Hitachi 51SWX20B Training page 113

DP-2X LENS FOCUS ADJUSTMENT
Preparation for adjustment
•
Receive the Cross-hatch
pattern signal.
•
The electrical focus adjust-
ment should have been
completed.
•
Deflection Yoke tilt should
have been adjusted.
•
Brightness = 50%
•
Contrast = 60% to 70%
Adjustment procedure
1) Short the 2 pin sub-
miniature connector on the
CRT P.W.B. TS, to pro-
duce only the color being
adjusted and adjust one at
a time. (The adjustment
order of R, G and B is just
an example.)
2) (See Figure 1) Loosen the
fixing screw on the lens
assembly so that the lens
cylinder can be turned. (Be
careful not to loosen the
screw too much, as this
may cause movement of
the lens cylinder when
tightening.)
3) Rotate the cylinder back
and forth to obtain the best
focus point, while observ-
ing the Cross-Hatch.
(Observe the center of the
screen).
• Hint: Located just below
the screen are the two
wooden panels. Remove
the panels to allow access
to the focus rings on the
Lenses.
FIXING SCREW
Or FIXING WING NUT
LENS ASSEMBLY R, G, B.
Figure 1
4) After completing optical
focus, tighten the fixing
screws for each lens.
5) When adjusting the Green
Optical focus, be very
careful. Green is the most
dominant of the color guns
and any error will be eas-
ily seen.
6) Repeat Electrical Focus if
necessary.
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