Table of Contents
Advertisement
Service Adjustments
L
?
.
L
L
.
.
L
SAFETY PRECAUTIONS
:
An isolation transformer
should be connected
in the power line between
the receiver
and the AC
line before
any service
is performed
on the receiver.
X-RADIATION
PRECAUTION
The primary
source
of X-RADIATION
in television
receiver
is the picture tube, The
picture
tube is specially
constructed
to limit X-RADIATION
emission.
For continued
X-RADIATION
protection,
the replacement
tube must
be the same
type as the original
including
suffix letter, Excessive
high voltage
may
produce
potentially
hazardous
X-RADIATION.
To avoid
such hazards,
the high voltage
must be maintain
within specified
limit.
Refer
to this service
manual
for specific
high
voltage
limits. If high voltage
exceeds
specified
limits, take necessary
corrective
action. Carefully
follow the instructions
for + B1 volt
power supply adjustment,
and high voltage
check to maintain
the high voltage
within the specified
limits.
NOTE;
Do not attempt
this adjustment
with weak signal.
(1) Tune
the
receiver
to most
clearest
(or strongest)
VHF
station
in
your
area.
Set
the
brightness
and
contrast
controls
to maximum.
Set the colour
control
to minimum.
(2) Set AGC(VR191
) control
to mid-
range.
(3) Turn
AGC
control
in direction
which
causes
snow
to appear,
then
in the opposite
direction
until the snow
just disappears.
(1) Connect
DC meter to R638
(R637
side) and the ground.
Set the +B - adjustment
control (VR631 ) to mid- range.
(2) Set the brightness
and contrast
to minimum.
Tune
the receiver
to an active
channel
and synchronized
picture.
(3) Adjust
+B - adjustment
control(VR631
) for 130
* 0.5 volt
DC.
(1) Receive
the monochrome
circular pattern.
(2) Set the brightness
and contrast
to normal.
(3) Adjust VR351
for optimum
horizontal
center position.
.
Horizontal
center
11
(1) Receive
the monochrome
circular pattern.
(2) Set the brightness
and contrast
to normal.
(3) Vertical
centering
can be adjusted
by switching
SW501.
Vertical
center
+!
(1) Receive
the monochrome
circular pattern.
(2) Set the brightness
and contrast
to normal.
(3) Vertical
size can be adjusted
by using VR51 O
rtical size
(1) Receive
the monochrome
circular pattern.
(2) Set the brightness
to normal and contrast
to maximum.
(3) Adjust the focus control on the F,B.T
for the best focus on
the screen
center.
(1) Receive
the monochrome
circular pattern.
(2) Set the brightness,
contrast
and colour to normal.
(3) Set the service
switch (SW191
) at the service
side.
(4) Set
the
drive
volume
(VR702
and
VR712)
at
their
mechanical
center.
(5) Set
the
bias
volume
(VR701,
VR721
and
VR711 ) to
minimum
(fully counter
clockwise).
(6) Turn the screen
volume
on the FBT to obtain
just visible
one coloured
line.
(7) Adjust each bias volume
(VR701
- blue, VR721
- green
and
VR711
- red) alternately
until a dim white line produced.
(8) Set the service
switch (SW191
) at the normal
side.
(9) Adjust
the drive
volume
(VR702
- blue and VR712
- red)
alternately
to produce
normal
black and white picture.
(1 O)Check
for proper
grey
scale
tracking
at all brightness
levels.
NOTE:
If the grey scale adjustment
is made
after picturetube
replacement,
check the high voltage.
(1) Receive
the monochrom
circular pattern.
(2) Set the brightness
and contrast
to maximum.
(3) If the picture is too wide or narrow, cut or short the "JP436
on the main unit, When
JP436
is shorted,
the horiz. width
increase.
When JP436
is cut, the horiz. width decrease.
Important
Note:
If JP436
is cut, its gap
must
be more
than 5mm to prevent
sparks.
"=&0rethan5mm
(4) Connect
a high voltage
probe to anode
lead
of the picture
tube.
(5) The high voltage
must be between
20-22KV(14"),
24- 26KV
(20", 21 ").
NOTE:
If the picture tube is replaced,
check the high voltage.
Note: It is not necessary for this modei to make
the ViF Adjustment.
<
J
–5–
Advertisement
Table of Contents
