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8. Color Purity Adjustment *K
{See figure 28 and 30) |
a) Operate the display
for 20 minutes, with the Bright |
control at max position to warm up the CRT.
b} Degauss
the display
fully by using an external
de-
gaussing coil.
c) Roughly adjust convergence.
d) Apply
a VGA
signal with white pattern to the unit.
e) Turn
red and
blue
Cut
Off controls fully counter-
clockwise to obtain a green field.
Adjust Drive controls if green field is not obtained.
f) Loosen
the deflection
yoke clamp
screw and move
the deflection
yoke as close to the purity magnet as
possible.
g)
Loosen
the purity magnet
lock ring
(see figure 28)
and adjust the purity magnet to set the vertical green
raster
precisely
at the center
of the screen.
(See
figure 30)
Then tighten the lock ring.
h) Slowly move the deflection yoke forward and adjust
for the best overall green screen.
i) Tighten the deflection yoke clamp screw.
j) Produce the blue and red raster by Cut Off controls
and
observe
that
good
purity
is obtained
on
the
respective field.
k) Observe that a uniform white raster is obtained by
adjusting
R, B Cut Off controls.
!f screen
is not
uniformly white, repeat above procedure,
Note:
Purity
correction
magnet
may
be effective to
control purity slightly.
"7,
Convergence
Adjustment'
and
'8. Color
Purity
Adjustment'"'
are
not
necessary
when
the
CRT
is
replaced as ITC.
ML
Green Raster
Figure 30
Figure 31
Horizontal
Line
—
18 —
9. Raster Brightness Adjustment
(See A-2 and B-2 of Page 31}
a) Apply a VGA signal with full black pattern.
b) Turn
R3116
(BRIGHT)
and
R3115
(CONTRAST)
controls fully clockwise.
c) Adjust the screen control
of FBT so that the Back
Raster
is no
longer
visible
when
viewed
from
a
distance of 30 cm.
10. Brightness Adjustment
(See A-3 of Page 31)
a) Apply a VGA signal with full white pattern.
b) Turn R3116
(BRIGHT)
and R3115 (CONTRAST)
controls fully clockwise.
c) Adjust R3126 (SUB BRIGHT) to 31 ft-L brightness.
31ft-L = 106.2 nit (cd/m?)
CAUTION:
Too high R3126
(SUB BRIGHT) setting
can result in lower CRT life.
11. Focus Adjustment
a) Apply a VGA signal with crosshatch pattern.
b) Focus
red, green,
blue and
white
pictures to the
sharpest on the whole screen with focus control of
FBT.
12. Pincushion Adjustment
(See D-4 of Page 31)
a) Apply a VGA
signal with crosshatch
pattern to the
unit.
b} Adjust
R456
(PINCUSHION)
to
set
pincushion
error is within + 0.02 in. (0.05 mm).
13. V-Linearity Adjustment
(See C-2 of Page 31)
a) Apply a VGA
signal with crosshatch pattern to the
unit.
b) Adjust
R416
(V. LIN.)
to equal the length of A
and B.
Figure 32
f,
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