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Serviceman Mode (Electronic Controls, Cont.)
CRT DC Bias
White Balance Adjustment
1. Use the one line convergence pattern from the
This adjustment requires that the serviceman use skills
NTSC generator.
in observing what a screen without color should look
6
2. Check the green and red cathode voltages at
like.
TPLGl & TPLR1 for 200 volts from ground to black
Enter the
3. Check the blue cathode voltage at TPLB1 for 210
2.
a monoscope pattern to
One
the
volts from ground to black.
inputs.
DC BIAS
TPLGl
TPLRl
TPLBl
200Vk 2V (R,G)
21 0Vk 2V for Blue Cutoff
GND
High Light White Balance Adjustment
1. Adjust DAC C3 for Red and C4 for Blue
adjustments.
2.
Make sure the screen is not blue or red. The
screen should be white in all areas.
3. Check the monoscope pattern for a black and
white picture with even shades of gray and no color
tint in the picture.
Red, Green & Blue Screen Cutoff
Low Light White Balance Adjustment
@
1. Use either a no input signal condition or raster from
1. Adjust DAC CO for red and DAC C2 for blue.
the NTSC generator.
2. Check the screen for even white in all areas, no
2. Observing the green tube directly or via a reflective
color.
surface, adjust the VR on the green tube for
3.
Check the monoscope pattern
a black and
minimum noise.
white picture, even shades of gray and no color tint
3. Adjust the noise level in the red and blue tubes to
in the low light areas.
match the noise level in the green tube.
4.
Repeat the High Light and Low Light White
Balance again until the white balance tracks from
-
1
S1 =
PIP contrast
I
I
1
0-127
1
37
I
I
S3
=
Lower (119)
1
0-255
1
149
k=
Left (119)
S5 =
Right (119)
S6 = Umer (1116)
b 9
= Right (1116)
I
I
(
0-255
1
124
I
SA = (Not Applicable)
I
-
I
-
I
0-255
0-255
-
0-255
I
I
SB
=
Clock adjust
1
0-255
1
161
7
107
1
7
0
,
,
S7 = Lower (111 6)
S8
=
Left (1 11 6)
I
I
SC = PIP tint
1
0-63
1
50
high light to low light.
0-255
0-255
Tint and Color Check
Again, the serviceman ability to see color and the
balance of color is important for theses adjustments.
165
7
Tint Check
1. In Picture Menu set Picture Norm to YES.
2. Apply color bars to the video input.
3. Magenta is composed of two colors, blue and red.
4.
Check to see that magenta does not have too
much blue or too much red.
5. Check Cyan. Cyan is composed of blue and green.
It should not have too much blue or green.
6. Use a test signal from a VCR or laser disk that has
a pre-recorded close up of a signal that has good
flesh tones.
7. The signal on the VCR or laser disk should look
normal.
Color Check
Using a clean RF or video signal, set the color level so
that it does not saturate or appear harsh. Make sure
that color is not set so that it appears dull and washed
out. Look for natural colors, try to adjust the picture to
appear as a normal photograph.
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