JVC 250 service manual

Chapter 5---Electronics

10.Recheck all Geometry and Convergence settings and readjust wherever necessary.

11.Replace the rear cover.

Front/Rear Projection Jumper Settings

In the procedures below each of the jumpers mentioned have a specific purpose: J100 and J101 are the horizontal scanning jumpers, J 53 and J53A are the vertical scanning jumpers, and J50 and J50A are the convergence jumpers.

CAUTION! Do not attempt to switch jumpers while the projector is operating. The projector must be powered OFF when Scan Reversal Jumpers are being changed.

Front/Rear Jumper Setting (Horizontal Reverse)

!The Horizontal Scan Reversal Jumper reverses the image projection for front or rear projection. Figure 5-25illustrates the jumpers’ location on the Scan Reversal Board.

!The Model 250 Projector is shipped with the jumper plugs inserted in J50 and J100 for front/upright projection (see Table 5-1for other orientations).

To set the Horizontal Scan Jumper:

1.Power off the projector by IR Remote or PC, and allow the cooling fans to run until they shut off automatically).

2.Turn the AC Circuit Breaker to the OFF position and unplug the AC Power Cord.

3.Remove the rear cover.

4.Verify that the Horizontal Scan Reversal jumper is plugged into J100 and the convergence jumper is plugged into J50 for front projection (see Figure 5-25and Table 5-1).

5.Switch the Horizontal Scan Reversal jumper to J101 and the Convergence Jumper to JA50 for rear projection (see Figure 5-25and Table 5-1).

6.Replace the projector cover.

7.Power ON the projector and allow it to stabilize for a minimum of 15 minutes. It is recommended that the projector be operating for a least one hour before performing shading adjustments.

8.Recheck centering, convergence, and shading when changing jumpers for front or rear screen projection.

Model 250 Service Manual 5-41