Beam Form; Lens Focus - Hitachi 53SWX10B Service Manual

2.9 Beam form adjustment
Adjustment preparation
(1) The beam alignment should have been
completed.
(2) The raster
vertical size, scanning area check, and raster
distortion should have been completed.
(3) Set video conditions to factory preset.
(4) Input the dot signal.
Adjustment procedure
(1) Green PRT beam shape adjustment. Short-
circuit 2P (TS) sub-mini connectors on Red and
Blue CPT P.W.B.s to project only the Green
beam.
(2) Turn the green static focus VR, on the Focus
Pack, fully clockwise. (Blooming)
(3) Make the dot at the screen center a true circle
using the 4-pole magnet as shown below.
(4) Also adjust the Red and Blue PRT beam shapes
according to the steps (1) to (3).
(5) After the adjustment has been completed, return
R, G and B static VRs to the just focus point.
PRT SURFACE SIDE
ZERO FIELD
SPACER (NO
ADJUSTMENT)
TRUE CIRCLE SPECIFICATION
b
TRUE CIRCLE DEGREE: a/b
a
2.10 LENS FOCUS ADJUSTMENT
Adjustment preparation
(1) The orientation of PTV set is arbitrary, west,
east, north and south.
(2) Centering DY inclination should have been
adjusted.
(3) Electrical focus adjustment should have been
completed.
(4) Drive VR location adjustment should have been
completed. (Red : 12 O clock, Green : 1~2
O clock).
(5) Receive the cross-hatch pattern signal.
(6) Refer to setup below.
CONTRAST : HALF of full scale.
BRIGHTNESS : minimum
tilt, centering, horizontal/
4-POLE BEAM
SHAPE CORRECTION
MAGNET
2-POLE BEAM
ALIGNMENT
MAGNET
SPECIFICATION: 0.9-1.1
Adjustment procedure
(1) Loosen the fixing screw or wing nut on the lens
cylinder so that the lens cylinder can be turned.
(Be careful not to loosen too much).
completing steps (4), (5), (6) below, tighten the
fixing screws or wing nuts for each lens with a
torque of 1.18N.m (12Kgf cm) ~ 1.67N.m (17Kgf
cm).
(Be careful the lens cylinder does not turn after
having tightened the screw or wing nuts. If it is
tightened too much, lens may tilt or screw may
break.)
Lens Assy
(NOTE 1)
Fixing Screw
TYPE 1
(2) Apply covers to each color of R, G and B lenses.
And project a single color on the screen and
adjust in sequence. (The adjustment order of G,
R and B is only an example.)
(3) If the lens adjustment knob is turned clockwise
viewed from the front, the color Aberration
change as follows.
Cross-Hatch
RED LENS
GREEN LENS
BLUE LENS
(4) In case of G lens. Set to the point where the
chromatic aberration switches from blue to red.
If the chromatic aberration appearing all over
the screen is not the same, observe the vertical
bright line and adjust lens focus as specified in
table below. When the red chromatic aberration
appearing at both sides of the bright line is not
equal, observe the side with larger chromatic
aberration when adjusting.
42
Lens Assy
(NOTE 2)
Fixing Wing Nut
TYPE 2
Color
Aberration
Change of Color Aberration
Short focus Long focus
Orange Scarlet
Blue Red
Purple Green
L1
L2
O
I
After