Wells-Gardner D9100 service manual

7-3.8 Purity and Convergence Adjustment (continued)

⑧Check the purity of the red and blue raster by adjusting the bias controls.

⑨Obtain a white raster, referring to “CRT GRAY SCALE ADJUSTMENT”

⑩ Proceed with convergence adjustment.

2.Convergence adjustment:

① Change to a crosshatch pattern with a color signal generator.

② Adjust the BRIGHTNESS and CONTRAST controls for well defined pattern.

③ Adjust two tabs of the 4-pole magnets to change the angle between them and superimpose red and blue vertical

lines in the center of the picture screen.

④ Turn both tabs at the same time keeping their angles constant to superimpose red and blue horizontal lines at the center

of the screen.

⑤ Adjust two tabs of 6-pole magnets to superimpose red/blue line with green one. Adjusting the angle affects the vertical

lines and rotating both magnets affects the horizontal line.

⑥ Repeat adjustments 3,4 and 5, keeping in mind red, green

and blue movement, because 4-pole magnets and 6-pole magnets interact and make dot movement complex.

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