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4. Sub Contrast Adjustment
(See A-3 of Page 31)
a) Apply 220V AC to the unit.
b) Apply a VGA
signal with white pattern to the unit.
c) Fully turn screen control
of FBT counterclockwise.
d) Turn
R3116
(BRIGHT)
and
R3115
(CONTRAST)
controls fully clockwise.
e) Connect
a oscilloscope
between
TP47G
and ground.
f) Adjust
R3124 (SUB.CONT.)
to set the oscilloscope
42V + 1.0Vp-p.
. Video Bias Adjustment
(See D-1 of Page 31)
a) Apply 220V AC to the unit.
b) Apply a VGA
signal with black pattern to the unit.
c) Turn
R3116
(BRIGHT)
and
R3115
(CONTRAST)
controls fully clockwise.
d) Turn R3511
(G. CUT OFF) to center position.
e) Connect
a digital
voltmeter
between
TP47G
and
ground.
f) Adjust
R3580
(VIDEO
BIAS) to set the voltmeter
at 70V.
. White Balance Adjustment
(See D-1, C-3, E-1, E-2 of Page 31)
a) After adjusting VIDEO
BIAS, adjust Bright control
(R3116) to set the voltmeter 75V + 1V.
b) Connect GND and TP401 with short wire.
c) Slowly turn the screen control clockwise until a dim
green
horizontal
line appears
on
the picture
tube.
d} Make
the horizontal
line white
by turning
R3510
(R-CUT OFF) and R3512 (B-CUT OFF).
e) Remove the short wire connected at step (b).
f) Apply a full white field signal to the unit.
g) Turn
Bright control
(R3116)
and
Contrast control
(R3115) fully clockwise.
h) Adjust
R3501
(R-DRIVE)
and R3503
(B-DRIVE)
to produce a normal white pattern.
i) Check
that
the uniform
white
pattern
is achieved
from low brightness to high brightness levels.
Proper
tracking at all brightness levels can be obtained when
the screen control, cutoff controls and drive controls
are properly adjusted. If the results are unsatisfactory,
repeat all the above steps.
X = 0.284 (+ 0.01 at 25 ft-L, + 0.01 at 3 ft-L)
Y = 0.294 (+ 0.01 at 25 ft-L, + 0.01 at 3 ft-L)
25ft-L = 85.6 nit (cd/m?)
3ft-L = 10.3 nit (cd/m?)
7.
eta ee
Convergence Adjustment a
pleted.
a) Apply
a VGA
signal with crosshatch
pattern
to the
unit,
b) The
brightness
level
should
be
no
higher
than
necessary to obtain a clear pattern.
c) Loosen
the convergence
magnet
lock ring and con-
verge the red and blue lines at the center of the screen,
by rotating the R-B Static Convergence Magnet.
(See figure 28)
d) Align
the
converged
red/biue
lines with
the green
lines
at the
center
of the
screen
by rotating
the
(See figure 28)
Tighten the convergence magnet lock ring.
(RB)-G
Static Convergence
Magnet.
e
f) Remove
the DY wedges
(see figure 29) and slightly
tilt (do not rotate) the deflection yoke horizontally
and vertically to obtain good overall convergence.
g) Secure the deflection yoke by reinserting the wedges.
(See figure 29).
h) If purity error is found, repeat the purity adjustments.
R-B Static Convergence
Magnet
Lock Ring
(Turn counterclockwise
to unlock Convergence
& Purity Magnet.)
& Purity Magnet
Purity Magnet
Figure 28
Magnet
Figure 29
(RB)-G Static Convergence
Clamp for Convergence
f,
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