JVC 250 service manual 8XY Positioner adjust holes

Chapter 4---Optical

Positioner adjusts the light beam coming out of the Light Pipe so that it projects squarely onto the face of the ILA® .

NOTE: Do not adjust the XY Positioner unless there is a dark edge visible on screen.

If the XY Positioner is misaligned, there will be a dark edge on the left, right, top or bottom edge caused by the edge of the Light Pipe. Perform the Arc Lamp alignment before adjusting the XY Positioner unless the dark edge makes Arc Lamp alignment difficult or impossible.

To adjust the XY Positioner:

1.Turn the projector ON and allow it to stabilize for at least 15 minutes.

2.Check the screen for dark edges on the top, bottom, left, or right. Check

the screen with all three colors, using the Variable Flat Field (test pattern #4) or with ILA® bias only. The dark edge will be obvious in either mode.

3.Remove the front cover.

4.There are four access holes; two with small notches on the top of the hole

and two without notches (see Figure 4-8). Use the two access holes without notches. These holes are for full aperture ILA® s. The upper access hole is for vertical adjustment; the lower one is for horizontal adjustment.

5.Insert a 3-mm (long shank) Hex-head wrench into either the horizontal or vertical access hole and adjust the XY Positioner until the dark edge moves off the screen.

Figure 4-8XY Positioner adjust holes.

4-12 Model 250 Service Manual