Sanyo CP21KS2K Service Manual Download Page 18

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Purity and Convergence Adjustment

RED

BLUE

Adjust tabs together to
superimpose red and
blue horizontal line.

Figure- 2 BLUE AND RED LINE MOVEMENT

Figure- 3 BLUE/RED AND GREEN MOVEMENT

Adjust tabs together to
superimpose red/blue
and green horizontal
line.

Adjust tabs angle to superimpose
blue and red vertical line.

Adjust tabs angle to superimpose
red/blue and green vertical line.

GREEN

BLUE / RED

CAUTION: The Convergence and Purity adjustments have been made at the factory. Readjustment
should be made only after picture tube or deflection yoke replacement, following the steps below:

PURITY ADJUSTMENT
1. Demagnetize the picture tube and receiver using an external

degaussing coil. When replacing picture tube or deflection
yoke, mount deflection yoke and purity-convergence magnets
assembly properly, see figures 1 and 4.

2. Turn Red and Blue guns off and provide only Green raster.

Rotate Screen control to fully counterclockwise. Rotate Red
and Blue Bias controls fully counterclockwise. Slowly rotate
Green Bias control clockwise to produce Green raster.

3. Loosen the screw holding the Deflection Yoke and remove the

3 Rubber Wedges, and slide the Deflection Yoke fully forward.

4. Rotate and spread the Tabs of the two Purity Magnets to cen-

tre the vertical green belt in the picture screen. The Purity
Magnets are also adjusted to obtain vertical centring of the
raster.

5. Slowly slide the Deflection Yoke backward until a uniform

green screen is obtained.

6. Check the purity of the red and blue screens for uniformity,

turn off other colours to check this (use bias controls).
Readjust the yoke position if necessary until all screens are
pure.

7. Adjust each Bias control and screen control to obtain white

raster. Refer to Gray Scale Adjustment. If part of the picture
screen is coloured, adjust the Deflection Yoke position forward
or backward slightly.

8. Tighten the mounting screw of the Deflection Yoke. Adjust

Convergence next.

CENTRE CONVERGENCE ADJUSTMENT
1. Use a dot crosshatch pattern signal.
2. Turn Red and Blue guns on and turn off Green gun. Adjust the

angle between the Tabs of the Four Pole Magnet 1 and 2, and
superimpose the Red and Blue vertical lines in the centre area
of the picture screen. Refer to figure 2.

3. Keeping the mutual angle of the Tabs of the Four Pole Magnet

turn them together to superimpose the Blue and Red horizon-
tal lines in the centre area of the picture screen. Refer to fig-
ure 2.

4. Turn Green gun on and adjust Six Pole Magnet 3 and 4 that

the Green line superimposed on the Red/Blue lines.
This is the same procedure used in steps 2 and 3.
Refer to figure 3.

OUTER AREA CONVERGENCE ADJUSTMENT

Slightly loosen the screw holding the Deflection Yoke. Adjust the
Deflection Yoke to converge the detail in the outer area (left side
and right side) of the picture screen by orbital movement of the
front of the Yoke, then secure the Deflection Yoke in appropriate
position by putting the wedges as illustrated. Tighten screw hold-
ing the Deflection Yoke.

RUBBER
WEDGE

DEFLECTION YOKE

DEFLECTION YOKE
MOUNTING SCREW

Figure 4. Deflection Yoke Movement

SIX-POLE
MAGNET TABS

FOUR-POLE
MAGNET TABS

ANGLE
OF TABS

PURITY
MAGNET
TABS

FOCUS GAP
(G3-G4)

Figure 1. Purity and Convergence Magnets

MAGNET TABS

ANGLE OF MAGNET TABS