Sony KV-28CS70B Service Manual ▷ View online
- 17 -
GREEN
BLUE
RED
a
b
c
d
Purity control corrects
this area
this area
Deflection yoke positioning
corrects these areas
corrects these areas
Disk magnets or
rotatable disk
magnets correct
these areas (a-d)
rotatable disk
magnets correct
these areas (a-d)
Disk Magnets
Preparation:
1.
In order to reduce the influence of geomagnetism on the
set’s picture tube, face it in an easterly or westerly direction.
set’s picture tube, face it in an easterly or westerly direction.
2.
Switch on the set’s power and degauss with the degausser.
1.
Input an all white signal from the pattern generator. Set the
Contrast and Brightness to normal.
Contrast and Brightness to normal.
2.
Set the pattern generator raster signal to Red.
3.
Move the deflection yoke forward and adjust with the
purity control so that the Red is at the centre and the Blue
and Green take up equally sized areas on each side of the
screen. [See Fig.3-1 - 3-3].
purity control so that the Red is at the centre and the Blue
and Green take up equally sized areas on each side of the
screen. [See Fig.3-1 - 3-3].
4.
Move the deflection yoke backwards and adjust so that the
entire screen becomes Red. [See Fig.3-1]
entire screen becomes Red. [See Fig.3-1]
5.
Switch the raster signal to Blue, then to Green and verify
the condition.
the condition.
6.
When the position of the deflection yoke has been
determined, fasten the deflection yoke with the screws.
determined, fasten the deflection yoke with the screws.
7.
If the beam does not land correctly in all the corners, use a
magnet to correct it. [See Fig.3-4]
magnet to correct it. [See Fig.3-4]
•
When complete readjustment is necessary or a new picture
tube is installed, carry out the following adjustments.
tube is installed, carry out the following adjustments.
•
Unless there are specific instructions to the contrary, carry
out these adjustments with the rated power supply.
out these adjustments with the rated power supply.
•
Unless there are specific instructions to the contrary, set the
controls and switches to the following settings :
controls and switches to the following settings :
Contrast
....................
80% [or remote control normal]
Brightness ...................
50%
Carry out the adjustments in the following order :
3-1.
3-1.
Beam Landing.
3-2.
Convergence.
3-3.
Focus.
3-4.
White Balance.
Note :
Test equipment required.
1.
1.
Color bar/pattern generator.
2.
Degausser.
3.
Oscilloscope.
4.
Digital multimeter.
Caution :
High voltages are present on the Deflection yoke terminals
- take care when handling the Deflection yoke whilst carrying
out adjustments.
- take care when handling the Deflection yoke whilst carrying
out adjustments.
Fig.3-4
Fig. 3-1.
Fig. 3-3.
Fig. 3-2.
Purity
SECTION 3
SET-UP ADJUSTMENTS
3-1. Beam Landing
- 18 -
4.
If the V.STAT magnet is moved in the direction of the (a)
and (b) arrows, the Red, Green and Blue points move as
and (b) arrows, the Red, Green and Blue points move as
indicated below.
1.
[Moving horizontally], adjust the H.STAT control so that
the Red, Green and Blue points are on top of each other at
the centre of the screen.
the Red, Green and Blue points are on top of each other at
the centre of the screen.
2.
[Moving vertically], adjust the V.STAT magnet so that the
Red, Green and Blue points are on top of each other at the
centre of the screen.
Red, Green and Blue points are on top of each other at the
centre of the screen.
3.
If the H.STAT variable resistor is unable to bring the Red,
Green and Blue points together at the centre of the screen,
adjust the horizontal convergence with the H.STAT variable
resistor and the V.STAT magnet in the manner indicated
below.
[In this case, the H.STAT variable resistor and the V.STAT
magnet influence each other].
Green and Blue points together at the centre of the screen,
adjust the horizontal convergence with the H.STAT variable
resistor and the V.STAT magnet in the manner indicated
below.
[In this case, the H.STAT variable resistor and the V.STAT
magnet influence each other].
The movement of the magnets interact with each other and so
the respective dot position should be monitored while carrying
out this adjustment.
Use the H.STAT VR to adjust the Red, Green and Blue dots so
that they coincide at the centre of the screen
(by moving the dots in the horizontal direction).
the respective dot position should be monitored while carrying
out this adjustment.
Use the H.STAT VR to adjust the Red, Green and Blue dots so
that they coincide at the centre of the screen
(by moving the dots in the horizontal direction).
G
B
R
G
B
R
G
B
R
G
B
R
G
B
R
G
B
R
3-2. Convergence
Preparation:
•
Before starting this adjustment, adjust the focus, horizontal
size and vertical size.
size and vertical size.
•
Minimize the Brightness setting.
•
Input a dot pattern from the pattern generator.
Horizontal and Vertical Static Convergence
Operation of the BMC (Hexapole) magnet.
