Instruction manual
scan
monitors
and
the
recommended
patterns
associated
PURITY, STATIC CONVERGENCE, DYNAMIC CON-
1<1',,,,,,nt.
are
common
to
Raster Scan
table lists
some
of
the
monitor
adjustments for which
the
patterns
are used.
PATTERNS
Single Crossbar
and Crosshatch (Bold and Fine)
cushion effect, focus
Static convergence
Single Crossbar, Single Dot
4.
convergence
Fine Crosshatch
DEFLECTION'SYSTEM
Many abnormalities in a
monitor
deflection system will show
up
in
a
simple check
of
the
monitor
Always refer
to
the
manufacturer'S
recommendations
when
the
results
of
these tests.
selector
to
the
Fine Crosshatch
pattern.
the
monitor
contrast
and brightness
to
display sharp,
thin
lines
against a black
h",'vnrt"ll
3 Note
the
number
of
vertical and horizontal lines. The
monitor
should
15 vertical and 15 horizontal lines.
The Crosshatch
pattern
a stable display
of
evenly spaced lines
to
make these With this
pattern
displayed, abnormal conditions
such as deflection pin cushion
distortion,
and excessive
60
Hz
hum are easily
detected.
Vertical size and should be
to
produce even spacing
all horizontal lines. It
the
adjustments will
not
permit
this,
then
may
be a vertical deflection
nrrlhL,
..
n
-16-
Pin cushion
distortion
is
most
common
on
screen monitors. The
correct
amount
of
compensation
should make
the
vertical and horizontal
crosshatch lines appear as straight and parallel
as
If
60
Hz
hum
is
entering
the
circuitry,
it
will produce a horizontal bar through
the
pattern
or
apparent
moving waves through
the
pattern.
Generally
the
following
control
type
scan monitors:
Focus
Vertical Size
are present on raster
Vertical Video Position (often a
jumper
on
PC
board)
Focus
Horizontal Hold
Horizontal Video Position
Horizontal Width
Each
of
the
adjustments are intended for small
amounts
correction
on
the
picture. If major corrections are needed involve
the
CRT
Yoke
Assembly.
-17-