Panasonic C1381 - Page 18

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,