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SERVICE INFORMATION
ADJUSTMENTS
signal adjustment (Described in steps 1-4 above) have
WY BRIGHTNESS
been completed.
or other black and white information
moreover,
the video
polarity is usually white characters on a black background.
The brightness control should be adjusted at a point where
the while raster is just extinguished the CRT with then be
at its cut off point, and a maximum
contrast ratio can be
obtained when a video signa! is applied fully.
V VERTICAL ADJUSTMENTS
There is a slight interaction among the vertical frequency
height and linearity controls. A change in the height of the
picture may affect linearity.
|) Set
the
vertical-hold
control
VR302,
near
the
mechanical
center of its rotation.
2) Adjust the vertical
linearity control
VR30!
for best
vertical linearity.
3) Adjust the vertical height control VR303 for desired
height.
4) Readjust
the
vertical
hold
control
VR302
until
the
picture "locks" on vertical sync.
5) Recheck height and linearity, and readjust, if necessary.
6) Slight readjustment of vertical hold contol, VR302 may
be required if the picture "Rolls" up or down after a
power off/on sequence.
HORIZONTAL ADJUSTMENTS
Raster width is affected by a combination of the DC power
supply,
horizontal
width coil and the horizontal
linearity
coil.
|) Horizontal Linearity
When character width variation is observed in characters
of one row, turn the core of adjustor
so that
character
width should become uniform.
2) Horizontal Width
Adjust horizontal width by turning the core of with a
plastic hexdrive for the desired width.
3) Readjust horizontal linearity and width coil for proper
width.
4) Observe final horizontal linearity and width, and touch
up either adjustment
if needed
the raster should be
properly locked and centered when the horizontal drive
|) Raster Centering
if the
raster
is not
properly
centered,
it may
be
repositioned by rotating the ring magnets
behind the
deflection yoke.
The
ring magnets
should
not be used
to offset the
raster from its nominal center position because it would
degrade the resolution of the display if the picture is
tilted, rotate the entire yoke.
i
2) Geometric Corrections
The magnets on the yoke assembly shall be polarized so
as to provide adjustment of pin-cushion, barreling and
other
geometric
deformitics
by simply
rotating
the
magnets until the desired display is achieved readjust if
necessary.
FOCUS ADJUSTMENTS
Although the focus control, VR502 dose not have a large
effect
on
focus
because
of
the
CRT
gun-assembly
construction.
So there is a dynamic focus which does not control.
If provides
some
adjustment
for
maintaining
the
best
overall display focus.
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