9. SUB-BRIGHTNESS ADJUSTMENT
1) Tune in a color program. 2) Set the CONTRAST control to maximum and the BRIGHTNESS control to maximum and the SHARPNESS control to the center position. 3) Set the COLOR and TINT controls to center. 4) Set the SUB-BRIGHT control R554 to center and leave the receiver on five minutes in this state. 5) Watching the picture carefully, adjust the SUB-BRIGHT control in the position where the picture does not show evidence of blooming in high brightness area and not appear too dark in low bright area. 6) Check for BRIGHTNESS controls at both extremes. 7) If the picture does not appear dark with the CONTRAST and BRIGHTNESS control turned to minimum, or not appear bright with the controls turned to maximum, adjust the SUB-BRIGHT control again for an acceptable picture.
10-1. COLOR PURITY ADJUSTMENT
NOTE : Before attempting any purity adjustments, the
receiver should be operated for at least 15 minutes. 1) Demagnetize the picture tube with a degaussing coil. 2) Adjust the CONTRAST and BRIGHTNESS controls to maximum 3) Adjust RED and BLUE Bias controls (R971 and R973) to provide only a green raster. Adjust the GREEN BIAS control (R972) if necessary. 4) Loosen the clamp screw holding the yoke, and slide the yoke backward th provide vertical green belt(zone)in the picture screen. 5) Remove the Rubber Wedges. 6) Rotate and spread the tabs of the purity magnet (See figure 2) around the neck of the picture tube until the green belt is in the center of the screen. At the same time, center the raster vertically. 7) Move the yoke slowly forward until a uniform green screen is obtained. Tighten the clamp screw of the yoke temporarily. 8) Check the purity of the red and blue raster by adjusting the BIAS controls. 9) Obtain a white raster, referring to CRT GRAY SCALE ADJUSTMENT 10) Proceed with covergence adjustment.
10. CONVERGENCE POSITIONING
MAGNET
ASSEMBLY
If Convergence magnet assembly and rubber wedges need mechanical positioning follow figure 2.
