Panasonic C1381 - Page 17

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
Note:
Before
adjusting
convergence,
the
vertical
size,
linearity
and
focus
adjustments
must
be
com-
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,