Fig.3-5
•
Tilt the V.STAT magnet and adjust the static convergence by
opening or closing the V.STAT magnet.
opening or closing the V.STAT magnet.
B
G
R
B
G
R
a
a
b
b
a
b
B
G
R
a
a
B
G
R
b
b
B
G
R
a
b
R
G
B
b
a
Center dot
R
G
B
R
G
B
C Board
RV702 (H STAT)
H STAT Convergence
(on mount side)
H STAT Convergence
(on mount side)
H STAT
convergence
control
V.STAT Vertical Static Magnet
- 19 -
+
+
+
TLV VR 28"
Deflection Yoke
+
+
+
+
TLV VR 32"
Deflection Yoke
+
+
+
YCH VR 28"
Deflection Yoke
+
+
+
+
YCH VR 32"
Deflection Yoke
Tilt Direction
If you are unable to adjust the corner convergence properly,
this can be corrected with the use of permalloy magnets.
this can be corrected with the use of permalloy magnets.
HTIL correction can be performed by adding one TLH
correction assembly to the Deflection yoke.
correction assembly to the Deflection yoke.
HTIL Adjustment
YCH Adjustment
TLV Adjustment
Geometry Adjustment.
Preparation:
Before starting this adjustment, adjust the horizontal and
vertical static convergence.
vertical static convergence.
1.
Remove the deflection yoke spacer.
2.
Tilt the deflection yoke as indicated in the figure below and
optimise the geometry.
Tilting the DY Up and Down a small amount will balance
the upper and lower pin adjustment.
optimise the geometry.
Tilting the DY Up and Down a small amount will balance
the upper and lower pin adjustment.
3.
Re-install the deflection yoke spacers. Ensure 4 DY spacers are
reinserted
reinserted
Screen Corner Convergence
a
b
d
Permalloy Assy
c
Install the permalloy assembly
for the area that needs correcting.
for the area that needs correcting.
X-4387-214-1
Convergence adjustment with permalloy
APH circuit
harness
harness
Deflection Yoke
TLH Piece
H-Trap
YCH
TLV
Deflection Yoke
TLH Piece
H-Trap
YCH
TLV
4.
The H-Trap and T-B Pin may not achieve a good level due
to a small tilt allowance on the square DY. Keep the DY in
a straight position and adjust H-Trap pot (See diagram for
HTIL Adjustment) and Y-Mg for T-B Pin, as below.
to a small tilt allowance on the square DY. Keep the DY in
a straight position and adjust H-Trap pot (See diagram for
HTIL Adjustment) and Y-Mg for T-B Pin, as below.
28”
32”
• APH Convergence parameter is electrically controlled. For this
reason a TLH piece may not be required.
(APH = Red vertical lines on the edge of the screen).
reason a TLH piece may not be required.
(APH = Red vertical lines on the edge of the screen).
a-d: screen-corner
convergence defect
convergence defect
a
b
c
d
- 20 -
1.
Receive a television broadcast signal.
2.
Normalize the picture setting.
3.
Adjust the focus control located on the flyback transformer
to obtain the best focus at the centre of the screen.
Bring only the centre area of the screen into focus, the
magenta-ring appears on the screen. In this case, adjust the
focus to optimize the screen uniformly.
to obtain the best focus at the centre of the screen.
Bring only the centre area of the screen into focus, the
magenta-ring appears on the screen. In this case, adjust the
focus to optimize the screen uniformly.
3-4. Screen (G2), White Balance
[Adjustment in the service mode using the remote
commander]
commander]
G2 adjustment
Layout of each control
White balance adjustment for TV mode
V.STAT
BMC (Hexapole)
Purity
3-3. Focus Adjustment
Screen
Focus
1.
Input a dot signal from the pattern generator.
2.
Set the Picture, Brightness and Colour to minimum.
3.
Apply 165V DC from an external power supply to the R, G
and B cathodes of the CRT.
and B cathodes of the CRT.
4.
Whilst watching the picture, adjust the G2 control [SCREEN]
located on the flyback transformer to the point just before the
flyback return lines disappear.
located on the flyback transformer to the point just before the
flyback return lines disappear.
1.
Input an all-white signal from the pattern generator.
2.
Set the TV set or operation in Service Mode.
[ See Page 21 ].
[ See Page 21 ].
3.
Select ‘Service’ from the on screen menu display and press
‘Right Arrow’.
‘Right Arrow’.
4.
The ‘Service’ menu will appear on the screen.[See Page 21]
5.
Set the ‘Subcont’ to MAX.
6.
Set the ‘R-Drive’ to 50.
7.
Adjust the ‘G-Drive’ and the ‘B-Drive’ so that the white
balance becomes optimum.
balance becomes optimum.
8.
Press the ‘OK’ button to write the data for each item.
9.
Set the ‘Subcont’ to MIN.
10. Adjust the ‘Cutoff Br.’ with the left and right buttons on the
remote commander so that the white balance becomes optimum.
11. Press the ‘OK’ button to write the data.
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