JVC Model 200 service manual CRT Mechanical Focus

Chapter 3---Service Adjustments

either one of these adjustments while the set screws are loose may cause the CRT to go out of focus or rotate.

3.5CRT Mechanical Focus

The CRT Mechanical focus is factory-set and will not normally require adjustment. When a CRT is replaced, the CRT mechanical focus must be reset. Adjust colors individually. After completing, recheck other colors for additional adjustment. Replacing the CRT could cause other colors to become misadjusted. Use the Focus test pattern (an external signal or other test patterns can also be used) for adjustment.

To adjust the CRT Mechanical Focus:

1.Remove the rear cover (Section 4.2)

2.Tilt the Electronic Module to the upright position (Section 3.3).

3.Select the Focus test pattern.

3.Zoom the Projection Lens to the widest angle (largest image) and adjust the Projection Lens focus for the sharpest image of the Focus test pattern.

4.Tilt the Electronic Module up (Section 3.3).

5.Loosen the two set screws (Figure 3-5) near the top of the CRT sleeve.

6.Loosen the CRT focus lock screw located on the Guide Plate at the top of the CRT shield (Figure 3-5). The CRT is now free to slide.

7.Grasp the CRT thumbscrew (Figure 3-5) and slide the CRT back and forth until the image is focused as sharply as possible (be careful not to loosen the CRT thumbscrew which could cause the CRT to rotate).

8.Tighten the set screws first, then the CRT focus lock screw. NOTE: Tighten set screws before focus lock screw. The focus lock screw can slightly defocus or rotate the CRT as it is being tightened if the set screws are loose.

9.Repeat the above steps for the Red and Blue CRTs.

Model 200 Service Manual 3-7