Samsung CS30A7HPTX/BWT Service Manual page 17

Alignment and Adjustments
5-4 RF AGC Adjustment
1. Turn to the strongest local station.
2. Turn the AGC control fully clockwise (VR101, on the MAIN board).
3. Adjust the AGC control until noise(snow)disappears from the screen.
5-5 FOCUS Adjustment
1. Input a black and white signal.
2. Adjust the tuning control for clearest picture.
3. Adjust the FOCUS control for well defined scanning lines in the center area of the screen.
5-6 SCREEN Adjustment
1. Turn to the ACTIVE channel.
2. Adjust the VR screen for a normal picture is (no blooming or flyback line).
3. Adjust the SCREEN control for well defined scanning lines in the center area of the screen.
5-7 Purity Adjustment
1. Warm up the receiver for at least 20 minutes.
2. Plug in the CRT deflection yoke. Tighten the clamp screw.
3. Plug the convergence yoke into the CRT and set it as shown in Fig. 5-1.
4. Input a black and white signal.
5. Fully demagnetize the receiver by using an external degaussing coil.
6. Turn the CONTRAST and BRIGHTNESS controls to maximum.
7. Loosen the clamp screw holding the yoke.
Slide the yoke backward or forward to produce a vertical green belt. (Fig. 5-2)
8. Tighten the convergence yoke.
9. Slowly move the deflection yoke forward.
Adjust for the best overall green screen.
10. Temporarily tighten the deflection yoke.
11. Produce blue and red rasters by adjusting the -low-light controls. Check for good purity in each field.
12. Tighten the deflection yoke.
5-2 Samsung Electronics