Samsung PT54925S/SMS, Service Manual

Page: 22 / 104

Alignment and Adjustments
Samsung Electronics 4-11
4-4-5 F.S. (Fail Safe) Circuit Check
Note : The F.S. Circuit check must be performed
after servicing.
1. Turn on the TV.
2. Select the “STANDARD” video mode.
3. Short GT18, GT17 (located on the
Convergence PCB). Then, both sound and
picture disappear. (Note: Even if the shorted
terminals are removed, both sound and
picture do not appear. This proves the F.S.
circuit is working. )
4. To restore both sound and picture, turn off the
TV and reset it after about 30 seconds.
4-4-6 Static Focus Adjustment
PRECAUTION
1. Select the “STANDARD” video mode.
2. Input a crosshatch pattern.
3. Cover the lenses that are not being adjusted.
4. Connect a convergence jig and read data.
5. Adjust the lens for best focus.
(See Fig, 4-1, next page)
STATIC FOCUS (CONTINUED)
Vary the focus pack VR (Red, Blue) on the
front cabinet. Adjust the TV for best possible
focus around the center of the crosshatch
pattern, without losing overall screen balance.
Figure Crosshatch Pattern
Examine these points together.
4-4-7 Lens Focus Adjustment
PRECAUTIONS
1. Do this adjustment after the static focus
adjustment and the tilt adjustment.
2. Select the “STANDARD” video mode.
(Contrast:64, Brightness:32)
3. Input a crosshatch pattern.
ADJUSTMENT
1. Loosen the lens screws.
2. Cover the two lenses that are not being
adjusted.
3. Adjust the lens, observing the color aberration
vertically and horizontally within 3 blocks of
the center of the crosshatch pattern.
4. When the lens is turned clockwise, the color
aberration will change as follows:
Lens Color Aberration Change
R Orange - Crimson
G Blue - Red
B Purple - Green
5. Green lens adjustment:
Set the lens at the point where Blue just
changes to Red. If the color aberration is
irregular throughout the picture screen, adjust
the lens to show Red color aberration
(approximately 1~3 mm area) within a 3-block
grid around the horizontal center-line. If the
color aberration is irregular, adjust the lens as
shown in the diagram below. (Accurate
alignment of Green is important for overall
color quality.)
6. Red lens adjustment
Set the Red lens at the point where Orange
becomes Crimson.
7. Blue lens adjustment
Set the Blue lens at the point where Purple
becomes Green.
P
L1 L2
RED ABERRATION BLUE ABERRATION
L1, L2 < P
_
Fig. 4-1 Crosshatch Pattern.
Fig. 4-2 Color Aberration
Examine these points together