VISUAL
TECHNOLOGY
INCORPORATED,
540
MAIN
STREET,
TEWKSBURY,
MA
01876
7.5
TV
MONITOR
PCB
REMOVAL
AND
INSTALLATION
In order
for
the
TV
monitor
PCB
to
be
removed
it
is
necessary
to
remove the rear panel and
top
cover,
or
remove the rear panel and the logic
PCB.
Disconnect the cable connecting the
logic
PCB
and the
TV
PCB
at the
TV
end. Disconnect the yellow and black connector and
the blue and
red
connector connecting the
TV
PCB
to
the yoke from the
TV
PCB,
and the
flyback transformer cable
from
the
TV
PCB.
Unplug the connector assembly
from
the end
of
the picture tube. Squeeze and disconnect the black wire at the
top
corner
of
the picture
tube. Slightly
tip
the
unit
and
squeeze
and
press
four
plastic standoffs extending through
the
base
plate. Lower the
unit
onto
its feet and remove the
TV
PCB.
Remove the
four
plastic standoffs from the
PCB
by
squeezing the locking tab and remove. Reinstall these
four
standoffs
into
the
base
plate.
Installing the
TV
PCB
is
accomplished by pressing the
PCB
into
place
·on
the
four
plastic
standoffs, pressing the board
unti.1
the locking tabs
snap
into place.
Plug
the CRT socket
onto
the CRT. Plug the flyback connector
onto
the board. Plug the yellow and black yoke
connector onto the board adjacent
to
the
two
wire wound coils.
Plug
in the blue and
red
yoke connector
into
the other socket, and plug in the
PCB
edge
connector. Connect the
black wire from the CRT socket assembly onto the ground finger tab at the
top
front
corner
of
the CRT.
CAUTION
When installing the yoke and flyback connectors observe orienta-
tion.
Each
of
these connectors
can
be
installed backwards.
When
they
are
installed back-
wards considerably more force
is
required.
7.6 CRT
AND
FLYBACK
REMOVAL
AND
INSTALLATION
Before removing the picture tube
it
is
necessary
to
discharge the tube. With
an
insulated
handled screwdriver short
out
the high voltage
lead
to
the tube. Carefully
lift
the
top
edge
of
the high voltage connector and insert the end
of
the screwdriver.
Cause
the screwdriver
shaft
to
touch the sheet metal bracket and the contact
of
the high voltage connector simul-
taneously. The high voltage connector
can
now
be
removed by rocking
it
while pulling
it
up. Disconnect the yoke, ground wire, and the tube socket assembly
as
described in
section 7 .5. While holding the lower
front
edge
of
the picture tube in one hand, remove the
four
mounting screws, and remove the picture tube. The picture tube neck should
not
be
subjected
to
any pressure
or
shock. Store the picture tube on its
face.
The flyback trans-
former
can
now
be
removed
by
unplugging
it
from
the
TV
PCB
and removing
two
mounting
screws.
When
installing the picture tube install the lower
two
screws first. Insert the ground
finger between the mounting bracket and the
top
picture tube mounting tab. Install the
top
two
screws and connect the
cables.
Be
sure
that
the black ground wire
is
installed!
7.7
TV
MONITOR
ADJUSTMENTS
Refer
to
Figure 7-3
for
the location
of
the adjustments.
Enter SET-UP B and set
light
background
screen
(see
Sec.
3-2).
Set
full
intensity
by
pressing and holding the t key
until
the intensity no longer increases.
Brightness Control:
Adjust
it
so
that
the raster lines
are
visable.
Horizontal
Phasing
Control:
Adjust
the phasing control
so
that
the video
area
is
centered
horizontally
within
the raster
area.
Brightness Control: Reduce the brightness
until
the raster just disappears.
57
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