4.7.8 PURITY AND CONVERGENCE PURITY ADJUSTMENT (1) Demagnetize CRT with the demagnetizer. (2) Loosen the retainer screw of the deflection yoke. (3) Remove the wedges. (4) Input a green raster signal from the signal generator, and turn the screen to green raster. (5) Move the deflection yoke backward. (6) Bring the long lug of the purity magnets on the short lug and position them horizontally. (Fig.2) (7) Adjust the gap between two lugs so that the GREEN RASTER will come into the center of the screen. (Fig.3) (8) Move the deflection yoke forward, and fix the position of the deflection yoke so that the whole screen will become green. (9) Insert the wedge to the top side of the deflection yoke so that it will not move. (10) Input a crosshatch signal. (11) Verify that the screen is horizontal. (12) Input red and blue raster signals, and make sure that purity is properly adjusted.
CRT
46
WEDGE DEFLECTION YOKE
P
P/C MAGNETS
P/C MAGNETS P : PURITY MAGNET 4 : 4 POLES (convergence magnets) 6 : 6 POLES (convergence magnets)
Fig.1
PURITY MAGNETS Long lug
Short lug Bring the long lug over the short lug and position them horizontally.
