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 XRADIATION. To avoid such hazards, the high voltage must be maintain within specified limit. Refere 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.
SUB BRIGHTNESS ADJUSTMENT
1.
Connect a DC meter between “TP - H“ (positive lead) and
“TP - G“ (negative lead) on main unit.
2. Receive the monochrom circular pattern.
3. Set the brightness to maximum and the contrast to
minimum.
4. Adjust the sub brightness control (VR211 ) for 0.4 volt.
NOTE: If the picture tube replaced, check the sub- brightness
adjustment.
HORIZONTAL CENTER ADJUSTMENT
1.
Tune the receiver to the monochrome circular pattern.
2. Set the brightness and the contrast to maximum.
3. Adjust video phase(VR411 ) for optimum horizontal center
position.
TUNING DISPLAY CENTER ADJUSTMENT
1.
Tune the receiver to the monochrome circular pattern.
2. Press PRESET switch (SW713 of the Main unit), and the
tuning bar is displayed on the screen,
3. Adjust the tuning bar center by using VR 791 on the control
unit.
4. Press PRESET switch.
GREY SCALE AND TRACKING ADJUSTMENT
1.
Tune the receiver to the monochrome circular pattern.
2. Set the brightness and the colour to normal , the contrast
to maximum.
3. Set the service switch (SW241 on the Main unit )and SW13B
on the AJV unit) at the service side.
4. Set the drive volume (VR681 and VR661 ) at their
mechanical center.
5. Set the bias volume (VR662, VR672 and VR682) to
minimum (fully counter clockwise).
6. Turn the screen volume to obtain just visible one coloured
line.
7. Adjust each bias volume (VR682- blue, VR672- green and
VR662- red) alternately until a dim white line produced,
8. Set the service switch (SW241 and SW13B) at the normal
side.
9, Adjust the drive volume (VR681 - blue and VR661 - red)
alternately to produce normal black and white picture.
10. Check for proper grey scale tracking at all brightness
levels.
NOTE: If grey scale adjustment is made after picture tube
replacement, check high voltage and sub- brightness
adjustment.
VERTICAL LINEALITY ADJUSTMENT
1.
Tune the receiver to the monochrome circular ~attern
2. Set the brightness and contrast to maximum. “
3. Adjust VR 461 to be A=B * 3mm.
COLOUR ADJUSTMENT (PAL~
~eceive
the PAL colour bar pattern(see Fig.1 )
Set controls: brightness and colour :maximum,
ADJUST
REMARKS
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1
—
2
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Connect tl
‘R251 ,T28
T211
oscilloscope to TP13B of the A/V unit.
Adjust VR251 ,T281 to obtain each 1 H
waveform(amplitude) for same as shown
below.
~lHi
$
...
Adjust T211 to obtain proper waveform as
shown above.
FOCUS ADJUSTMENT
Adjust focus control on the left side of the chassis for well
scaning lines.
VERTICAL SIZE ADJUSTMENT
1.
Tune the receiver to the monochrome circular pattern.
2. Adjust vertical size (VR451 ) control for full scan.
HORIZONTAL WIDTH ADJUSTMENT
1.
Tune the receiver to the monochrome circure pattern.
2. Set the brightness and the contrast to maximum.
3. If the picture is too wide or narrow, adjust the horizontal
width by using VR 481,
Note : Horiz. width adjustment effects the high voltage and
the sub- brightness. Therefore, recheck the sub-
brightness and the high voltage.
HIGH VOLTAGE CHECK
1.
Tune the receiver to the monochrom circular pattern.
2, Set the brightness and the contrast to minimum..
3, Connect the high voltage probe (+) to the anode lead of the
picture tube and the ground(-).
4, The high voltage must be less than 35.OKV.
Note: If the picture tube is replaced, check the high voltage.
SUB CONTRAST ADJUSTMENT
1,
Connect the oscillosco~e to TP - 6C(+),and TP - 6E(- ) of the
.,.
CRT unit.
.,
2. Receive the PAL Colour bar pattern,(see Fig 1,)
3. Set the colour to minimum.
Set the contrast to center (on screen
bar:1 6 pos.)
4. Adjust the brightness or sub-
=
brightness voiume (VR211 ) to be
“b=30 * 5V.”
5. AdjustVR1202(sub contrast volume)
on the video unit to be “a=60 t 2V.”
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