JVC 370 SC, 330, 340 SC service manual Horizontal Size Tracking

Chapter 3---Service Adjustments

3.5 Horizontal Size Tracking

The horizontal width coils are factory adjusted and will not normally need adjustment. In general, if the R and B vertical lines are within two (2) crosshatch lines of each other, they can be brought in line with the Convergence procedure. If the R or B horizontal size does not match G within two crosshatch lines, adjust the Horizontal Width coils on the R and B Deflection Yokes (refer to Figure 3-1). The width coils are mounted on a small circuit board on top of the Yoke assembly inside a white ceramic holder and the adjustment is accessed from the opening at the end of the ceramic holder.

WARNING!!! To prevent possible electrical shock when performing the width coil adjustment always wear ANSI/ASTM 10,000 volt rated safety gloves for protection from the high yoke voltages that are present. Make sure the gloves are not cracked.

To adjust the horizontal size tracking:

1.Remove the rear cover and electronic module cover by removing the 2.5mm Allen screw holding the electronics module in place and tilting the electronics module (see CAUTION! below) back to gain access to the yoke.

CAUTION! Remove anything plugged into the rear electronics jacks or the plugs could be badly damaged when the electronics module is tilted back.

2.View G and R.

3.Using the POS and arrow keys, position Red over Green so that each edge of the pattern has the same amount of error. Adjust the Red coil until the edges align.

4.Use a small plastic hex screwdriver to turn the red coil core (the red CRT is on the right side looking from the rear) clockwise or counterclockwise until the Red horizontal size matches Green.

5.Cutoff R and view G and B.

5.Use a small plastic hex screwdriver to turn the blue coil core (the blue CRT is

on the left side looking from the rear) clockwise or counterclockwise until the Blue horizontal size matches Green.

6.Tilt the electronics module back into place.

7.Replace the allen screw from Step 1 above.

Model 330, 340SC, 370SC Service Manual 3-7