JVC Model 200 service manual Arc Lamp Focus adjustments

Chapter 3 Service Adjustments

3.Use the right/left arrow keys on the remote control and adjust the Flat Field to 0%.

4.From the System menu, select Maintenance, then select #3, ILA® Bias. Record the ILA® Bias current value (the Green bias will be readable). This bias value will be returned to when this procedure is complete. The Green value only need be recorded because Red and Blue returns to their original values when Green is reset.

5.Use the right arrow key to increase the ILA® Bias so the Flat Field turns white. If the screen begins to turn from white to a yellow-tinge, use the left arrow and adjust the bias back until an all white flat field is observed. The flat field screen must be white to properly perform the arc lamp focus and alignment.

6.Loosen the large flathead screw (½ turn CCW) at the bottom of the Arc Lamp cover (Figure 4-2), and lift the cover.

7.Defocus the Arc Lamp by turning the Focus Adjust Screw (see Figure 3-1) until a bright, circular area (see Figure 3-2) is achieved. This is the Arc Lamp’s “hot spot.” The sides, top, and bottom areas will taper off in brightness. When performing defocus, do not attempt to narrow the circle too much-try to obtain a uniform circular area.

Figure 3-1.Arc Lamp Focus adjustments.

8.Loosen the 4 X-axis (horizontal) alignment screws (indicated by the letter H inside the screw heads in Figure 3-1).

3-2 Model 200 Service Manual