Service manual

Wells-Garnder Color Vector Monitor Guide
Page 37 of 73
COLOR PURITY
(Figure 6; from sections of the Wells-Gardner Service Manual)
As far as adjusting purity (red gun hits red phosphors only, green gun hits green, etc.) and
convergence (red, green, and blue guns hit adjacent dots to make white instead of separate
colors), the manual does a decent job of walking you through the procedure.
For best results, it is recommended that a purity adjustment be made with the monitor facing
west or east. The monitor must have been operating 15 minutes or more prior to this procedure.
1. With the yoke on the CRT neck, place the convergence assembly on CRT neck with the
center line (of Purity Adjustment Magnet) over gap between grids No. 3 and No. 4. The
convergence assembly consists of three sets of ring magnets with tabs (Figure 6).
FIGURE 6:
2. Tabs of the three magnetic ring-pairs are to be in a vertical position, which will produce a
zero-correction state and facilitate adjustments. (see Figure 6 above).
3. Connect a pattern generator or game board (in self-test mode), which can generate a
crosshatch pattern of red, green and blue independently and in combination of colors.
4. While displaying only a green crosshatch pattern, pull the deflection yoke backward as
far as it will go. Remove any glue that may be holding the purity ring magnets in place
and rotate one or both purity rings in a line so that they face opposite directions from