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PROCEDURE
Measure luminance at nine points on the display
screen (see figure below).
Figure 4-10. Luminance Uniformity Check Locations
4-3-4 Focus Adjustment
CONDITIONS
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.
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:
Scanning frequency:
Display image:
Luminance:
Note: Color purity adjustments should only be
attempted by qualified personnel.
AP17K*/AP17J*
68 kHz/85 Hz
(1024 x 768)
"H" character pattern
Cut off point
Maximum
Monitor facing east
68 kHz/85 Hz
White flat field
Cut off point at the center
of the display area
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
Red:
x = 0.640 ± 0.015
Green:
x = 0.295 ± 0.015
Blue:
x = 0.142 ± 0.015
(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.
4 Alignment and Adjustments
y = 0.323 ± 0.015
y = 0.594 ± 0.015
y = 0.066 ± 0.015
4-7
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