Samsung AN17HS - Page 8

4-3-6 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:
17 inch : 68 kHz / 85 Hz (1024 x 768)
19 inch : 91 kHz / 85 Hz (1280 x 1024)
Display image: White flat field
Brightness: Cut off point
Contrast: Maximum
PROCEDURE
Measure luminance at nine points on the display
screen (see figure below).
Figure 4-10 Luminance Uniformity Check Locations
4-3-7 Focus Adjustment
CONDITIONS
Scanning frequency: 17 inch : 68 kHz / 85 Hz
19 inch : 91 kHz / 85 Hz
Display image: “Hi” 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.
ANT7HS/ANTZIS/
ANISMS/AN1SIS/AN1SMT
4 Alignment and Adjustments 4 Alignment and Adjustments
4-3-8
Color
Purity
Adjustment
Memo
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 CRY
surface.
CONDITIONS
Orientation: Monitor facing east
Scanning frequency: 17 inch : 68 kHz / 85 Hz
19 inch : 91 kHz / 85 Hz
Display image: White flat field
Luminance: Cut off point at the center
of the display area
Note: Color purity adjustments should onli 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. 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 29 mm + 1 mm.
4. Display a green pattern over the entire display
area.
or
Adjust the purity magnet rings on the PCM
assembly to display a pure green pattern.
(Optimum setting: x = 0.295 + 0.015,
y = 6.594 + 0.015)
6. Repeat steps 4 and 5 using a red pattern and
then again, using a blue pattern.
(Fo: S300K coer achustment: x = C 2u3 e2)
7, When you have the PCMs properly adjusted,
carefully glue them together to prevent their
movement during shipping.
os oo
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ANT?HS/ANITIS/
ANIOMS/ANTSIS/ANTSNT