Prism Assembly - Hughes JVC 220 Service Manual

4.19 Prism Assembly

Model 220 Service Manual
Chapter 4---Maintenance (Removal/Replacement)
NOTE: When changing from a zoom to a fixed lens, or vice
versa, the ILA
readjustment.
CAUTION!
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 safety glasses.
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 4-11 for assemblies referenced in this procedure.
To remove the Prism Assembly:
1. Remove front and rear covers (Section 4.2).
2. Remove the Optical Shield (4 screws).
3. Remove the lower right side panel (5 screws).
4. Remove the Arc Lamp Base Assembly (arc lamp,
ignitor, laser power supply, and blower). First,
disconnect the Ignitor cables from the ALPS (J74) and
the fan cables from the Arc Lamp fan and blower. Then
remove the screws holding the base assembly (see
Fig 4-14).
5. Remove the Dichroic Mirror assembly by removing the
last hex bolt (Figure 4-14). 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 4-15).
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.
®
Back Focus (Section 3.4) may need
The removal of the Prism Assembly
4-23