...

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...

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...

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