Samsung PN15VT / VO Service Manual page 16

Display image: Back raster pattern
Full White Pattern
X-Y Coordinates: x = 0.283 ± 0.015,
y = 0.298 ± 0.015
ABL Luminance Refer to 4-3-2(c)
Brightness: Maximum
Contrast: 5 ft-L, 24 ft-L
1. Check whether the color coordinates of the
back raster satisfy the above spec.
If they do not, return to 4-3-2 (a) and readjust
all settings.
2. Display a full white pattern.
3. Select "Geometry" in softjig menu.
4. Select "@7: 5-ft " in right menu.
5. Check whether the white coordinates of the
video meet the above coordinates spec.
6. Select "@8: 24-ft " in right menu.
7. Check whether the white coordinates of the
video satisfies the above spec.
If they do not, return to 4-3-2 (a) and readjust
all settings.
Select "Color" and click "@2: CHANNEL 2"
for color ajdustment for 6500K
Repeat the sequence of 9300K adjustment.
The luminance values the same as 9300K, but
the color coordinated of back raster and white
box are : x = 0.313 ± 0.015 y = 0.329 ± 0.015
4-3-3 Luminance Uniformity Check
Luminance is considered uniform only if the ratio
of lowest to highest brightness areas on the screen
is not less than 7.5:10.
CONDITIONS
Scanning frequency: 54 kHz/85 Hz
(1024 x 768)
Display image: White flat field
Brightness: Cut off point at 24 ft-L
Contrast: Maximum
PROCEDURE
Measure luminance at nine points on the display
screen (see figure below).
Figure 4-10. Luminance Uniformity Check Locations
PN15VT/VO
PN15HT/HO
4-3-4 Focus Adjustment
CONDITIONS
Scanning frequency: 54 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: 54 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)
Table 4-2. 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 ± 0.015, y = 0.298 ± 0.015)
5. 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