Samsung CA17J Series, Service Manual

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4 Alignment and Adjustments
CA17K*/CA17J* 4-7
CONFIDENTIAL
PROCEDURE
Measure luminance at nine points on the display
screen (see figure below).
4-3-4 Focus Adjustment
CONDITIONS
Scanning frequency: 68 kHz/85 Hz
(1024 x 768)
Display image: “H” character pattern
Brightness: Cut off point
Contrast: Maximum
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.
4-3-5 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: 68 kHz/85 Hz
Display image: White flat field
Luminance: Cut off point at the center
of the display area
Note: 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.
2. Make sure the spacing between the PCM
assembly and the CRT stem is 29 mm ± 1 mm.
3. Display a green pattern over the entire display
area.
4. Adjust the purity magnet rings on the PCM
assembly to display a pure green pattern.
(Optimum setting: x = 0.295 ± 0.015,
y = 0.594 ± 0.015)
5. Repeat steps 4 and 5 using a red pattern and
then again, using a blue pattern.
Table 4-4. Color Purity Tolerances
(For 9300K color adjustment: x = 0.283 ± 0.02, y = 0.298 ± 0.02)
6. When you have the PCMs properly adjusted,
carefully glue them together to prevent their
movement during shipping.
Red: x = 0.640 ± 0.015 y = 0.323 ± 0.015
Green: x = 0.295 ± 0.015 y = 0.594 ± 0.015
Blue: x = 0.142 ± 0.015 y = 0.066 ± 0.015
Figure 4-10. Luminance Uniformity Check Locations