JVC Model 200 service manual ILA Overlap, RGB Electronic Focus adjustments

Chapter 3 Service Adjustments

Figure 3-6.RGB Electronic Focus adjustments.

3.8ILA® Overlap

This adjustment positions the ILA® assemblies in their sockets. Adjustment should only be made once or whenever an ILA® is replaced.

To determine if this adjustment is necessary:

1.Note the value of the ILA® bias for Red, Green and Blue so they can be returned to these levels when this procedure is complete.

2.Hide all three colors.

3.Increase the ILA® biases to maximum for all 3 colors. With all 3 colors at maximum, the image on the screen should be a white screen with some colors at the edges.

4.Observe the right, left, top, and bottom of the screen. Normally, green is the reference to which blue and red will be matched. (NOTE: If the green ILA® was replaced, the blue or red image should be used as the reference to which green is matched.) If a red or blue border is present on either side or at the top or bottom the ILA® overlap needs adjustment. If both red and blue overlap, the border will be yellow. In either case, proceed with the adjustment below. If there is no overlap, reset the ILA® biases to their previous levels from Step 2.

To perform an ILA® Overlap adjustment:

Remove the rear cover (Section 4.2) and tilt the electronic module up (Sections 3.3).

1.Continue with all three colors hidden.

2.Loosen the 2 wing nuts at the top of the ILA® assembly to be adjusted (Figure 4-12).

3.If the overlap is at the left or right, grasp the ILA® assembly and slide it to the right or left so that the edges coincide with the edges of the other two ILA® assemblies. CAUTION! To avoid

3-10 Model 200 Service Manual