Roadstar CTV-1015, Руководство по обслуживанию

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AUTOMATIC DEGAUSSING
A degaussing coil is mounted around the picture tube so that external degaussing after moving
the TV should be unnecessary. But the receiver must be properly degaussed upon installation.
The degaussing coil operates for about 1 second after the power is switched ON. If the set is
moved or turned in a different direction, the power should be OFF for at least 15 minutes.
If the chassis or parts of the cabinet become magnetized, it will result in a poor color purity. If
this happens, use an external degaussing coil. Slowly move the degaussing coil around the
faceplate of the picture tube and the sides and front of the receiver. Slowly withdraw the coil to
a distance of about 6 feet before turning power OFF.
If color shading persists, perform the following Color Purity and Convergence adjustments.
HIGH VOLTAGE CHECK
CAUTION : There is no high voltage adjustment on this chassis. The +B power supply should
be +9 volts (with full color-bar input and normal picture level).
1. Connect an accurate high voltage meter to the second anode of the picture tube.
2. Turn on the receiver. Set bright and contrast controls to the minimum (zero beam current).
3. The high voltage must be measured below 29KV under any conditions.
4. Set sub-Bright DATA(SBR) minimum in FACTORY 1 MODE to ensure that the high voltage
does not exceed the limit under any conditions.
Purity Adjustment
1. Warm up the receiver for at least 30 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. B-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. B-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.
Center Convergence Adjustment
1. Warm up the receiver for at least 30 minutes.
2. Adjust the two tabs of the 4-pole magnets Change the angle between them.
Superimpose the red and blue vertical lines in the center area of the screen.
3. Adjust the BRIGHTNESS and CONTRAST controls for a well-defined picture.
4. Adjust the two tabs of the 4-pole magnets, and change the angle between them.
Superimpose the red and the blue vertical lines in the center area of the screen.
5. Turn both tabs at the same time, keeping the angle constant, and superimpose the red and
blue horizontal lines in the center of the screen.
6. Adjust two-tabs of 6-pole magnets to superimpose the red and blue lines onto the green.
Adjusting the angle affects the vertical lines, and rotating both magnets affects the
horizontal
lines.
7. Repeat adjustments 2-6, if necessary.
8. Since the 4-pole and 6-pole magnets interact, the dot movement is complex(fig B-3).