Service manual
Table Of Contents
ADJUSTMENTS
- PURITY, CONVERGENCE
AND
WHITE
BALANCE
PICTURE
TUBE
The picture tube is a precision in-line gun type. For this
picture tube, dynamic convergence is carried out by a preci-
sion deflection yoke which eliminates the use
of
a con-
vergence yoke and a convergence circuit. The adjustment
of
the picture tube
is
therefore made easier
as
only the ad-
justment
of
static convergence by using a magnet is
enough. The deflection yoke and purity/convergency
magnets assembly
has
been
set at the factory and requires
no field adjustments.
However, should the assembly
be
accidentally jarred or
tampered vyith, some or all adjustment may
be
necessary.
COLOR
PURITY
& VERTICAL CENTER
Loosen yoke retaining clamp
(Fig.
2-1). With a sharp knife,
cut
between the picture tube and the wedge. Remove
wedges completely and clean
off
dried adhesive from the
picture tube. PAINT is used
to
lock the tabs
of
the purity/
convergence magnet assembly in place
(Fig.
2-1). The paint
must
be
removed
with
the end
of
a screwdriver before any
adjustments
are
attempted.
1. Inject a Video Signal (RASTER)
to
the Video input
terminal.
2. Let the purity tabs come
in
line horizontally
as
is
shown
in Fig. 2-3. A long tab should
be
in the same direction
as
the other short tab.
3. Move the yoke slowly backward.
4. Tum the green cut-off control
to
maximum
and
the
red
and blue cut-off controls
to
minimum. Then adjust the
screen control
so
that the green band can
be
seen
best.
(Fig. 2-4)
5 . Rotate the
two
tabs
in
the opposite direction with them
kept at
an
angle. Move them in either direction
so
that
the green band is centered on the picture tube.
6 . Check the vertical center position by displaying a
horizontal line.
If
incorrect, bring it
to
the center by
rotating the
two
tabs, kept at
an
angle, together in
either direction. (Fig. 2-5, 2-6)
7. Repeat steps 5 and 6 alternately until the green band
and the vertical centre are
in
line.
a.
Move the yoke slowly towards the bell
of
the tube so
that
the whole surface of the picture tube is filled
with
a pure green raster.
9. Turning the red
cut-off
control
to
maximum and the
green cut-off control
to
minimum, check for pure
red
raster.
10. Turning the blue
cut-off
control
to
maximum and the
green cut-off control
to
minimum, check
for
pure blue
raster.
11.
Secure yoke retaining clamp (do
not
install wedges at
this time).
YOKE
LOCKING
RING
PURITY
MAGNETS (mark
"P")
Fig. 2-1
(REAR
VIEW)
LONG
AND
SHORT
PROTRUSIONS
Let
the
protrusions come in line
Fig.
2-3
(FRONT VIEW)
_--c..-;?""7f'7':7"T-..L
GREEN
BAND
CENTRE
Bring the green band
to
the
centre.
Fig.
2-4
(FRONT VIEW)
HORIZONTAL LINE
,~.....
f
'
..
/:.....
VERTICAL
CENTRE
(identified
with
a
'---
white
notch)
Bring
the
horizontal line
nearest
to
the
white
notches
shown
in
the
dotted
circles.
, ,
, I
."
Fig.
2-5
(TOP VIEW)
RDG
.
l~J,--
___
--,
Select the
cut-off
service
switch
from
N
to
S. and a
horizontal line
will
appear.
Fig.
2-6
4