Alignment and Adjustments
4-3-3 High Voltage Check4-3-6 Purity Adjustment
CAUTION: There is no high voltage adjustment on this chassis.1. Warm up the receiver for at least 20 minutes.
The B+ power supply must be set to +125 volts (Full color bar input
and normal picture level).2. Plug in the CRT deflection yoke and tighten
the clamp screw.
1. Connect a digital voltmeter to the second
anode of the picture tube.3. Plug the convergence yoke into the CRT and
set in as shown in Fig. 4-2.
2. Turn on the TV. Set the Brightness and
Contrast controls to minimum (zero beam cur-4. Input a black and white signal.
rent).
5. Fully demagnetize the receive by applying an
3. The high voltage should not exceed 27.5KV.external degaussing coil.
4. Adjust the Brightness and contrast controls to6. Turn the CONTRAST and BRIGHTNESS con-
both extremes. Ensure that the high voltagetrols to maximum.
does not exceed 27.5KV under any conditions.
7. Loosen the clamp screw holding the yoke.
4-3-4 FOCUS AdjustmentSlide the yoke backward or forward to pro-
vide vertical green belt. (Fig. 4-3).
1. Input a black and white signal.
8. Tighten the convergence yoke.
2. Adjust the tuning control for the clearest pic-
ture.9. Slowly move the deflection yoke forward,
and adjust for the best overall green screen.
3. Adjust the FOCUS control for well defined
scanning lines in the center area of the screen.10. Temporarily tighten the deflection yoke.
11. Produce blue and red rasters by adjusting the
4-3-5 Cathode Voltage Adjustment
low-light controls. Check for good purity in
(Screen Adjustment)
each field.
1. Connect CRT socket pin GK to an oscilloscope
12. Tighten the deflection yoke.
probe.
2. Input a gray scale pattern. (Use a pattern gen-
erator, PM5518)
3. Use the P mode key (on the remote control)
for the STANDARD picture.
4. Adjust the Screen VR (on the FBT) so that the
voltage on the oscilloscope becomes 130+2.5V_
(See Fig. 4-1).
130 2.5V+_
GND
14, 16" :120 2.5V+_
20, 21" : 130 2.5V+_
Fig. 4-1
4-16Samsung Electronics |
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