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TC-14A12P / TC-20B12
Service Adjustments and Calibrations
COLOR PURITY ADJUSTMENT
1. Position the CRT face turned to east or west.
2. Set Bright and Contrast controls to their maximum positions.
3. Leave the set heating up for 60 minutes at white screen.
4. Fully degauss the picture tube by using an external degauss coil.
5. Apply a red pattern.
6. Loose a clamp screw for the deflection yoke and move it forward
or backward until a uniform red screen is obtained.
7. Adjust rougly the Low Light controls and make sure that a uniform
white field is obtained.
8. Tighten the clamp screw.
Uniform red screen
CONVERGENCE CALIBRATION
1. Receive a crosshatch pattern and set Contrast control to the
maximum position.
2. Adjust Bright control to obtain a clear pattern.
3. Remove the DY wedges and slightly tilt the deflection yoke to
the vertically and horizontally to obtain the good overall
convergence.
4. Fix the deflection yoke by reinserting the DY wedges as showed
below.
5. If purity error is found, repeat “Color Purity” adjustment
Notes:
• Wedge A showed above should be fixed within a range of 45° to
the left of the vertical line shown.
• After inserting wedge A, insert wedges B, C and D. The wedges
should be set 90° apart from each other.
• Be certain that the four wedges are firmly fixed and the Deflection
Yoke is tightly clamped in place.
Otherwise the Deflection Yoke may shift its position and cause a
loss of convercence and purity.
Vertical
Horizontal
BGR
RGB
B
G
R
R
G
B
CRT
Screw for deflection yoke
Deflection yoke
BACKWAD FORWARD
à
à