JVC 250 service manual Relay Lenses, Projection Lens

Chapter 4---Optical

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.)

4-20 Model 250 Service Manual