Samsung DP14LS Service Manual page 19

5 Alignment and Adjustments
5-3-5 White Balance Fine Adjustment
CONDITIONS
Measurement instrument: Color analyzer
Scanning frequency:
Display image:
X-Y coordinates:
PROCEDURE
1. Adjust the Contrast control so that the
brightness of the video is about 5 ft-L.
2. Check whether the white coordinates of the
video meet the specification above. If they do
not, adjust them so that they do.
3. Adjust the Contrast to maximum luminance.
4. Check whether the white coordinates still
meet the specification above. If they do not,
adjust them so that they do.
5-3-6 ABL Point Adjustment
CONDITIONS
Measurement instrument: Color analyzer
Scanning frequency:
Display image:
Brightness:
Contrast:
PROCEDURE
Adjust ABL so that the brightness level is
35 ± 1 ft-L.
5-3-7 Focus Adjustment
CONDITIONS
Measurement instrument: Color analyzer
Scanning frequency:
Display image:
Brightness:
Contrast:
PROCEDURE
1. Adjust the Focus VR on the FBT to display the
sharpest image possible.
2. Use Locktite to seal the Focus VR in position.
5-3-8 Luminance Uniformity Check
CONDITIONS
Measurement instrument: Color analyzer
Scanning frequency:
Display image:
Brightness:
PROCEDURE
Measure luminance at nine points on the display
screen: top left corner, top center, top right corner,
center row left side, center, center row right side,
bottom left corner, bottom center, and bottom
right corner.
5-6
53.7 kHz/85 Hz
Full white pattern
x = 0.283 ± 0.02
y = 0.298 ± 0.02
53.7 kHz/85 Hz
Full white pattern
Maximum
Maximum
53.7 kHz/85 Hz
ÒHÓ character pattern
Maximum
Maximum
53.7 kHz/85 Hz
White flat field
Cut off point at 30 ft-L
5-3-9 Color Purity Adjustment
Color purity is the absence of undesired color.
Conspicuous mislanding (unexpected color in a
uniform field) within the display area shall not be
visible at a distance of 50 cm from the CRT
surface.
CONDITIONS
Orientation: Monitor facing east
Scanning frequency: 53.7 kHz/85 Hz
Display image: White flat field
Luminance: Cutoff point at the center
of the display area
Caution: Color purity adjustments should only
be attempted by qualified personnel.
PROCEDURE
For trained and experienced service technicians
only.
Use the following procedure to correct minor
color purity problems:
1. Make sure the display is not affected by
external magnetic fields. Use an external
degaussing coil to neutralize magnetic fields
which may be affecting color purity.
2. Very carefully break the glue seal between the
2-pole purity convergence magnets (PCM), the
band and the spacer .
3. Make sure the spacing between the PCM
assembly and the CRT stem is
22.5 mm ± 1 mm.
4. Display a red pattern over the entire display
area.
5. Adjust the Purity Magnet Rings on the PCM
assembly to display a pure green pattern.
(Optimal setting: x = x = 0.283 ± 0.02,
y = 0.298 ± 0.02)
6. Repeat steps 4 and 5 using a red pattern and
then again, using a blue pattern.
Table 5-3. Color Purity Tolerances
Red: x = 0.625 ± 0.015
Green: x = 0.310 ± 0.015
Blue: x = 0.150 ± 0.015
(For 9300K white color adjustment:
x = 0.283 ± 0.02, y = 0.298 ± 0.02)
7. When you have the PCMs properly adjusted,
carefully gule them together with Locktite to
prevent their movement during shipping.
y = 0.340 ± 0.015
y = 0.592 ± 0.015
y = 0.063 ± 0.015
DP14L*/DP15L*