JVC Model 200 service manual Service Adjustments

Chapter 3 Service Adjustments

4.Select the Focus test pattern.

5.Select Projection Lens from the menu.

6.Use the up/down arrow keys to zoom the Projection Lens to full telephoto position (smallest image). NOTE: Skip this step when using an optional fixed lens.

7.Use left and right arrow keys to focus the projection lens to get sharply focused spacer balls. NOTE 1: Spacer balls are used inside the ILA® Assembly to separate the layers. They are tiny, random, irregularly-shaped spots that are visible throughout the image. Look directly in front of the screen in the lighter areas of the image to view. From throw distances shorter than 4 meters, spacer balls are difficult to see.

8.Zoom the lens to a wide angle position (largest image). NOTE: Skip this step when using an optional fixed lens.

9.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 (Figure 3-5). Move the CRT snug against the collar to get additional range, and then, retighten the collar.

10.Loosen the 2 hex bolts (Figure 4-12) on the ILA® assembly in front of the Relay Lens.

11.Slide the Relay Lens/CRT/ILA® assembly forward or backward until the sharpest spacer ball focus is achieved. 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 6-11 above for any other assembly needing ILA® Back Focusing. Be sure to hide the other 2 colors.

NOTE: The CRT Mechanical Focus procedure (Section 3.5) is often performed sequentially with the CRT Rotation procedure (Section 3.6). The same two set screws (Figure 3-5) are loosened when doing either of these procedures. When performing the procedures in sequence, ensure the two set screws are secure when either the focus lock screw or the CRT thumbscrew is tightened after finishing each adjustment. Do not leave the set screws loose when securing either the focus lock screw or the CRT thumbscrew. Turning

3-6 Model 200 Service Manual