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Alignment and Adjustments
Alignment and Adjustments
4-3-3 High Voltage Check
CAUTION: There is no high voltage adjustment on this chassis. The B+ power supply must be set to +155 volts (Full color bar input and normal picture level).
4-3-6 Purity Adjustment
1. Warm up the receiver for at least 20 minutes. 2. Plug in the CRT deflection yoke and tighten the clamp screw. 3. Plug the convergence yoke into the CRT and set in as shown in Fig. 4-2. 4. Input a black and white signal. 5. Fully demagnetize the receiver by applying 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 provide vertical green belt. (Fig. 4-3). 8. Tighten the convergence yoke. 9. Slowly move the deflection yoke forward, and 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.
1. Connect a digital voltmeter to the second anode of the picture tube. 2. Turn on the TV. Set the Brightness and Contrast controls to minimum (zero beam current). 3. The high voltage should not exceed 33KV. 4. Adjust the Brightness and contrast controls to both extremes. Ensure that the high voltage does not exceed 33KV under any conditions.
4-3-4 FOCUS Adjustment
1. Input a black and white signal. 2. Adjust the tuning control for the clearest picture. 3. Adjust the FOCUS control for well defined scanning lines in the center area of the screen.
4-3-5 Screen Adjustment
1. Connect CRT socket pin GK, BK, RK to an oscilloscope probe. 2. Input a gray scale pattern. (Use a pattern generator, PM5518) 3. Use the Picture mode for the STANDARD picture. 4. Adjust the Screen VR (on the FBT) so that the voltage on the oscilloscope becomes 140+2.5V _ (See Fig. 4-1).
