Heathkit H9 - WIDTH

Pase26
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READIUSTMENT
This section
contains
several
adjustments
that
you
may
need to
make to
properly
maintain
your
Video
Terminal. Each of
the adjustments
(except
for Bright-
ness and
Focus) can be adjusted
separately without
affecting other
adjustments.
BRIGHTNESS
Adjust the display brightness
to suit
your
own
needs.
A dim display
is
easier on
your
eyes
when
you
look at
the screen
for
extended
periods
of time. Whenever
you
change the
brightness, it is also a
good
idea to
readjust
the
focus.
The BRIGHTNESS control
(on
the
video
circuit
board) is shown
in Pictorial 3-1.
To adjust the brightness:
1.. Remove the cabinet shell and set it aside.
2. Fill the
screen
with
characters.
3. Adjust the BRIGHTNESS control to
obtain
a
desirable character brightness.
4. Reinstall the
cabinet shell.
FOCUS
The
focus adjustment,
which should be made
whenever
the brightness
is readjusted, assures dis-
tinct characters
on the screen.
The
FOCUS
control
(on
the
video circuit
board) is
shown
in
Pictorial
3-1.
To adjust the focus:
1. Remove the cabinet shell and set it aside.
2. Fill
the screen with characters.
3. Adjust the FOCUS
control to obtain the best
focus. Look
at
the
characters at the
edges
and
corners of the screen as
you
make this
adjustment.
4. Reinstall
the cabinet shell.
CENTERING
The display
should be centered
on the screen. It
should have the
same amount of space on the right
as
it does
on the left, and the
same amount
of space on
the top
as
it
does
on the bottom.
To
adjust the
centering:
1. Remove
the cabinet
shell and
set it
aside.
2. Fill
the
screen with
characters.
NOTE: Use an
insulated screwdriver
and be
careful
you
do not touch
the video circuit board
or
the anode lead
when
you
make the following
adjustments.
3. Refer
to Pictorial
3-1
and
rotate
the center-
ing magnets,
first
one, then the
other, to
center the
display
on the screen. Because
the
centering
magnets
will affect the verti-
cal and horizontal
linearity
of the
display,
use the minimum
amount
of correction
(magnet
tabs
spread as far apart
as
possible)
that is necessary.
Sometimes
you
will have
to
compromise
between
perfect
centering
and
perfect
linearity.
4.
Reinstall
the
cabinet shell.