JVC 330, 370 SC, 340 SC service manual Electronic Focus

Chapter 3---Service Adjustments

9.Cutoff R and view B.

10.Repeat Steps 2-4 for Blue.

3.8 Electronic Focus

The Electronic Focus adjustment is factory-set and should not need to be adjusted. Whenever a major component has been replaced, like a CRT, or if the high voltage power supply has been repaired the electronic focus will have to be readjusted. To do this, select Test Pattern 8, H-GRID, and observe the screen for a sharp focus at the center of the screen.

If the center appears sharply focused, there is no need to perform the electronic focus. Follow the procedure below if readjustment is necessary.

NOTE: The electronic focus adjustment focuses the electron beam in the CRT. View one color at a time for these adjustments. Recheck the focus of each color because some interaction between R, G and B may occur. The electronic focus adjustment panel is located on the High Voltage Power Supply on the left-rear side of the projector (refer to Figure 3-5).

To adjust the electronic focus:

1.Press TEST 1, Test Pattern 8, H-GRID.

2.Cutoff R and B.

3.Continue with a low resolution source (31.5kHz/60Hz) connected to the projector inputs and Size is at 100% from the previous CRT Mechanical Focus procedure.

4.Using a small plastic screwdriver, adjust the electronic focus for Green and observe the center of the screen. Have another person watch the center of the screen up close while adjusting.

NOTE: Be careful to adjust the ELECTRONIC FOCUS and not G2. These adjustments are close to each other and one could be mistaken for the other. (Figure 3-5).

5.Cutoff G and view R.

6.Repeat Step 3 for R electronic focus.

7.Cutoff R and view B.

8.Repeat Step 3 for B electronic focus.

3-12 Model 330, 340SC, 370SC Service Manual